Drop monitor uses a work item that takes care of constructing and
sending netlink notifications to user space. In case drop monitor never
started to monitor, then the work item is uninitialized and not
associated with a function.
Therefore, a stop command from user space results in canceling an
uninitialized work item which leads to the following warning [1].
Fix this by not processing a stop command if drop monitor is not
currently monitoring.
[1]
[ 31.735402] ------------[ cut here ]------------
[ 31.736470] WARNING: CPU: 0 PID: 143 at kernel/workqueue.c:3032 __flush_work+0x89f/0x9f0
...
[ 31.738120] CPU: 0 PID: 143 Comm: dwdump Not tainted 5.5.0-custom-09491-g16d4077796b8 #727
[ 31.741968] RIP: 0010:__flush_work+0x89f/0x9f0
...
[ 31.760526] Call Trace:
[ 31.771689] __cancel_work_timer+0x2a6/0x3b0
[ 31.776809] net_dm_cmd_trace+0x300/0xef0
[ 31.777549] genl_rcv_msg+0x5c6/0xd50
[ 31.781005] netlink_rcv_skb+0x13b/0x3a0
[ 31.784114] genl_rcv+0x29/0x40
[ 31.784720] netlink_unicast+0x49f/0x6a0
[ 31.787148] netlink_sendmsg+0x7cf/0xc80
[ 31.790426] ____sys_sendmsg+0x620/0x770
[ 31.793458] ___sys_sendmsg+0xfd/0x170
[ 31.802216] __sys_sendmsg+0xdf/0x1a0
[ 31.806195] do_syscall_64+0xa0/0x540
[ 31.806885] entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fixes: 8e94c3bc92 ("drop_monitor: Allow user to start monitoring hardware drops")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Convert the equivalent but rather odd uses of kmemdup with
__GFP_ZERO to the more common kstrdup and avoid unnecessary
zeroing of copied over memory.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When working in 'packet' mode, drop monitor generates a notification
with a potentially truncated payload of the dropped packet. The payload
is copied from the MAC header, but I forgot to check that the MAC header
was set, so do it now.
Fixes: ca30707dee ("drop_monitor: Add packet alert mode")
Fixes: 5e58109b1e ("drop_monitor: Add support for packet alert mode for hardware drops")
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Timestamps are currently communicated to user space as 'struct
timespec', which is not considered y2038 safe since it uses a 32-bit
signed value for seconds.
Fix this while the API is still not part of any official kernel release
by using 64-bit nanoseconds timestamps instead.
Fixes: ca30707dee ("drop_monitor: Add packet alert mode")
Fixes: 5e58109b1e ("drop_monitor: Add support for packet alert mode for hardware drops")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Drop monitor has start and stop commands, but so far these were only
used to start and stop monitoring of software drops.
Now that drop monitor can also monitor hardware drops, we should allow
the user to control these as well.
Do that by adding SW and HW flags to these commands. If no flag is
specified, then only start / stop monitoring software drops. This is
done in order to maintain backward-compatibility with existing user
space applications.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In summary alert mode a notification is sent with a list of recent drop
reasons and a count of how many packets were dropped due to this reason.
To avoid expensive operations in the context in which packets are
dropped, each CPU holds an array whose number of entries is the maximum
number of drop reasons that can be encoded in the netlink notification.
Each entry stores the drop reason and a count. When a packet is dropped
the array is traversed and a new entry is created or the count of an
existing entry is incremented.
Later, in process context, the array is replaced with a newly allocated
copy and the old array is encoded in a netlink notification. To avoid
breaking user space, the notification includes the ancillary header,
which is 'struct net_dm_alert_msg' with number of entries set to '0'.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In a similar fashion to software drops, extend drop monitor to send
netlink events when packets are dropped by the underlying hardware.
The main difference is that instead of encoding the program counter (PC)
from which kfree_skb() was called in the netlink message, we encode the
hardware trap name. The two are mostly equivalent since they should both
help the user understand why the packet was dropped.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The drop monitor configuration (e.g., alert mode) is global, but user
will be able to enable monitoring of only software or hardware drops.
Therefore, ensure that monitoring of both software and hardware drops are
disabled before allowing drop monitor configuration to take place.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Export a function that can be invoked in order to report packets that
were dropped by the underlying hardware along with metadata.
Subsequent patches will add support for the different alert modes.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Like software drops, hardware drops also need the same type of per-CPU
data. Therefore, initialize it during module initialization and
de-initialize it during module exit.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently drop monitor only reports software drops to user space, but
subsequent patches are going to add support for hardware drops.
Like software drops, the per-CPU data of hardware drops needs to be
initialized and de-initialized upon module initialization and exit. To
avoid code duplication, break this code into separate functions, so that
these could be re-used for hardware drops.
No functional changes intended.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Previous patch made the length of the per-CPU skb drop list
configurable. Expose a counter that shows how many packets could not be
enqueued to this list.
This allows users determine the desired queue length.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In packet alert mode, each CPU holds a list of dropped skbs that need to
be processed in process context and sent to user space. To avoid
exhausting the system's memory the maximum length of this queue is
currently set to 1000.
Allow users to tune the length of this queue according to their needs.
The configured length is reported to user space when drop monitor
configuration is queried.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Users should be able to query the current configuration of drop monitor
before they start using it. Add a command to query the existing
configuration which currently consists of alert mode and packet
truncation length.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When sending dropped packets to user space it is not always necessary to
copy the entire packet as usually only the headers are of interest.
Allow user to specify the truncation length and add the original length
of the packet as additional metadata to the netlink message.
By default no truncation is performed.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
So far drop monitor supported only one alert mode in which a summary of
locations in which packets were recently dropped was sent to user space.
This alert mode is sufficient in order to understand that packets were
dropped, but lacks information to perform a more detailed analysis.
Add a new alert mode in which the dropped packet itself is passed to
user space along with metadata: The drop location (as program counter
and resolved symbol), ingress netdevice and drop timestamp. More
metadata can be added in the future.
To avoid performing expensive operations in the context in which
kfree_skb() is invoked (can be hard IRQ), the dropped skb is cloned and
queued on per-CPU skb drop list. Then, in process context the netlink
message is allocated, prepared and finally sent to user space.
The per-CPU skb drop list is limited to 1000 skbs to prevent exhausting
the system's memory. Subsequent patches will make this limit
configurable and also add a counter that indicates how many skbs were
tail dropped.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The next patch is going to add another alert mode in which the dropped
packet is notified to user space, instead of only a summary of recent
drops.
Abstract the differences between the modes by adding alert mode
operations. The operations are selected based on the currently
configured mode and associated with the probes and the work item just
before tracing starts.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, the configure command does not do anything but return an
error. Subsequent patches will enable the command to change various
configuration options such as alert mode and packet truncation.
Similar to other netlink-based configuration channels, make sure only
users with the CAP_NET_ADMIN capability set can execute this command.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The function reset_per_cpu_data() allocates and prepares a new skb for
the summary netlink alert message ('NET_DM_CMD_ALERT'). The new skb is
stored in the per-CPU 'data' variable and the old is returned.
The function is invoked during module initialization and from the
workqueue, before an alert is sent. This means that it is possible to
receive an alert with stale data, if we stopped tracing when the
hysteresis timer ('data->send_timer') was pending.
Instead of invoking the function during module initialization, invoke it
just before we start tracing and ensure we get a fresh skb.
This also allows us to remove the calls to initialize the timer and the
work item from the module initialization path, since both could have
been triggered by the error paths of reset_per_cpu_data().
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The timer and work item are currently initialized once during module
init, but subsequent patches will need to associate different functions
with the work item, based on the configured alert mode.
Allow subsequent patches to make that change by initializing and
de-initializing these objects during tracing enable and disable.
This also guarantees that once the request to disable tracing returns,
no more netlink notifications will be generated.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Subsequent patches will need to enable / disable tracing based on the
configured alerting mode.
Reduce the nesting level and prepare for the introduction of this
functionality by splitting the tracing enable / disable operations into
two different functions.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Each operation from user space should be protected by the global drop
monitor mutex. Use the pre_doit / post_doit hooks to take / release the
lock instead of doing it explicitly in each function.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add various extack messages to make drop_monitor more user friendly.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove multiple blank lines which are visually annoying and useless.
This suppresses the "Please don't use multiple blank lines" checkpatch
messages.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While 'per_cpu_dm_data' is a per-CPU variable, its 'skb' and
'send_timer' fields can be accessed concurrently by the CPU sending the
netlink notification to user space from the workqueue and the CPU
tracing kfree_skb(). This spinlock is meant to protect against that.
Document its scope and suppress the checkpatch message "spinlock_t
definition without comment".
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The 'trace_state_mutex' does not only protect the global 'trace_state'
variable, but also the global 'hw_stats_list'.
Subsequent patches are going add more operations from user space to
drop_monitor and these all need to be mutually exclusive.
Rename 'trace_state_mutex' to the more fitting 'net_dm_mutex' name and
document its scope.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The error code 'ENOTSUPP' is reserved for use with NFS. Use 'EOPNOTSUPP'
instead.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have MODULE_LICENCE("GPL*") inside which was used in the initial
scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add options to strictly validate messages and dump messages,
sometimes perhaps validating dump messages non-strictly may
be required, so add an option for that as well.
Since none of this can really be applied to existing commands,
set the options everwhere using the following spatch:
@@
identifier ops;
expression X;
@@
struct genl_ops ops[] = {
...,
{
.cmd = X,
+ .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
...
},
...
};
For new commands one should just not copy the .validate 'opt-out'
flags and thus get strict validation.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use setup_timer() instead of init_timer() to simplify the code.
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Final nlmsg_len field update must reflect inserted net_dm_drop_point
data.
This patch depends on previous patch:
"drop_monitor: add missing call to genlmsg_end"
Signed-off-by: Reiter Wolfgang <wr0112358@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Update nlmsg_len field with genlmsg_end to enable userspace processing
using nlmsg_next helper. Also adds error handling.
Signed-off-by: Reiter Wolfgang <wr0112358@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now genl_register_family() is the only thing (other than the
users themselves, perhaps, but I didn't find any doing that)
writing to the family struct.
In all families that I found, genl_register_family() is only
called from __init functions (some indirectly, in which case
I've add __init annotations to clarifly things), so all can
actually be marked __ro_after_init.
This protects the data structure from accidental corruption.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Instead of providing macros/inline functions to initialize
the families, make all users initialize them statically and
get rid of the macros.
This reduces the kernel code size by about 1.6k on x86-64
(with allyesconfig).
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Static family IDs have never really been used, the only
use case was the workaround I introduced for those users
that assumed their family ID was also their multicast
group ID.
Additionally, because static family IDs would never be
reserved by the generic netlink code, using a relatively
low ID would only work for built-in families that can be
registered immediately after generic netlink is started,
which is basically only the control family (apart from
the workaround code, which I also had to add code for so
it would reserve those IDs)
Thus, anything other than GENL_ID_GENERATE is flawed and
luckily not used except in the cases I mentioned. Move
those workarounds into a few lines of code, and then get
rid of GENL_ID_GENERATE entirely, making it more robust.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
An important information for the napi_poll tracepoint is knowing
the work done (packets processed) by the napi_poll() call. Add
both the work done and budget, as they are related.
Handle trace_napi_poll() param change in dropwatch/drop_monitor
and in python perf script netdev-times.py in backward compat way,
as python fortunately supports optional parameter handling.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Replace uses of get_cpu_var for address calculation through this_cpu_ptr.
Cc: netdev@vger.kernel.org
Cc: Eric Dumazet <edumazet@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
maxattr in genl_family should be used to save the max attribute
type, but not the max command type. Drop monitor doesn't support
any attributes, so we should leave it as zero.
Signed-off-by: David S. Miller <davem@davemloft.net>
Register generic netlink multicast groups as an array with
the family and give them contiguous group IDs. Then instead
of passing the global group ID to the various functions that
send messages, pass the ID relative to the family - for most
families that's just 0 because the only have one group.
This avoids the list_head and ID in each group, adding a new
field for the mcast group ID offset to the family.
At the same time, this allows us to prevent abusing groups
again like the quota and dropmon code did, since we can now
check that a family only uses a group it owns.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This doesn't really change anything, but prepares for the
next patch that will change the APIs to pass the group ID
within the family, rather than the global group ID.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The drop monitor code is abusing the genetlink API and is
statically using the generic netlink multicast group 1, even
if that group belongs to somebody else (which it invariably
will, since it's not reserved.)
Make the drop monitor code use the proper APIs to reserve a
group ID, but also reserve the group id 1 in generic netlink
code to preserve the userspace API. Since drop monitor can
be a module, don't clear the bit for it on unregistration.
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As suggested by David Miller, make genl_register_family_with_ops()
a macro and pass only the array, evaluating ARRAY_SIZE() in the
macro, this is a little safer.
The openvswitch has some indirection, assing ops/n_ops directly in
that code. This might ultimately just assign the pointers in the
family initializations, saving the struct genl_family_and_ops and
code (once mcast groups are handled differently.)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that genl_ops are no longer modified in place when
registering, they can be made const. This patch was done
mostly with spatch:
@@
identifier ops;
@@
+const
struct genl_ops ops[] = {
...
};
(except the struct thing in net/openvswitch/datapath.c)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
So far, only net_device * could be passed along with netdevice notifier
event. This patch provides a possibility to pass custom structure
able to provide info that event listener needs to know.
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
v2->v3: fix typo on simeth
shortened dev_getter
shortened notifier_info struct name
v1->v2: fix notifier_call parameter in call_netdevice_notifier()
Signed-off-by: David S. Miller <davem@davemloft.net>
drop_monitor calls several sleeping functions while in atomic context.
BUG: sleeping function called from invalid context at mm/slub.c:943
in_atomic(): 1, irqs_disabled(): 0, pid: 2103, name: kworker/0:2
Pid: 2103, comm: kworker/0:2 Not tainted 3.5.0-rc1+ #55
Call Trace:
[<ffffffff810697ca>] __might_sleep+0xca/0xf0
[<ffffffff811345a3>] kmem_cache_alloc_node+0x1b3/0x1c0
[<ffffffff8105578c>] ? queue_delayed_work_on+0x11c/0x130
[<ffffffff815343fb>] __alloc_skb+0x4b/0x230
[<ffffffffa00b0360>] ? reset_per_cpu_data+0x160/0x160 [drop_monitor]
[<ffffffffa00b022f>] reset_per_cpu_data+0x2f/0x160 [drop_monitor]
[<ffffffffa00b03ab>] send_dm_alert+0x4b/0xb0 [drop_monitor]
[<ffffffff810568e0>] process_one_work+0x130/0x4c0
[<ffffffff81058249>] worker_thread+0x159/0x360
[<ffffffff810580f0>] ? manage_workers.isra.27+0x240/0x240
[<ffffffff8105d403>] kthread+0x93/0xa0
[<ffffffff816be6d4>] kernel_thread_helper+0x4/0x10
[<ffffffff8105d370>] ? kthread_freezable_should_stop+0x80/0x80
[<ffffffff816be6d0>] ? gs_change+0xb/0xb
Rework the logic to call the sleeping functions in right context.
Use standard timer/workqueue api to let system chose any cpu to perform
the allocation and netlink send.
Also avoid a loop if reset_per_cpu_data() cannot allocate memory :
use mod_timer() to wait 1/10 second before next try.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that we have module alias macros for generic netlink families, lets use
those to mark modules with the appropriate family names for loading
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: David Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
When I first wrote drop monitor I wrote it to just build monolithically. There
is no reason it can't be built modularly as well, so lets give it that
flexibiity.
I've tested this by building it as both a module and monolithically, and it
seems to work quite well
Change notes:
v2)
* fixed for_each_present_cpu loops to be more correct as per Eric D.
* Converted exit path failures to BUG_ON as per Ben H.
v3)
* Converted del_timer to del_timer_sync to close race noted by Ben H.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Ben Hutchings <bhutchings@solarflare.com>
Reviewed-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Ido Schimmel