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| author | Peter Zijlstra <peterz@infradead.org> | 2020-08-18 16:57:36 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-09-01 10:58:03 +0300 |
| commit | 70d932985757fbe978024db313001218e9f8fe5c (patch) | |
| tree | 66e9c13a3877d35009421dd0aa19a13d2d06450a /kernel/power/suspend.c | |
| parent | f75aef392f869018f78cfedf3c320a6b3fcfda6b (diff) | |
| download | linux-70d932985757fbe978024db313001218e9f8fe5c.tar.xz | |
notifier: Fix broken error handling pattern
The current notifiers have the following error handling pattern all
over the place:
int err, nr;
err = __foo_notifier_call_chain(&chain, val_up, v, -1, &nr);
if (err & NOTIFIER_STOP_MASK)
__foo_notifier_call_chain(&chain, val_down, v, nr-1, NULL)
And aside from the endless repetition thereof, it is broken. Consider
blocking notifiers; both calls take and drop the rwsem, this means
that the notifier list can change in between the two calls, making @nr
meaningless.
Fix this by replacing all the __foo_notifier_call_chain() functions
with foo_notifier_call_chain_robust() that embeds the above pattern,
but ensures it is inside a single lock region.
Note: I switched atomic_notifier_call_chain_robust() to use
the spinlock, since RCU cannot provide the guarantee
required for the recovery.
Note: software_resume() error handling was broken afaict.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20200818135804.325626653@infradead.org
Diffstat (limited to 'kernel/power/suspend.c')
| -rw-r--r-- | kernel/power/suspend.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 8b1bb5ee7e5d..32391acc806b 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -342,18 +342,16 @@ static int suspend_test(int level) */ static int suspend_prepare(suspend_state_t state) { - int error, nr_calls = 0; + int error; if (!sleep_state_supported(state)) return -EPERM; pm_prepare_console(); - error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls); - if (error) { - nr_calls--; - goto Finish; - } + error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND); + if (error) + goto Restore; trace_suspend_resume(TPS("freeze_processes"), 0, true); error = suspend_freeze_processes(); @@ -363,8 +361,8 @@ static int suspend_prepare(suspend_state_t state) suspend_stats.failed_freeze++; dpm_save_failed_step(SUSPEND_FREEZE); - Finish: - __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL); + pm_notifier_call_chain(PM_POST_SUSPEND); + Restore: pm_restore_console(); return error; } |