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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
...
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>
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>
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>
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>
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>
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>
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>
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>
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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
...
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Smatch rightfully complains that wdd is dereferenced in the watchdog
release function after being checked for NULL. Also make sure that it
is not accessed outside mutex protection to avoid use-after-free problems.
Fixes: e6c71e84e4c0 ("watchdog: Introduce WDOG_HW_RUNNING flag")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Some watchdogs require a minimum time between heartbeats.
Examples are the watchdogs in DA9062 and AT91SAM9x.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Not all hardware watchdogs can be stopped. The driver for
such watchdogs would typically only set the WATCHDOG_HW_RUNNING
flag in its stop function. Make the stop function optional and set
WATCHDOG_HW_RUNNING in the watchdog core if it is not provided.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The WDOG_HW_RUNNING flag is expected to be set by watchdog drivers if
the hardware watchdog is running. If the flag is set, the watchdog
subsystem will ping the watchdog even if the watchdog device is closed.
The watchdog driver stop function is now optional and may be omitted
if the watchdog can not be stopped. If stopping the watchdog is not
possible but the driver implements a stop function, it is responsible
to set the WDOG_HW_RUNNING flag in its stop function.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Introduce an optional hardware maximum heartbeat in the watchdog core.
The hardware maximum heartbeat can be lower than the maximum timeout.
Drivers can set the maximum hardware heartbeat value in the watchdog data
structure. If the configured timeout exceeds the maximum hardware heartbeat,
the watchdog core enables a timer function to assist sending keepalive
requests to the watchdog driver.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
For some watchdogs, the watchdog driver handles timeout changes without
explicitly setting any registers. In this situation, the watchdog driver
might only set the 'timeout' variable but do nothing else.
This can as well be handled by the infrastructure, so make the set_timeout
callback optional. If WDIOF_SETTIMEOUT is configured but the .set_timeout
callback is not available, update the timeout variable in the
infrastructure code.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The lifetime of the watchdog device pointer is different from the lifetime
of its character device. Remove it entirely to avoid race conditions.
Signed-off-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>
The Zodiac watchdog driver attaches additional sysfs attributes to the
watchdog device. This has a number of problems: The watchdog device
lifetime differs from the driver lifetime, and the device structure
should therefore not be accessed from drivers. Also, creating sysfs
attributes after driver registration results in a potential race condition
if user space expects the attributes to exist but they don't exist yet.
Add support for creating driver specific sysfs attributes to the watchdog
core to solve the problems.
Signed-off-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>
All variables required by the watchdog core to manage a watchdog are
currently stored in struct watchdog_device. The lifetime of those
variables is determined by the watchdog driver. However, the lifetime
of variables used by the watchdog core differs from the lifetime of
struct watchdog_device. To remedy this situation, watchdog drivers
can implement ref and unref callbacks, to be used by the watchdog
core to lock struct watchdog_device in memory.
While this solves the immediate problem, it depends on watchdog drivers
to actually implement the ref/unref callbacks. This is error prone,
often not implemented in the first place, or not implemented correctly.
To solve the problem without requiring driver support, split the variables
in struct watchdog_device into two data structures - one for variables
associated with the watchdog driver, one for variables associated with
the watchdog core. With this approach, the watchdog core can keep track
of its variable lifetime and no longer depends on ref/unref callbacks
in the driver. As a side effect, some of the variables originally in
struct watchdog_driver are now private to the watchdog core and no longer
visible in watchdog drivers.
As a side effect of the changes made, an ioctl will now always fail
with -ENODEV after a watchdog device was unregistered with the character
device still open. Previously, it would only fail with -ENODEV in some
situations. Also, ioctl operations are now atomic from driver perspective.
With this change, it is now guaranteed that the driver will not unregister
a watchdog between a timeout change and the subsequent ping.
The 'ref' and 'unref' callbacks in struct watchdog_driver are no longer
used and marked as deprecated.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The watchdog character device is currently created in watchdog_dev.c,
and the watchdog device in watchdog_core.c. This results in
cross-dependencies, since device creation needs to know the watchdog
character device number as well as the watchdog class, both of which
reside in watchdog_dev.c.
Create the watchdog device in watchdog_dev.c to simplify the code.
Inspired by earlier patch set from Damien Riegel.
Cc: Damien Riegel <damien.riegel@savoirfairelinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This patch adds following attributes to watchdog device's sysfs interface
to read its different status.
* state - reads whether device is active or not
* identity - reads Watchdog device's identity string.
* timeout - reads current timeout.
* timeleft - reads timeleft before watchdog generates a reset
* bootstatus - reads status of the watchdog device at boot
* status - reads watchdog device's internal status bits
* nowayout - reads whether nowayout feature was set or not
Testing with iTCO_wdt:
# cd /sys/class/watchdog/watchdog1/
# ls
bootstatus dev device identity nowayout power state
subsystem timeleft timeout uevent
# cat identity
iTCO_wdt
# cat timeout
30
# cat state
inactive
# echo > /dev/watchdog1
# cat timeleft
26
# cat state
active
# cat bootstatus
0
# cat nowayout
0
Signed-off-by: Pratyush Anand <panand@redhat.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>
Linus Torvalds