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| author |   Hans de Goede <hdegoede@redhat.com> | 2012-05-22 11:40:26 +0200 |
|---|---|---|
| committer |   Wim Van Sebroeck <wim@iguana.be> | 2012-05-30 07:55:23 +0200 |
| commit | f4e9c82f64b524314a390b13d3ba7d483f09258f (patch) | |
| tree | 82d688ae7782234dc01c6a340596bac21531aae4 /drivers/watchdog/watchdog_core.c | |
| parent | watchdog: watchdog_dev: Rewrite wrapper code (diff) | |
| download | linux-dev-f4e9c82f64b524314a390b13d3ba7d483f09258f.tar.xz linux-dev-f4e9c82f64b524314a390b13d3ba7d483f09258f.zip | |
watchdog: Add Locking support
This patch fixes some potential multithreading issues, despite only
allowing one process to open the /dev/watchdog device, we can still get
called multiple times at the same time, since a program could be using thread,
or could share the fd after a fork.
This causes 2 potential problems:
1) watchdog_start / open do an unlocked test_n_set / test_n_clear,
if these 2 race, the watchdog could be stopped while the active
bit indicates it is running or visa versa.
2) Most watchdog_dev drivers probably assume that only one
watchdog-op will get called at a time, this is not necessary
true atm.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'drivers/watchdog/watchdog_core.c')
| -rw-r--r-- | drivers/watchdog/watchdog_core.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c index 86a57673abf9..6aa46a90ff02 100644 --- a/drivers/watchdog/watchdog_core.c +++ b/drivers/watchdog/watchdog_core.c @@ -79,6 +79,7 @@ int watchdog_register_device(struct watchdog_device *wdd) * corrupted in a later stage then we expect a kernel panic! */ + mutex_init(&wdd->lock); id = ida_simple_get(&watchdog_ida, 0, MAX_DOGS, GFP_KERNEL); if (id < 0) return id; |