Commit Graph

28 Commits

Author SHA1 Message Date
Niklas Cassel 8d5755b3f7 watchdog: softdog: fire watchdog even if softirqs do not get to run
Checking for timer expiration is done from the softirq TIMER_SOFTIRQ.

Since commit 4cd13c21b2 ("softirq: Let ksoftirqd do its job"),
pending softirqs are no longer always handled immediately, instead,
if there are pending softirqs, and ksoftirqd is in state TASK_RUNNING,
the handling of the softirqs are deferred, and are instead supposed
to be handled by ksoftirqd, when ksoftirqd gets scheduled.

If a user space process with a real-time policy starts to misbehave
by never relinquishing the CPU while ksoftirqd is in state TASK_RUNNING,
what will happen is that all softirqs will get deferred, while ksoftirqd,
which is supposed to handle the deferred softirqs, will never get to run.

To make sure that the watchdog is able to fire even when we do not get
to run softirqs, replace the timers with hrtimers.

Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-03-01 06:15:10 -08:00
Wolfram Sang 4cbc69023a watchdog: softdog: make pretimeout support a compile option
It occurred to me that the panic pretimeout governor will stall the
softdog, because it is purely software which simply breaks when the
kernel panics. Testing governors with the softdog on the other hand is
really useful, so make this feature a compile time option which nees to
be enabled explicitly. This also removes the overhead if pretimeout
support is not used because it will now be compiled away (saving ~10% on
ARM32).

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-02-24 14:00:23 -08:00
Wolfram Sang 2accf32078 watchdog: softdog: implement pretimeout support
Give devices which do not have hardware support for pretimeout at least a
software version of it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
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>
2016-10-08 10:27:27 +02:00
Julia Lawall 85f15cfc21 watchdog: constify watchdog_ops structures
Check for watchdog_ops structures that are only stored in the ops field of
a watchdog_device structure.  This field is declared const, so watchdog_ops
structures that have this property can be declared as const also.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r disable optional_qualifier@
identifier i;
position p;
@@
static struct watchdog_ops i@p = { ... };

@ok@
identifier r.i;
struct watchdog_device e;
position p;
@@
e.ops = &i@p;

@bad@
position p != {r.p,ok.p};
identifier r.i;
struct watchdog_ops e;
@@
e@i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
 struct watchdog_ops i = { ... };
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.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>
2016-09-24 08:50:10 +02:00
Wolfram Sang 4a23e2bf03 watchdog: softdog: improve coding style
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.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>
2016-07-17 20:54:52 +02:00
Wolfram Sang 61a21274c9 watchdog: softdog: drop superfluous set_timeout callback
If we leave set_timeout empty, the core will do exactly what is
implemented here anyway.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.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>
2016-07-17 20:54:49 +02:00
Wolfram Sang e65c5825c6 watchdog: softdog: sort includes to avoid duplicates
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.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>
2016-07-17 20:54:45 +02:00
Wolfram Sang 44ba0f04af watchdog: softdog: remove forward declaration
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.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>
2016-07-17 20:54:42 +02:00
Wolfram Sang 0efc70b823 watchdog: softdog: consistently use softdog_ prefix
And move module_init/exit to the proper place while here.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.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>
2016-07-17 20:54:38 +02:00
Wolfram Sang e8cf96abba watchdog: softdog: use watchdog core to init timeout value
Error string and comment say we fall back to a default, but in reality
we bailed out. Refactor the code to use the core helper which then
matches the described behaviour. While updating the init message anyhow,
shorten it while we are here; no need for versioning there as well and
the name is already given via pr_fmt.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.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>
2016-07-17 20:54:34 +02:00
Wolfram Sang 9c963ba0e0 watchdog: softdog: remove obsolete comments
The history is obsolete, especially since we switched to watchdog
framework. The section markers also don't make sense anymore given
the small size of the driver.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.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>
2016-07-17 20:54:31 +02:00
Li RongQing 5889f06bd3 watchdog: refuse to unload softdog module when its timer is running
the softdog has static variables which are accessed if its timer is
still running after the driver is unloaded. and lead to crash:

   $modprobe softdog
   $echo 1 >/dev/watchdog
   $modprobe -r softdog

   CPU 20 Unable to handle kernel paging request at virtual address
   Oops[#1]:
   CPU: 20 PID: 0 Comm: swapper/20 Not tainted 4.1.13-WR8.0.0.0_standard
   ...
   Modules linked in: [last unloaded: softdog]
    ....
   Call Trace:
   [<ffffffff801e142c>] cascade+0x34/0xb0
   [<ffffffff801e1964>] run_timer_softirq+0x30c/0x368
   [<ffffffff80181044>] __do_softirq+0x1ec/0x418
   [<ffffffff801815d0>] irq_exit+0x90/0x98
   [<ffffffff8010749c>] plat_irq_dispatch+0xa4/0x140
   [<ffffffff80152740>] ret_from_irq+0x0/0x4
   [<ffffffff801529e0>] __r4k_wait+0x20/0x40
   [<ffffffff801c2278>] cpu_startup_entry+0x2a0/0x368
   [<ffffffff8015fa64>] start_secondary+0x444/0x4d8

add the module ref when timer is running to avoid to unload the softdog
module

Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2015-12-27 21:02:21 +01:00
Damien Riegel 84ebcc17f2 watchdog: softdog: use core reboot notifier
Get rid of the custom reboot notifier block registration and use the one
provided by the watchdog core.

Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirlinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2015-12-13 15:56:06 +01:00
Jingoo Han 5f5e19093b watchdog: fix checkpatch warnings and error
Fix the following checkpatch warnings and error:
  WARNING: quoted string split across lines
  WARNING: braces {} are not necessary for single statement blocks
  WARNING: __initdata should be placed after ibmasr_id_table[]
  WARNING: please, no space before tabs
  ERROR: do not initialise statics to 0 or NULL

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2014-03-31 13:31:06 +02:00
Guenter Roeck 9539210e17 watchdog: Drop unnecessary include of miscdevice.h
After commit 487722cf2 (watchdog: Get rid of MODULE_ALIAS_MISCDEV
statements) the affected drivers no longer need to include miscdevice.h.
Only exception is rt2880_wdt.c which never needed it.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2013-12-10 08:48:09 +01:00
Jean Delvare 487722cf2d watchdog: Get rid of MODULE_ALIAS_MISCDEV statements
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR)
and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements.

Either the device is enumerated and the driver already has a module
alias (e.g. PCI, USB etc.) that will get the right driver loaded
automatically.

Or the device is not enumerated and loading its driver will lead to
more or less intrusive hardware poking. Such hardware poking should be
limited to a bare minimum, so the user should really decide which
drivers should be tried and in what order. Trying them all in
arbitrary order can't do any good.

On top of that, loading that many drivers at once bloats the kernel
log. Also many drivers will stay loaded afterward, bloating the output
of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets
loaded as a dependency) can't even be unloaded!

If defining char-major-10-130 is needed then it should happen in
user-space.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Jim Cromie <jim.cromie@gmail.com>
2013-11-17 19:38:13 +01:00
Kim, Milo 086f3ec187 watchdog: softdog: remove replaceable ping operation
In watchdog_ping(), 'start' is called automatically when 'ping' function call
is not configured.
Softdog driver has same handling in both cases - start and ping, so 'ping' OPS
can be removed.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2013-07-11 22:19:30 +02:00
Alan Cox a5132cafc0 watchdog: softdog: convert to watchdog core
Convert softdog.c to the new watchdog API.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-03-27 20:07:21 +02:00
Wim Van Sebroeck 86a1e1896c watchdog: nowayout is bool
nowayout is actually a boolean value.
So make it bool for all watchdog device drivers.

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-03-27 20:06:02 +02:00
Joe Perches 27c766aaac watchdog: Use pr_<fmt> and pr_<level>
Use the current logging styles.

Make sure all output has a prefix.
Add missing newlines.
Remove now unnecessary PFX, NAME, and miscellaneous other #defines.
Coalesce formats.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2012-03-27 19:59:26 +02:00
Anithra P Janakiraman 7fff4beb31 watchdog: softdog.c: enhancement to optionally invoke panic instead of reboot on timer expiry
This is needed for determining the reason for failure when a softdog
timeout occurs.

We use softdog to watch for critical application failures and at the
minimum a snapshot of the system would help to determine the cause.  In
such a scenario the application could fail but there isn't a softlockup as
such, hence the detect softlockup feature does not help.

The patch adds a module parameter soft_panic which when set to 1 causes
softdog to invoke panic instead of reboot when the softdog timer expires. 
By invoking panic we execute kdump if it is configured and the vmcore
generated by kdump should provide atleast a minimal idea of the reason for
failure.

Based on an original patch by Ken Sugawara <sugaken.r3@gmail.com>
Signed-off-by: Anithra P J <anithra@linux.vnet.ibm.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2011-03-29 11:56:22 +00:00
Wim Van Sebroeck 5f3b27569f watchdog: cleanup spaces before tabs
cleanup spaces before tabs in drivers/watchdog/

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2011-03-15 16:02:27 +00:00
Wim Van Sebroeck a77dba7e44 [WATCHDOG] Some more general cleanup
Clean-up the watchdog drivers so that checkpatch.pl get's happy...

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2009-06-18 07:30:30 +00:00
Wim Van Sebroeck 143a2e54bf [WATCHDOG] More coding-style and trivial clean-up
Some more cleaning-up of the watchdog drivers.

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2009-03-25 09:07:04 +00:00
Alan Cox 29fa0586de [PATCH] Switch all my contributions stuff to a single common address
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2008-10-28 19:16:11 +00:00
Wim Van Sebroeck 0c06090c94 [WATCHDOG] Coding style - Indentation - part 2
This brings the watchdog drivers into line with coding style.
This patch takes cares of the indentation as described in chapter 1.
Main changes:
* Re-structure the ioctl switch call for all drivers as follows:
	switch (cmd) {
	case WDIOC_GETSUPPORT:
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	case WDIOC_GETTEMP:
	case WDIOC_SETOPTIONS:
	case WDIOC_KEEPALIVE:
	case WDIOC_SETTIMEOUT:
	case WDIOC_GETTIMEOUT:
	case WDIOC_GETTIMELEFT:
	default:
	}

This to make the migration from the drivers to the uniform watchdog
device driver easier in the future.

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2008-08-06 13:21:09 +00:00
Alan Cox f92d3749d7 [WATCHDOG 47/57] softdog: clean up, coding style and switch to unlocked_ioctl
Review and switch to unlocked_ioctl

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2008-06-21 15:40:42 +00:00
Wim Van Sebroeck b7e04f8c61 mv watchdog tree under drivers
move watchdog tree from drivers/char/watchdog to drivers/watchdog.

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2007-10-18 10:39:03 +00:00