From 70d932985757fbe978024db313001218e9f8fe5c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 18 Aug 2020 15:57:36 +0200 Subject: 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) Signed-off-by: Ingo Molnar Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20200818135804.325626653@infradead.org --- tools/power/pm-graph/sleepgraph.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/power/pm-graph') diff --git a/tools/power/pm-graph/sleepgraph.py b/tools/power/pm-graph/sleepgraph.py index 46ff97e909c6..1bc36a1db14f 100755 --- a/tools/power/pm-graph/sleepgraph.py +++ b/tools/power/pm-graph/sleepgraph.py @@ -171,7 +171,7 @@ class SystemValues: tracefuncs = { 'sys_sync': {}, 'ksys_sync': {}, - '__pm_notifier_call_chain': {}, + 'pm_notifier_call_chain_robust': {}, 'pm_prepare_console': {}, 'pm_notifier_call_chain': {}, 'freeze_processes': {}, -- cgit v1.2.3