Commit Graph

90 Commits

Author SHA1 Message Date
Daniel Bristot de Oliveira ba6c89ab3b watchdog: Improve watchdog_dev function documentation
Adjust function comments to the kernel doc format. It
also adjusts some variable names and adds return values.

No functional change.

Changes from V1:
  Change "Returns" to "Return:" (Randy Dunlap)

Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/30378a03e9cd9b5f6e92ec9bf512edc38bad8627.1644589712.git.bristot@kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2022-03-27 17:04:08 +02:00
Jan Kiszka dbe80cf471 watchdog: Start watchdog in watchdog_set_last_hw_keepalive only if appropriate
We must not pet a running watchdog when handle_boot_enabled is off
because this will kick off automatic triggering before userland is
running, defeating the purpose of the handle_boot_enabled control.
Furthermore, don't ping in case watchdog_set_last_hw_keepalive was
called incorrectly when the hardware watchdog is actually not running.

Fixed: cef9572e9a ("watchdog: add support for adjusting last known HW keepalive time")
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/93d56386-6e37-060b-55ce-84de8cde535f@web.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2021-08-22 10:28:12 +02:00
Grzegorz Jaszczyk 60bcd91aaf watchdog: introduce watchdog_dev_suspend/resume
The watchdog drivers often disable wdog clock during suspend and then
enable it again during resume. Nevertheless the ping worker is still
running and can issue low-level ping while the wdog clock is disabled
causing the system hang. To prevent such condition register pm notifier
in the watchdog core which will call watchdog_dev_suspend/resume and
actually cancel ping worker during suspend and restore it back, if
needed, during resume.

Signed-off-by: Grzegorz Jaszczyk <grzegorz.jaszczyk@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210618195033.3209598-2-grzegorz.jaszczyk@linaro.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2021-08-22 10:28:08 +02:00
Curtis Klein c7b178dae1 watchdog: Fix NULL pointer dereference when releasing cdev
watchdog_hrtimer_pretimeout_stop needs the watchdog device to have a
valid pointer to the watchdog core data to stop the pretimeout hrtimer.
Therefore it needs to be called before the pointers are cleared in
watchdog_cdev_unregister.

Fixes: 7b7d2fdc8c ("watchdog: Add hrtimer-based pretimeout feature")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Curtis Klein <curtis.klein@hpe.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1624429583-5720-1-git-send-email-curtis.klein@hpe.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2021-08-22 10:28:07 +02:00
Curtis Klein cf6ea95423 watchdog: only run driver set_pretimeout op if device supports it
Some watchdog devices might conditionally support pretimeouts (e.g. if
an interrupt is exposed for the device) but some watchdog drivers might
still define the set_pretimeout operation (e.g. the mtk_wdt driver) and
indicate support at runtime through the WDIOF_PRETIMEOUT flag. If the
kernel is compiled with CONFIG_WATCHDOG_HRTIMER_PRETIMEOUT enabled,
watchdog_set_pretimeout would run the driver specific set_pretimeout
even if WDIOF_PRETIMEOUT is not set which might have unintended
consequences.

So this change checks that the device flags and only runs the driver
operation if pretimeouts are supported.

Signed-off-by: Curtis Klein <curtis.klein@hpe.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1624751265-24785-1-git-send-email-curtis.klein@hpe.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2021-08-22 10:28:07 +02:00
Curtis Klein 7b7d2fdc8c watchdog: Add hrtimer-based pretimeout feature
This adds the option to use a hrtimer to generate a watchdog pretimeout
event for hardware watchdogs that do not natively support watchdog
pretimeouts.

With this enabled, all watchdogs will appear to have pretimeout support
in userspace. If no pretimeout value is set, there will be no change in
the watchdog's behavior. If a pretimeout value is set for a specific
watchdog that does not have built-in pretimeout support, a timer will be
started that should fire at the specified time before the watchdog
timeout would occur. When the watchdog is successfully pinged, the timer
will be restarted. If the timer is allowed to fire it will generate a
pretimeout event. However because a software timer is used, it may not
be able to fire in every circumstance.

If the watchdog does support a pretimeout natively, that functionality
will be used instead of the hrtimer.

The general design of this feaure was inspired by the software watchdog,
specifically its own pretimeout implementation. However the software
watchdog and this feature are completely independent. They can be used
together; with or without CONFIG_SOFT_WATCHDOG_PRETIMEOUT enabled.

The main advantage of using the hrtimer pretimeout with a hardware
watchdog, compared to running the software watchdog with a hardware
watchdog, is that if the hardware watchdog driver is unable to ping the
watchdog (e.g. due to a bus or communication error), then the hrtimer
pretimeout would still fire whereas the software watchdog would not.

Signed-off-by: Curtis Klein <curtis.klein@hpe.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1612383090-27110-1-git-send-email-curtis.klein@hpe.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2021-06-21 08:49:13 +02:00
Juerg Haefliger 3bb21781d1 watchdog: Use sysfs_emit() and sysfs_emit_at() in "show" functions
Convert sprintf() in sysfs "show" functions to sysfs_emit() and
sysfs_emit_at() in order to check for buffer overruns in sysfs outputs.

Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210511061812.480172-1-juergh@canonical.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2021-06-21 08:49:03 +02:00
Juerg Haefliger 6ddf5087f8 watchdog: Add {min,max}_timeout sysfs nodes
The valid range for the 'timeout' value is useful information so expose
the min and max timeout values via sysfs.

Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210511062953.485252-1-juergh@canonical.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2021-06-21 08:49:02 +02:00
Zhen Lei 2c904630e9 watchdog: remove unneeded inclusion of <uapi/linux/sched/types.h>
There has been no reference to "struct sched_param" since
commit 94beddacb5 ("sched,watchdog: Convert to sched_set_fifo()"), so
there's no need to include <uapi/linux/sched/types.h> any more, delete
it.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200827062154.1847-1-thunder.leizhen@huawei.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-10-14 15:02:24 +02:00
Dinghao Liu 937425d4cd watchdog: Use put_device on error
We should use put_device() instead of freeing device
directly after device_initialize().

Fixes: cb36e29bb0 ("watchdog: initialize device before misc_register")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200824031230.31050-1-dinghao.liu@zju.edu.cn
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-10-14 15:02:24 +02:00
Dinghao Liu 5afb6d203d watchdog: Fix memleak in watchdog_cdev_register
When watchdog_kworker is NULL, we should free wd_data
before the function returns to prevent memleak.

Fixes: 664a39236e ("watchdog: Introduce hardware maximum heartbeat in watchdog core")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200824024001.25474-1-dinghao.liu@zju.edu.cn
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-10-14 15:02:23 +02:00
Linus Torvalds 4586039427 linux-watchdog 5.9-rc1 tag
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Merge tag 'linux-watchdog-5.9-rc1' of git://www.linux-watchdog.org/linux-watchdog

Pull watchdog updates from Wim Van Sebroeck:

 - f71808e_wdt imporvements

 - dw_wdt improvements

 - mlx-wdt: support new watchdog type with longer timeout period

 - fallthrough pseudo-keyword replacements

 - overall small fixes and improvements

* tag 'linux-watchdog-5.9-rc1' of git://www.linux-watchdog.org/linux-watchdog: (35 commits)
  watchdog: rti-wdt: balance pm runtime enable calls
  watchdog: rti-wdt: attach to running watchdog during probe
  watchdog: add support for adjusting last known HW keepalive time
  watchdog: use __watchdog_ping in startup
  watchdog: softdog: Add options 'soft_reboot_cmd' and 'soft_active_on_boot'
  watchdog: pcwd_usb: remove needless check before usb_free_coherent()
  watchdog: Replace HTTP links with HTTPS ones
  dt-bindings: watchdog: renesas,wdt: Document r8a774e1 support
  watchdog: initialize device before misc_register
  watchdog: booke_wdt: Add common nowayout parameter driver
  watchdog: scx200_wdt: Use fallthrough pseudo-keyword
  watchdog: Use fallthrough pseudo-keyword
  watchdog: f71808e_wdt: do stricter parameter validation
  watchdog: f71808e_wdt: clear watchdog timeout occurred flag
  watchdog: f71808e_wdt: remove use of wrong watchdog_info option
  watchdog: f71808e_wdt: indicate WDIOF_CARDRESET support in watchdog_info.options
  docs: watchdog: codify ident.options as superset of possible status flags
  dt-bindings: watchdog: Add compatible for QCS404, SC7180, SDM845, SM8150
  dt-bindings: watchdog: Convert QCOM watchdog timer bindings to YAML
  watchdog: dw_wdt: Add DebugFS files
  ...
2020-08-12 12:13:44 -07:00
Tero Kristo cef9572e9a watchdog: add support for adjusting last known HW keepalive time
Certain watchdogs require the watchdog only to be pinged within a
specific time window, pinging too early or too late cause the watchdog
to fire. In cases where this sort of watchdog has been started before
kernel comes up, we must adjust the watchdog keepalive window to match
the actually running timer, so add a new driver API for this purpose.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200717132958.14304-3-t-kristo@ti.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-08-05 18:43:02 +02:00
Tero Kristo fbbe35dfcf watchdog: use __watchdog_ping in startup
Current watchdog startup functionality does not respect the minimum hw
heartbeat setup and the last watchdog ping timeframe when watchdog is
already running and userspace process attaches to it. Fix this by using
the __watchdog_ping from the startup also. For this code path, we can
also let the __watchdog_ping handle the bookkeeping for the worker and
last keepalive times.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200717132958.14304-2-t-kristo@ti.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-08-05 18:43:02 +02:00
Krzysztof Sobota cb36e29bb0 watchdog: initialize device before misc_register
When watchdog device is being registered, it calls misc_register that
makes watchdog available for systemd to open. This is a data race
scenario, because when device is open it may still have device struct
not initialized - this in turn causes a crash. This patch moves
device initialization before misc_register call and it solves the
problem printed below.

------------[ cut here ]------------
WARNING: CPU: 3 PID: 1 at lib/kobject.c:612 kobject_get+0x50/0x54
kobject: '(null)' ((ptrval)): is not initialized, yet kobject_get() is being called.
Modules linked in: k2_reset_status(O) davinci_wdt(+) sfn_platform_hwbcn(O) fsmddg_sfn(O) clk_misc_mmap(O) clk_sw_bcn(O) fsp_reset(O) cma_mod(O) slave_sup_notif(O) fpga_master(O) latency(O+) evnotify(O) enable_arm_pmu(O) xge(O) rio_mport_cdev br_netfilter bridge stp llc nvrd_checksum(O) ipv6
CPU: 3 PID: 1 Comm: systemd Tainted: G           O      4.19.113-g2579778-fsm4_k2 #1
Hardware name: Keystone
[<c02126c4>] (unwind_backtrace) from [<c020da94>] (show_stack+0x18/0x1c)
[<c020da94>] (show_stack) from [<c07f87d8>] (dump_stack+0xb4/0xe8)
[<c07f87d8>] (dump_stack) from [<c0221f70>] (__warn+0xfc/0x114)
[<c0221f70>] (__warn) from [<c0221fd8>] (warn_slowpath_fmt+0x50/0x74)
[<c0221fd8>] (warn_slowpath_fmt) from [<c07fd394>] (kobject_get+0x50/0x54)
[<c07fd394>] (kobject_get) from [<c0602ce8>] (get_device+0x1c/0x24)
[<c0602ce8>] (get_device) from [<c06961e0>] (watchdog_open+0x90/0xf0)
[<c06961e0>] (watchdog_open) from [<c06001dc>] (misc_open+0x130/0x17c)
[<c06001dc>] (misc_open) from [<c0388228>] (chrdev_open+0xec/0x1a8)
[<c0388228>] (chrdev_open) from [<c037fa98>] (do_dentry_open+0x204/0x3cc)
[<c037fa98>] (do_dentry_open) from [<c0391e2c>] (path_openat+0x330/0x1148)
[<c0391e2c>] (path_openat) from [<c0394518>] (do_filp_open+0x78/0xec)
[<c0394518>] (do_filp_open) from [<c0381100>] (do_sys_open+0x130/0x1f4)
[<c0381100>] (do_sys_open) from [<c0201000>] (ret_fast_syscall+0x0/0x28)
Exception stack(0xd2ceffa8 to 0xd2cefff0)
ffa0:                   b6f69968 00000000 ffffff9c b6ebd210 000a0001 00000000
ffc0: b6f69968 00000000 00000000 00000142 fffffffd ffffffff 00b65530 bed7bb78
ffe0: 00000142 bed7ba70 b6cc2503 b6cc41d6
---[ end trace 7b16eb105513974f ]---

------------[ cut here ]------------
WARNING: CPU: 3 PID: 1 at lib/refcount.c:153 kobject_get+0x24/0x54
refcount_t: increment on 0; use-after-free.
Modules linked in: k2_reset_status(O) davinci_wdt(+) sfn_platform_hwbcn(O) fsmddg_sfn(O) clk_misc_mmap(O) clk_sw_bcn(O) fsp_reset(O) cma_mod(O) slave_sup_notif(O) fpga_master(O) latency(O+) evnotify(O) enable_arm_pmu(O) xge(O) rio_mport_cdev br_netfilter bridge stp llc nvrd_checksum(O) ipv6
CPU: 3 PID: 1 Comm: systemd Tainted: G        W  O      4.19.113-g2579778-fsm4_k2 #1
Hardware name: Keystone
[<c02126c4>] (unwind_backtrace) from [<c020da94>] (show_stack+0x18/0x1c)
[<c020da94>] (show_stack) from [<c07f87d8>] (dump_stack+0xb4/0xe8)
[<c07f87d8>] (dump_stack) from [<c0221f70>] (__warn+0xfc/0x114)
[<c0221f70>] (__warn) from [<c0221fd8>] (warn_slowpath_fmt+0x50/0x74)
[<c0221fd8>] (warn_slowpath_fmt) from [<c07fd368>] (kobject_get+0x24/0x54)
[<c07fd368>] (kobject_get) from [<c0602ce8>] (get_device+0x1c/0x24)
[<c0602ce8>] (get_device) from [<c06961e0>] (watchdog_open+0x90/0xf0)
[<c06961e0>] (watchdog_open) from [<c06001dc>] (misc_open+0x130/0x17c)
[<c06001dc>] (misc_open) from [<c0388228>] (chrdev_open+0xec/0x1a8)
[<c0388228>] (chrdev_open) from [<c037fa98>] (do_dentry_open+0x204/0x3cc)
[<c037fa98>] (do_dentry_open) from [<c0391e2c>] (path_openat+0x330/0x1148)
[<c0391e2c>] (path_openat) from [<c0394518>] (do_filp_open+0x78/0xec)
[<c0394518>] (do_filp_open) from [<c0381100>] (do_sys_open+0x130/0x1f4)
[<c0381100>] (do_sys_open) from [<c0201000>] (ret_fast_syscall+0x0/0x28)
Exception stack(0xd2ceffa8 to 0xd2cefff0)
ffa0:                   b6f69968 00000000 ffffff9c b6ebd210 000a0001 00000000
ffc0: b6f69968 00000000 00000000 00000142 fffffffd ffffffff 00b65530 bed7bb78
ffe0: 00000142 bed7ba70 b6cc2503 b6cc41d6
---[ end trace 7b16eb1055139750 ]---

Fixes: 72139dfa24 ("watchdog: Fix the race between the release of watchdog_core_data and cdev")
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Krzysztof Sobota <krzysztof.sobota@nokia.com>
Link: https://lore.kernel.org/r/20200717103109.14660-1-krzysztof.sobota@nokia.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-08-05 18:43:00 +02:00
Gustavo A. R. Silva bd490f8222 watchdog: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200707171121.GA13472@embeddedor
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-08-05 18:42:53 +02:00
Wang Qing 893c3d82b4 watchdog: Use kobj_to_dev() API
Use kobj_to_dev() API instead of container_of().

Signed-off-by: Wang Qing <wangqing@vivo.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1591945384-14587-1-git-send-email-wangqing@vivo.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-08-05 18:42:46 +02:00
Bumsik Kim 0be01476dd watchdog: test_bit() => watchdog_active()
Use the dedicated function watchdog_active()
instead of the generic test_bit() function.

It is done using the following Coccinelle script:

@@
identifier wdd;
@@
- test_bit(WDOG_ACTIVE, &wdd->status)
+ watchdog_active(wdd)

Signed-off-by: Bumsik Kim <k.bumsik@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200529012428.84684-1-k.bumsik@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-08-05 18:42:46 +02:00
Peter Zijlstra 94beddacb5 sched,watchdog: Convert to sched_set_fifo()
Because SCHED_FIFO is a broken scheduler model (see previous patches)
take away the priority field, the kernel can't possibly make an
informed decision.

Effectively changes prio from 99 to 50.

Cc: wim@linux-watchdog.org
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
2020-06-15 14:10:24 +02:00
Tero Kristo 982bb70517 watchdog: reset last_hw_keepalive time at start
Currently the watchdog core does not initialize the last_hw_keepalive
time during watchdog startup. This will cause the watchdog to be pinged
immediately if enough time has passed from the system boot-up time, and
some types of watchdogs like K3 RTI does not like this.

To avoid the issue, setup the last_hw_keepalive time during watchdog
startup.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200302200426.6492-3-t-kristo@ti.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-03-18 11:15:25 +01:00
Vladis Dronov 69503e5851 watchdog: fix UAF in reboot notifier handling in watchdog core code
After the commit 44ea39420f ("drivers/watchdog: make use of
devm_register_reboot_notifier()") the struct notifier_block reboot_nb in
the struct watchdog_device is removed from the reboot notifiers chain at
the time watchdog's chardev is closed. But at least in i6300esb.c case
reboot_nb is embedded in the struct esb_dev which can be freed on its
device removal and before the chardev is closed, thus UAF at reboot:

[    7.728581] esb_probe: esb_dev.watchdog_device ffff91316f91ab28
ts# uname -r                            note the address ^^^
5.5.0-rc5-ae6088-wdog
ts# ./openwdog0 &
[1] 696
ts# opened /dev/watchdog0, sleeping 10s...
ts# echo 1 > /sys/devices/pci0000\:00/0000\:00\:09.0/remove
[  178.086079] devres:rel_nodes: dev ffff91317668a0b0 data ffff91316f91ab28
           esb_dev.watchdog_device.reboot_nb memory is freed here ^^^
ts# ...woken up
[  181.459010] devres:rel_nodes: dev ffff913171781000 data ffff913174a1dae8
[  181.460195] devm_unreg_reboot_notifier: res ffff913174a1dae8 nb ffff91316f91ab78
                                     attempt to use memory already freed ^^^
[  181.461063] devm_unreg_reboot_notifier: nb->call 6b6b6b6b6b6b6b6b
[  181.461243] devm_unreg_reboot_notifier: nb->next 6b6b6b6b6b6b6b6b
                freed memory is filled with a slub poison ^^^
[1]+  Done                    ./openwdog0
ts# reboot
[  229.921862] systemd-shutdown[1]: Rebooting.
[  229.939265] notifier_call_chain: nb ffffffff9c6c2f20 nb->next ffffffff9c6d50c0
[  229.943080] notifier_call_chain: nb ffffffff9c6d50c0 nb->next 6b6b6b6b6b6b6b6b
[  229.946054] notifier_call_chain: nb 6b6b6b6b6b6b6b6b INVAL
[  229.957584] general protection fault: 0000 [#1] SMP
[  229.958770] CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 5.5.0-rc5-ae6088-wdog
[  229.960224] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ...
[  229.963288] RIP: 0010:notifier_call_chain+0x66/0xd0
[  229.969082] RSP: 0018:ffffb20dc0013d88 EFLAGS: 00010246
[  229.970812] RAX: 000000000000002e RBX: 6b6b6b6b6b6b6b6b RCX: 00000000000008b3
[  229.972929] RDX: 0000000000000000 RSI: 0000000000000096 RDI: ffffffff9ccc46ac
[  229.975028] RBP: 0000000000000001 R08: 0000000000000000 R09: 00000000000008b3
[  229.977039] R10: 0000000000000001 R11: ffffffff9c26c740 R12: 0000000000000000
[  229.979155] R13: 6b6b6b6b6b6b6b6b R14: 0000000000000000 R15: 00000000fffffffa
...   slub_debug=FZP poison ^^^
[  229.989089] Call Trace:
[  229.990157]  blocking_notifier_call_chain+0x43/0x59
[  229.991401]  kernel_restart_prepare+0x14/0x30
[  229.992607]  kernel_restart+0x9/0x30
[  229.993800]  __do_sys_reboot+0x1d2/0x210
[  230.000149]  do_syscall_64+0x3d/0x130
[  230.001277]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  230.002639] RIP: 0033:0x7f5461bdd177
[  230.016402] Modules linked in: i6300esb
[  230.050261] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Fix the crash by reverting 44ea39420f so unregister_reboot_notifier()
is called when watchdog device is removed. This also makes handling of
the reboot notifier unified with the handling of the restart handler,
which is freed with unregister_restart_handler() in the same place.

Fixes: 44ea39420f ("drivers/watchdog: make use of devm_register_reboot_notifier()")
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: Vladis Dronov <vdronov@redhat.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200108125347.6067-1-vdronov@redhat.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-01-27 15:55:46 +01:00
Linus Torvalds 4a08fe5792 linux-watchdog 5.5-rc1 tag
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Merge tag 'linux-watchdog-5.5-rc1' of git://www.linux-watchdog.org/linux-watchdog

Pull watchdog updates from Wim Van Sebroeck:

 - support for NCT6116D

 - several small fixes and improvements

* tag 'linux-watchdog-5.5-rc1' of git://www.linux-watchdog.org/linux-watchdog: (24 commits)
  watchdog: jz4740: Drop dependency on MACH_JZ47xx
  watchdog: jz4740: Use regmap provided by TCU driver
  watchdog: jz4740: Use WDT clock provided by TCU driver
  dt-bindings: watchdog: sama5d4_wdt: add microchip,sam9x60-wdt compatible
  watchdog: sama5d4_wdt: cleanup the bit definitions
  watchdog: sprd: Fix the incorrect pointer getting from driver data
  watchdog: aspeed: Fix clock behaviour for ast2600
  watchdog: imx7ulp: Fix reboot hang
  watchdog: make nowayout sysfs file writable
  watchdog: prevent deferral of watchdogd wakeup on RT
  watchdog: imx7ulp: Use definitions instead of magic values
  watchdog: imx7ulp: Remove inline annotations
  watchdog: imx7ulp: Remove unused structure member
  watchdog: imx7ulp: Pass the wdog instance inimx7ulp_wdt_enable()
  watchdog: wdat_wdt: Spelling s/configrable/configurable/
  watchdog: bd70528: Trivial function documentation fix
  watchdog: cadence: Do not show error in case of deferred probe
  watchdog: Fix the race between the release of watchdog_core_data and cdev
  watchdog: sbc7240_wdt: Fix yet another -Wimplicit-fallthrough warning
  watchdog: intel-mid_wdt: Add WATCHDOG_NOWAYOUT support
  ...
2019-12-01 18:01:03 -08:00
Rasmus Villemoes bc44fa734c watchdog: make nowayout sysfs file writable
It can be useful to delay setting the nowayout feature for a watchdog
device. Moreover, not every driver (notably gpio_wdt) implements a
nowayout module parameter/otherwise respects CONFIG_WATCHDOG_NOWAYOUT,
and modifying those drivers carries a risk of causing a regression for
someone who has two watchdog devices, sets CONFIG_WATCHDOG_NOWAYOUT
and somehow relies on the gpio_wdt driver being ignorant of
that (i.e., allowing one to gracefully close a gpio_wdt but not the
other watchdog in the system).

So instead, simply make the nowayout sysfs file writable. Obviously,
setting nowayout is a one-way street.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191105205118.11359-1-linux@rasmusvillemoes.dk
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-11-18 19:53:43 +01:00
Julia Cartwright a19f89335f watchdog: prevent deferral of watchdogd wakeup on RT
When PREEMPT_RT is enabled, all hrtimer expiry functions are
deferred for execution into the context of ksoftirqd unless otherwise
annotated.

Deferring the expiry of the hrtimer used by the watchdog core, however,
is a waste, as the callback does nothing but queue a kthread work item
and wakeup watchdogd.

It's worst then that, too: the deferral through ksoftirqd also means
that for correct behavior a user must adjust the scheduling parameters
of both watchdogd _and_ ksoftirqd, which is unnecessary and has other
side effects (like causing unrelated expiry functions to execute at
potentially elevated priority).

Instead, mark the hrtimer used by the watchdog core as being _HARD to
allow it's execution directly from hardirq context.  The work done in
this expiry function is well-bounded and minimal.

A user still must adjust the scheduling parameters of the watchdogd
to be correct w.r.t. their application needs.

Link: https://lkml.kernel.org/r/0e02d8327aeca344096c246713033887bc490dd7.1538089180.git.julia@ni.com
Cc: Guenter Roeck <linux@roeck-us.net>
Reported-and-tested-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Reported-by: Tim Sander <tim@krieglstein.org>
Signed-off-by: Julia Cartwright <julia@ni.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
[bigeasy: use only HRTIMER_MODE_REL_HARD]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191105144506.clyadjbvnn7b7b2m@linutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-11-18 19:53:43 +01:00
Kevin Hao 72139dfa24 watchdog: Fix the race between the release of watchdog_core_data and cdev
The struct cdev is embedded in the struct watchdog_core_data. In the
current code, we manage the watchdog_core_data with a kref, but the
cdev is manged by a kobject. There is no any relationship between
this kref and kobject. So it is possible that the watchdog_core_data is
freed before the cdev is entirely released. We can easily get the
following call trace with CONFIG_DEBUG_KOBJECT_RELEASE and
CONFIG_DEBUG_OBJECTS_TIMERS enabled.
  ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x38
  WARNING: CPU: 23 PID: 1028 at lib/debugobjects.c:481 debug_print_object+0xb0/0xf0
  Modules linked in: softdog(-) deflate ctr twofish_generic twofish_common camellia_generic serpent_generic blowfish_generic blowfish_common cast5_generic cast_common cmac xcbc af_key sch_fq_codel openvswitch nsh nf_conncount nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4
  CPU: 23 PID: 1028 Comm: modprobe Not tainted 5.3.0-next-20190924-yoctodev-standard+ #180
  Hardware name: Marvell OcteonTX CN96XX board (DT)
  pstate: 00400009 (nzcv daif +PAN -UAO)
  pc : debug_print_object+0xb0/0xf0
  lr : debug_print_object+0xb0/0xf0
  sp : ffff80001cbcfc70
  x29: ffff80001cbcfc70 x28: ffff800010ea2128
  x27: ffff800010bad000 x26: 0000000000000000
  x25: ffff80001103c640 x24: ffff80001107b268
  x23: ffff800010bad9e8 x22: ffff800010ea2128
  x21: ffff000bc2c62af8 x20: ffff80001103c600
  x19: ffff800010e867d8 x18: 0000000000000060
  x17: 0000000000000000 x16: 0000000000000000
  x15: ffff000bd7240470 x14: 6e6968207473696c
  x13: 5f72656d6974203a x12: 6570797420746365
  x11: 6a626f2029302065 x10: 7461747320657669
  x9 : 7463612820657669 x8 : 3378302f3078302b
  x7 : 0000000000001d7a x6 : ffff800010fd5889
  x5 : 0000000000000000 x4 : 0000000000000000
  x3 : 0000000000000000 x2 : ffff000bff948548
  x1 : 276a1c9e1edc2300 x0 : 0000000000000000
  Call trace:
   debug_print_object+0xb0/0xf0
   debug_check_no_obj_freed+0x1e8/0x210
   kfree+0x1b8/0x368
   watchdog_cdev_unregister+0x88/0xc8
   watchdog_dev_unregister+0x38/0x48
   watchdog_unregister_device+0xa8/0x100
   softdog_exit+0x18/0xfec4 [softdog]
   __arm64_sys_delete_module+0x174/0x200
   el0_svc_handler+0xd0/0x1c8
   el0_svc+0x8/0xc

This is a common issue when using cdev embedded in a struct.
Fortunately, we already have a mechanism to solve this kind of issue.
Please see commit 233ed09d7f ("chardev: add helper function to
register char devs with a struct device") for more detail.

In this patch, we choose to embed the struct device into the
watchdog_core_data, and use the API provided by the commit 233ed09d7f
to make sure that the release of watchdog_core_data and cdev are
in sequence.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191008112934.29669-1-haokexin@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-11-18 19:53:40 +01:00
Arnd Bergmann b6dfb2477f compat_ioctl: move WDIOC handling into wdt drivers
All watchdog drivers implement the same set of ioctl commands, and
fortunately all of them are compatible between 32-bit and 64-bit
architectures.

Modern drivers always go through drivers/watchdog/wdt.c as an abstraction
layer, but older ones implement their own file_operations on a character
device for this.

Move the handling from fs/compat_ioctl.c into the individual drivers.

Note that most of the legacy drivers will never be used on 64-bit
hardware, because they are for an old 32-bit SoC implementation, but
doing them all at once is safer than trying to guess which ones do
or do not need the compat_ioctl handling.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-10-23 17:23:46 +02:00
Guenter Roeck d017327893 watchdog: convert remaining drivers to use SPDX license identifier
This gets rid of the unnecessary license boilerplate, and avoids
having to deal with individual patches one by one.

No functional changes.

Reviewed-by: Jerry Hoemann <jerry.hoemann@hpe.com>
Acked-by: Sylvain Lemieux <slemieux.tyco@gmail.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-07-08 20:35:11 +02:00
Rasmus Villemoes c2eac35bc2 watchdog: make the device time out at open_deadline when open_timeout is used
When the watchdog device is not open by userspace, the kernel takes
care of pinging it. When the open_timeout feature is in use, we should
ensure that the hardware fires close to open_timeout seconds after the
kernel has assumed responsibility for the device.

To do this, simply reuse the logic that is already in place for
ensuring the same thing when userspace is responsible for regularly
pinging the device:

- When watchdog_active(wdd), this patch doesn't change anything.

- When !watchdog_active(wdd), the "virtual timeout" should be taken to
be ->open_deadline". When the open_timeout feature is not used or the
device has been opened at least once, ->open_deadline is KTIME_MAX,
and the arithmetic ends up returning keepalive_interval as we used to.

This has been tested on a Wandboard with various combinations of
open_timeout and timeout-sec properties for the on-board watchdog by
booting with 'init=/bin/sh', timestamping the lines on the serial
console, and comparing the timestamp of the 'imx2-wdt 20bc000.wdog:
timeout nnn sec' line with the timestamp of the 'U-Boot SPL ...'
line (which appears just after reset).

Suggested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-07-08 20:04:13 +02:00
Rasmus Villemoes 487e4e0822 watchdog: introduce CONFIG_WATCHDOG_OPEN_TIMEOUT
This allows setting a default value for the watchdog.open_timeout
commandline parameter via Kconfig.

Some BSPs allow remote updating of the kernel image and root file
system, but updating the bootloader requires physical access. Hence, if
one has a firmware update that requires relaxing the
watchdog.open_timeout a little, the value used must be baked into the
kernel image itself and cannot come from the u-boot environment via the
kernel command line.

Being able to set the initial value in .config doesn't change the fact
that the value on the command line, if present, takes precedence, and is
of course immensely useful for development purposes while one has
console acccess, as well as usable in the cases where one can make a
permanent update of the kernel command line.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-07-08 20:04:13 +02:00
Rasmus Villemoes 4d1c6a0ec2 watchdog: introduce watchdog.open_timeout commandline parameter
The watchdog framework takes care of feeding a hardware watchdog until
userspace opens /dev/watchdogN. If that never happens for some reason
(buggy init script, corrupt root filesystem or whatnot) but the kernel
itself is fine, the machine stays up indefinitely. This patch allows
setting an upper limit for how long the kernel will take care of the
watchdog, thus ensuring that the watchdog will eventually reset the
machine.

A value of 0 (the default) means infinite timeout, preserving the
current behaviour.

This is particularly useful for embedded devices where some fallback
logic is implemented in the bootloader (e.g., use a different root
partition, boot from network, ...).

There is already handle_boot_enabled serving a similar purpose. However,
such a binary choice is unsuitable if the hardware watchdog cannot be
programmed by the bootloader to provide a timeout long enough for
userspace to get up and running. Many of the embedded devices we see use
external (gpio-triggered) watchdogs with a fixed timeout of the order of
1-2 seconds.

The open timeout only applies for the first open from
userspace. Should userspace need to close the watchdog device, with
the intention of re-opening it shortly, the application can emulate
the open timeout feature by combining the nowayout feature with an
appropriate WDIOC_SETTIMEOUT immediately prior to closing the device.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-07-08 20:04:13 +02:00
Kirill Smelkov c5bf68fe0c *: convert stream-like files from nonseekable_open -> stream_open
Using scripts/coccinelle/api/stream_open.cocci added in 10dce8af34
("fs: stream_open - opener for stream-like files so that read and write
can run simultaneously without deadlock"), search and convert to
stream_open all in-kernel nonseekable_open users for which read and
write actually do not depend on ppos and where there is no other methods
in file_operations which assume @offset access.

I've verified each generated change manually - that it is correct to convert -
and each other nonseekable_open instance left - that it is either not correct
to convert there, or that it is not converted due to current stream_open.cocci
limitations. The script also does not convert files that should be valid to
convert, but that currently have .llseek = noop_llseek or generic_file_llseek
for unknown reason despite file being opened with nonseekable_open (e.g.
drivers/input/mousedev.c)

Among cases converted 14 were potentially vulnerable to read vs write deadlock
(see details in 10dce8af34):

	drivers/char/pcmcia/cm4000_cs.c:1685:7-23: ERROR: cm4000_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	drivers/gnss/core.c:45:1-17: ERROR: gnss_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	drivers/hid/uhid.c:635:1-17: ERROR: uhid_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	drivers/infiniband/core/user_mad.c:988:1-17: ERROR: umad_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	drivers/input/evdev.c:527:1-17: ERROR: evdev_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	drivers/input/misc/uinput.c:401:1-17: ERROR: uinput_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	drivers/isdn/capi/capi.c:963:8-24: ERROR: capi_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	drivers/leds/uleds.c:77:1-17: ERROR: uleds_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	drivers/media/rc/lirc_dev.c:198:1-17: ERROR: lirc_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	drivers/s390/char/fs3270.c:488:1-17: ERROR: fs3270_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	drivers/usb/misc/ldusb.c:310:1-17: ERROR: ld_usb_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	drivers/xen/evtchn.c:667:8-24: ERROR: evtchn_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	net/batman-adv/icmp_socket.c:80:1-17: ERROR: batadv_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.
	net/rfkill/core.c:1146:8-24: ERROR: rfkill_fops: .read() can deadlock .write(); change nonseekable_open -> stream_open to fix.

and the rest were just safe to convert to stream_open because their read and
write do not use ppos at all and corresponding file_operations do not
have methods that assume @offset file access(*):

	arch/powerpc/platforms/52xx/mpc52xx_gpt.c:631:8-24: WARNING: mpc52xx_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	arch/powerpc/platforms/cell/spufs/file.c:591:8-24: WARNING: spufs_ibox_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	arch/powerpc/platforms/cell/spufs/file.c:591:8-24: WARNING: spufs_ibox_stat_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	arch/powerpc/platforms/cell/spufs/file.c:591:8-24: WARNING: spufs_mbox_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	arch/powerpc/platforms/cell/spufs/file.c:591:8-24: WARNING: spufs_mbox_stat_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	arch/powerpc/platforms/cell/spufs/file.c:591:8-24: WARNING: spufs_wbox_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	arch/powerpc/platforms/cell/spufs/file.c:591:8-24: WARNING: spufs_wbox_stat_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	arch/um/drivers/harddog_kern.c:88:8-24: WARNING: harddog_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	arch/x86/kernel/cpu/microcode/core.c:430:33-49: WARNING: microcode_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/char/ds1620.c:215:8-24: WARNING: ds1620_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/char/dtlk.c:301:1-17: WARNING: dtlk_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/char/ipmi/ipmi_watchdog.c:840:9-25: WARNING: ipmi_wdog_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/char/pcmcia/scr24x_cs.c:95:8-24: WARNING: scr24x_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/char/tb0219.c:246:9-25: WARNING: tb0219_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/firewire/nosy.c:306:8-24: WARNING: nosy_ops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/hwmon/fschmd.c:840:8-24: WARNING: watchdog_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/hwmon/w83793.c:1344:8-24: WARNING: watchdog_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/infiniband/core/ucma.c:1747:8-24: WARNING: ucma_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/infiniband/core/ucm.c:1178:8-24: WARNING: ucm_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/infiniband/core/uverbs_main.c:1086:8-24: WARNING: uverbs_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/input/joydev.c:282:1-17: WARNING: joydev_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/pci/switch/switchtec.c:393:1-17: WARNING: switchtec_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/platform/chrome/cros_ec_debugfs.c:135:8-24: WARNING: cros_ec_console_log_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/rtc/rtc-ds1374.c:470:9-25: WARNING: ds1374_wdt_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/rtc/rtc-m41t80.c:805:9-25: WARNING: wdt_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/s390/char/tape_char.c:293:2-18: WARNING: tape_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/s390/char/zcore.c:194:8-24: WARNING: zcore_reipl_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/s390/crypto/zcrypt_api.c:528:8-24: WARNING: zcrypt_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/spi/spidev.c:594:1-17: WARNING: spidev_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/staging/pi433/pi433_if.c:974:1-17: WARNING: pi433_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/acquirewdt.c:203:8-24: WARNING: acq_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/advantechwdt.c:202:8-24: WARNING: advwdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/alim1535_wdt.c:252:8-24: WARNING: ali_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/alim7101_wdt.c:217:8-24: WARNING: wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/ar7_wdt.c:166:8-24: WARNING: ar7_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/at91rm9200_wdt.c:113:8-24: WARNING: at91wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/ath79_wdt.c:135:8-24: WARNING: ath79_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/bcm63xx_wdt.c:119:8-24: WARNING: bcm63xx_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/cpu5wdt.c:143:8-24: WARNING: cpu5wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/cpwd.c:397:8-24: WARNING: cpwd_fops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/eurotechwdt.c:319:8-24: WARNING: eurwdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/f71808e_wdt.c:528:8-24: WARNING: watchdog_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/gef_wdt.c:232:8-24: WARNING: gef_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/geodewdt.c:95:8-24: WARNING: geodewdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/ib700wdt.c:241:8-24: WARNING: ibwdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/ibmasr.c:326:8-24: WARNING: asr_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/indydog.c:80:8-24: WARNING: indydog_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/intel_scu_watchdog.c:307:8-24: WARNING: intel_scu_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/iop_wdt.c:104:8-24: WARNING: iop_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/it8712f_wdt.c:330:8-24: WARNING: it8712f_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/ixp4xx_wdt.c:68:8-24: WARNING: ixp4xx_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/ks8695_wdt.c:145:8-24: WARNING: ks8695wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/m54xx_wdt.c:88:8-24: WARNING: m54xx_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/machzwd.c:336:8-24: WARNING: zf_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/mixcomwd.c:153:8-24: WARNING: mixcomwd_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/mtx-1_wdt.c:121:8-24: WARNING: mtx1_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/mv64x60_wdt.c:136:8-24: WARNING: mv64x60_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/nuc900_wdt.c:134:8-24: WARNING: nuc900wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/nv_tco.c:164:8-24: WARNING: nv_tco_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/pc87413_wdt.c:289:8-24: WARNING: pc87413_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/pcwd.c:698:8-24: WARNING: pcwd_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/pcwd.c:737:8-24: WARNING: pcwd_temp_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/pcwd_pci.c:581:8-24: WARNING: pcipcwd_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/pcwd_pci.c:623:8-24: WARNING: pcipcwd_temp_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/pcwd_usb.c:488:8-24: WARNING: usb_pcwd_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/pcwd_usb.c:527:8-24: WARNING: usb_pcwd_temperature_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/pika_wdt.c:121:8-24: WARNING: pikawdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/pnx833x_wdt.c:119:8-24: WARNING: pnx833x_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/rc32434_wdt.c:153:8-24: WARNING: rc32434_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/rdc321x_wdt.c:145:8-24: WARNING: rdc321x_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/riowd.c:79:1-17: WARNING: riowd_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/sa1100_wdt.c:62:8-24: WARNING: sa1100dog_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/sbc60xxwdt.c:211:8-24: WARNING: wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/sbc7240_wdt.c:139:8-24: WARNING: wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/sbc8360.c:274:8-24: WARNING: sbc8360_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/sbc_epx_c3.c:81:8-24: WARNING: epx_c3_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/sbc_fitpc2_wdt.c:78:8-24: WARNING: fitpc2_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/sb_wdog.c:108:1-17: WARNING: sbwdog_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/sc1200wdt.c:181:8-24: WARNING: sc1200wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/sc520_wdt.c:261:8-24: WARNING: wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/sch311x_wdt.c:319:8-24: WARNING: sch311x_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/scx200_wdt.c:105:8-24: WARNING: scx200_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/smsc37b787_wdt.c:369:8-24: WARNING: wb_smsc_wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/w83877f_wdt.c:227:8-24: WARNING: wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/w83977f_wdt.c:301:8-24: WARNING: wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/wafer5823wdt.c:200:8-24: WARNING: wafwdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/watchdog_dev.c:828:8-24: WARNING: watchdog_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/wdrtas.c:379:8-24: WARNING: wdrtas_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/wdrtas.c:445:8-24: WARNING: wdrtas_temp_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/wdt285.c:104:1-17: WARNING: watchdog_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/wdt977.c:276:8-24: WARNING: wdt977_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/wdt.c:424:8-24: WARNING: wdt_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/wdt.c:484:8-24: WARNING: wdt_temp_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/wdt_pci.c:464:8-24: WARNING: wdtpci_fops: .write() has stream semantic; safe to change nonseekable_open -> stream_open.
	drivers/watchdog/wdt_pci.c:527:8-24: WARNING: wdtpci_temp_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	net/batman-adv/log.c:105:1-17: WARNING: batadv_log_fops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	sound/core/control.c:57:7-23: WARNING: snd_ctl_f_ops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.
	sound/core/rawmidi.c:385:7-23: WARNING: snd_rawmidi_f_ops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	sound/core/seq/seq_clientmgr.c:310:7-23: WARNING: snd_seq_f_ops: .read() and .write() have stream semantic; safe to change nonseekable_open -> stream_open.
	sound/core/timer.c:1428:7-23: WARNING: snd_timer_f_ops: .read() has stream semantic; safe to change nonseekable_open -> stream_open.

One can also recheck/review the patch via generating it with explanation comments included via

	$ make coccicheck MODE=patch COCCI=scripts/coccinelle/api/stream_open.cocci SPFLAGS="-D explain"

(*) This second group also contains cases with read/write deadlocks that
stream_open.cocci don't yet detect, but which are still valid to convert to
stream_open since ppos is not used. For example drivers/pci/switch/switchtec.c
calls wait_for_completion_interruptible() in its .read, but stream_open.cocci
currently detects only "wait_event*" as blocking.

Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yongzhi Pan <panyongzhi@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Nikolaus Rath <Nikolaus@rath.org>
Cc: Han-Wen Nienhuys <hanwen@google.com>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James R. Van Zandt" <jrv@vanzandt.mv.com>
Cc: Corey Minyard <minyard@acm.org>
Cc: Harald Welte <laforge@gnumonks.org>
Acked-by: Lubomir Rintel <lkundrak@v3.sk> [scr24x_cs]
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Johan Hovold <johan@kernel.org>
Cc: David Herrmann <dh.herrmann@googlemail.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: Jean Delvare <jdelvare@suse.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>	[watchdog/* hwmon/*]
Cc: Rudolf Marek <r.marek@assembler.cz>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Kurt Schwemmer <kurt.schwemmer@microsemi.com>
Acked-by: Logan Gunthorpe <logang@deltatee.com> [drivers/pci/switch/switchtec]
Acked-by: Bjorn Helgaas <bhelgaas@google.com> [drivers/pci/switch/switchtec]
Cc: Benson Leung <bleung@chromium.org>
Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> [platform/chrome]
Cc: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> [rtc/*]
Cc: Mark Brown <broonie@kernel.org>
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Zwane Mwaikambo <zwanem@gmail.com>
Cc: Marek Lindner <mareklindner@neomailbox.ch>
Cc: Simon Wunderlich <sw@simonwunderlich.de>
Cc: Antonio Quartulli <a@unstable.cc>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
2019-05-06 17:46:41 +03:00
Wolfram Sang 953b9dd772 watchdog: core: fix null pointer dereference when releasing cdev
watchdog_stop() calls watchdog_update_worker() which needs a valid
wdd->wd_data pointer. So, when unregistering the cdev, clear the
pointers after we call watchdog_stop(), not before.

Fixes: bb292ac1c6 ("watchdog: Introduce watchdog_stop_on_unregister helper")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2018-10-02 13:32:24 +02:00
Christophe Leroy 1ff688209e watchdog: core: make sure the watchdog_worker is not deferred
commit 4cd13c21b2 ("softirq: Let ksoftirqd do its job") has the
effect of deferring timer handling in case of high CPU load, hence
delaying the delayed work allthought the worker is running which
high realtime priority.

As hrtimers are not managed by softirqs, this patch replaces the
delayed work by a plain work and uses an hrtimer to schedule that work.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Guenter Roeck <Linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2018-01-21 12:44:59 +01:00
Christophe Leroy 38a1222ae4 watchdog: core: make sure the watchdog worker always works
When running a command like 'chrt -f 50 dd if=/dev/zero of=/dev/null',
the watchdog_worker fails to service the HW watchdog and the
HW watchdog fires long before the watchdog soft timeout.

At the moment, the watchdog_worker is invoked as a delayed work.
Delayed works are handled by non realtime kernel threads. The
WQ_HIGHPRI flag only increases the niceness of that threads.

This patch replaces the delayed work logic by kthread delayed work,
and sets the associated kernel task to SCHED_FIFO with the highest
priority, in order to ensure that the watchdog worker will run as
soon as possible.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2017-12-28 20:45:57 +01:00
Gustavo A. R. Silva e2af3092d0 watchdog: watchdog_dev: mark expected switch fall-through
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that in this particular case I replaced "Fall" with a proper
"fall through" comment, which is what GCC is expecting to find.

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2017-12-28 20:45:30 +01:00
Guenter Roeck 914d65f3f0 watchdog: Fix kref imbalance seen if handle_boot_enabled=0
If handle_boot_enabled is set to 0, the watchdog driver module use
counter will not be increased and kref_get() will not be called when
registering the watchdog. Subsequently, on open, this does not happen
either because the code believes that it was already done because the
hardware watchdog is marked as running.

We could introduce a state variable to indicate this state, but let's
just increase the module use counter and call kref_get() unconditionally
if the hardware watchdog is running when a driver is registering itself
to keep the code simple.

Fixes: 2501b01531 ("watchdog: core: add option to avoid early ...")
Cc: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2017-12-17 11:01:48 +01:00
Guenter Roeck 4bcd615fad watchdog: Fix potential kref imbalance when opening watchdog
If a watchdog driver's open function sets WDOG_HW_RUNNING with the
expectation that the watchdog can not be stopped, but then stops the
watchdog anyway in its stop function, kref_get() wil not be called in
watchdog_open(). If the watchdog then stops on close, WDOG_HW_RUNNING
will be cleared and kref_put() will be called, causing a kref imbalance.
As result the character device data structure will be released, which in
turn will cause the system to crash on the next call to watchdog_open().

Fixes: ee142889e3 ("watchdog: Introduce WDOG_HW_RUNNING flag")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2017-12-17 11:01:47 +01:00
Andrey Smirnov 44ea39420f drivers/watchdog: make use of devm_register_reboot_notifier()
Save a bit of cleanup code by leveraging newly added
devm_register_reboot_notifier().

[akpm@linux-foundation.org: small cleanup: avoid 80-col tricks]
Link: http://lkml.kernel.org/r/20170411160615.9784-1-andrew.smirnov@gmail.com
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-17 16:10:04 -08:00
Rasmus Villemoes c013b65ad8 watchdog: introduce watchdog_worker_should_ping helper
This will be useful when the condition becomes slightly more
complicated in the next patch.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Esben Haabendal <esben@haabendal.dk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2017-07-03 13:59:05 +02:00
Sebastian Reichel 2501b01531 watchdog: core: add option to avoid early handling of watchdog
On some systems its desirable to have watchdog reboot the system
when it does not come up fast enough. This adds a kernel parameter
to disable the auto-update of watchdog before userspace takes over
and a kernel option to set the default. The info messages were
added to shorten error searching on misconfigured systems.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2017-06-05 20:55:17 +02:00
Guenter Roeck bb292ac1c6 watchdog: Introduce watchdog_stop_on_unregister helper
Many watchdog drivers explicitly stop the watchdog when unregistering it.
While it is unclear if this is actually needed (the whatdog should not be
running at that time if it can be stopped), introduce a helper to
explicitly stop the watchdog in the watchdog core when unregistering it.
This helps reducing driver code size while retaining functionality.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-02-24 14:00:23 -08:00
Vladimir Zapolskiy 89873a711d watchdog: pretimeout: add pretimeout_available_governors attribute
The change adds an option to a user with CONFIG_WATCHDOG_SYSFS and
CONFIG_WATCHDOG_PRETIMEOUT_GOV enabled to get information about all
registered watchdog pretimeout governors by reading watchdog device
attribute named "pretimeout_available_governors".

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2016-10-08 10:27:24 +02:00
Vladimir Zapolskiy 53f96cee1a watchdog: pretimeout: add option to select a pretimeout governor in runtime
The change converts watchdog device attribute "pretimeout_governor" from
read-only to read-write type to allow users to select a desirable
watchdog pretimeout governor in runtime, e.g.

  % echo -n panic > /sys/..../watchdog/watchdog0/pretimeout

To get this working a list of registered pretimeout governors is created
and a new helper function watchdog_pretimeout_governor_set() is exported
to watchdog_dev.c.

If a selected governor is gone, a watchdog device pretimeout notification
is delegated to a default built-in pretimeout governor.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2016-10-08 10:27:20 +02:00
Vladimir Zapolskiy ff84136cb6 watchdog: add watchdog pretimeout governor framework
The change adds a simple watchdog pretimeout framework infrastructure,
its purpose is to allow users to select a desired handling of watchdog
pretimeout events, which may be generated by some watchdog devices.

A user selects a default watchdog pretimeout governor during
compilation stage.

Watchdogs with WDIOF_PRETIMEOUT capability now have one more device
attribute in sysfs, pretimeout_governor attribute is intended to display
the selected watchdog pretimeout governor.

The framework has no impact at runtime on watchdog devices with no
WDIOF_PRETIMEOUT capability set.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2016-10-08 10:27:10 +02:00
Wolfram Sang df044e0220 watchdog: add pretimeout support to the core
Since the watchdog framework centrializes the IOCTL interfaces of device
drivers now, SETPRETIMEOUT and GETPRETIMEOUT need to be added in the
common code.

Signed-off-by: Robin Gong <b38343@freescale.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
[vzapolskiy: added conditional pretimeout sysfs attribute visibility]
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2016-09-24 09:27:15 +02:00
Guenter Roeck 3c10bbde10 watchdog: core: Clear WDOG_HW_RUNNING before calling the stop function
WDOG_HW_RUNNING indicates that the hardware watchdog is running while the
watchdog device is closed. The flag may be set by the driver when it is
instantiated to indicate that the watchdog is running, and that the
watchdog core needs to send heartbeat requests to the driver until the
watchdog device is opened.

When the watchdog device is closed, the flag can be used by the driver's
stop function to indicate to the watchdog core that it was unable to stop
the watchdog, and that the watchdog core needs to send heartbeat requests.
This only works if the flag is actually cleared when the watchdog is
stopped. To avoid having to clear the flag in each driver's stop function,
clear it in the watchdog core before calling the stop function.

Reported-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Fixes: ee142889e3 ("watchdog: Introduce WDOG_HW_RUNNING flag")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2016-07-25 12:03:04 +02:00
Wei Yongjun 138913cb63 watchdog: core: Fix error handling of watchdog_dev_init()
Fix the error handling paths of watchdog_dev_init().

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2016-07-25 12:02:55 +02:00
Guenter Roeck 90b826f17a watchdog: Implement status function in watchdog core
Up to now, the watchdog status function called a driver function,
which was supposed to return the watchdog status. All but one
driver using the watchdog core did not implement this function,
and the driver implementing it did not implement it correctly
(the function is supposed to return WDIOF_ flags). At the same time,
at least some of the status information can be provided by the watchdog
core.

Provide the available status bits directly from the watchdog driver core.
Call the driver status function if it exists to get the boot status, but
always provide WDIOF_MAGICCLOSE and WDIOF_KEEPALIVEPING internally.
This patch makes the 'status' sysfs attribute always available.
This attribute is now displayed as hex number with 0x prepended to be
easier to decode.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2016-07-19 10:09:07 +02:00
Rasmus Villemoes 3fbfe92647 watchdog: change watchdog_need_worker logic
If the driver indicates that the watchdog is running, the framework
should feed it until userspace opens the device, regardless of whether
the driver has set max_hw_heartbeat_ms.

This patch only affects the case where wdd->max_hw_heartbeat_ms is
zero, wdd->timeout is non-zero, the watchdog is not active and the
hardware device is running (*):

- If wdd->timeout is zero, watchdog_need_worker() returns false both
before and after this patch, and watchdog_next_keepalive() is not
called.

- If watchdog_active(wdd), the return value from watchdog_need_worker
is also the same as before (namely, hm && t > hm). Hence in that case,
watchdog_next_keepalive() is only called if hm == max_hw_heartbeat_ms
is non-zero, so the change to min_not_zero there is a no-op.

- If the watchdog is not active and the device is not running, we
return false from watchdog_need_worker just as before.

That leaves the watchdog_hw_running(wdd) && !watchdog_active(wdd) &&
wdd->timeout case. Again, it's easy to see that if
wdd->max_hw_heartbeat_ms is non-zero, we return true from
watchdog_need_worker with and without this patch, and the logic in
watchdog_next_keepalive is unchanged. Finally, if
wdd->max_hw_heartbeat_ms is 0, we used to end up in the
cancel_delayed_work branch, whereas with this patch we end up
scheduling a ping timeout_ms/2 from now.

(*) This should imply that no current kernel drivers are affected,
since the only drivers which explicitly set WDOG_HW_RUNNING are
imx2_wdt.c and dw_wdt.c, both of which also provide a non-zero value
for max_hw_heartbeat_ms. The watchdog core also sets WDOG_HW_RUNNING,
but only when the driver doesn't provide ->stop, in which case it
must, according to Documentation/watchdog/watchdog-kernel-api.txt, set
max_hw_heartbeat_ms.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2016-07-17 21:25:53 +02:00
Guenter Roeck e1f30282a1 watchdog: core: Fix circular locking dependency
lockdep reports the following circular locking dependency.

======================================================
INFO: possible circular locking dependency detected ]
4.6.0-rc3-00191-gfabf418 #162 Not tainted
-------------------------------------------------------
systemd/1 is trying to acquire lock:
((&(&wd_data->work)->work)){+.+...}, at: [<80141650>] flush_work+0x0/0x280

but task is already holding lock:

(&wd_data->lock){+.+...}, at: [<804acfa8>] watchdog_release+0x18/0x190

which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:

-> #1 (&wd_data->lock){+.+...}:
	[<80662310>] mutex_lock_nested+0x64/0x4a8
	[<804aca4c>] watchdog_ping_work+0x18/0x4c
	[<80143128>] process_one_work+0x1ac/0x500
	[<801434b4>] worker_thread+0x38/0x554
	[<80149510>] kthread+0xf4/0x108
	[<80107c10>] ret_from_fork+0x14/0x24

-> #0 ((&(&wd_data->work)->work)){+.+...}:
	[<8017c4e8>] lock_acquire+0x70/0x90
	[<8014169c>] flush_work+0x4c/0x280
	[<801440f8>] __cancel_work_timer+0x9c/0x1e0
	[<804acfcc>] watchdog_release+0x3c/0x190
	[<8022c5e8>] __fput+0x80/0x1c8
	[<80147b28>] task_work_run+0x94/0xc8
	[<8010b998>] do_work_pending+0x8c/0xb4
	[<80107ba8>] slow_work_pending+0xc/0x20

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0                    CPU1
----                    ----
lock(&wd_data->lock);
                        lock((&(&wd_data->work)->work));
                        lock(&wd_data->lock);
lock((&(&wd_data->work)->work));

*** DEADLOCK ***

1 lock held by systemd/1:

stack backtrace:
CPU: 2 PID: 1 Comm: systemd Not tainted 4.6.0-rc3-00191-gfabf418 #162
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[<8010f5e4>] (unwind_backtrace) from [<8010c038>] (show_stack+0x10/0x14)
[<8010c038>] (show_stack) from [<8039d7fc>] (dump_stack+0xa8/0xd4)
[<8039d7fc>] (dump_stack) from [<80177ee0>] (print_circular_bug+0x214/0x334)
[<80177ee0>] (print_circular_bug) from [<80179230>] (check_prevs_add+0x4dc/0x8e8)
[<80179230>] (check_prevs_add) from [<8017b3d8>] (__lock_acquire+0xc6c/0x14ec)
[<8017b3d8>] (__lock_acquire) from [<8017c4e8>] (lock_acquire+0x70/0x90)
[<8017c4e8>] (lock_acquire) from [<8014169c>] (flush_work+0x4c/0x280)
[<8014169c>] (flush_work) from [<801440f8>] (__cancel_work_timer+0x9c/0x1e0)
[<801440f8>] (__cancel_work_timer) from [<804acfcc>] (watchdog_release+0x3c/0x190)
[<804acfcc>] (watchdog_release) from [<8022c5e8>] (__fput+0x80/0x1c8)
[<8022c5e8>] (__fput) from [<80147b28>] (task_work_run+0x94/0xc8)
[<80147b28>] (task_work_run) from [<8010b998>] (do_work_pending+0x8c/0xb4)
[<8010b998>] (do_work_pending) from [<80107ba8>] (slow_work_pending+0xc/0x20)

Turns out the call to cancel_delayed_work_sync() in watchdog_release()
is not necessary and can be dropped. If the worker is no longer necessary,
the subsequent call to watchdog_update_worker() will cancel it. If it is
already running, it won't do anything, since the worker function checks
if it needs to ping the watchdog or not.

Reported-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Tested-by: Clemens Gruber <clemens.gruber@pqgruber.com>
Fixes: 11d7aba9ce ("watchdog: imx2: Convert to use infrastructure triggered keepalives")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: stable <stable@vger.kernel.org>
2016-05-14 16:10:33 +02:00