trace/fgraph: Fix error handling

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[ Upstream commit ab1396af75 ]

Commit edede7a6dc ("trace/fgraph: Fix the warning caused by missing
unregister notifier") added a call to unregister the PM notifier if
register_ftrace_graph() failed. It does so unconditionally. However,
the PM notifier is only registered with the first call to
register_ftrace_graph(). If the first registration was successful and
a subsequent registration failed, the notifier is now unregistered even
if ftrace graphs are still registered.

Fix the problem by only unregistering the PM notifier during error handling
if there are no active fgraph registrations.

Fixes: edede7a6dc ("trace/fgraph: Fix the warning caused by missing unregister notifier")
Closes: https://lore.kernel.org/all/63b0ba5a-a928-438e-84f9-93028dd72e54@roeck-us.net/
Cc: Ye Weihua <yeweihua4@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20250906050618.2634078-1-linux@roeck-us.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Guenter Roeck 2025-09-05 22:06:18 -07:00 • committed by Greg Kroah-Hartman

parent 2bc2060856

commit 35601bc50d

1 changed files with 2 additions and 1 deletions

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kernel/trace/fgraph.c

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