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authorPeter Zijlstra <peterz@infradead.org>2020-08-18 16:57:36 +0300
committerIngo Molnar <mingo@kernel.org>2020-09-01 10:58:03 +0300
commit70d932985757fbe978024db313001218e9f8fe5c (patch)
tree66e9c13a3877d35009421dd0aa19a13d2d06450a /kernel/power/suspend.c
parentf75aef392f869018f78cfedf3c320a6b3fcfda6b (diff)
downloadlinux-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.c14
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;
}