s390/debug: Fix race between debug area resize and event logging

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Trace functions check for non-NULL id->areas without lock to minimize
overhead. This opens a race window where a NULL pointer dereference
occurs if id->areas is set to NULL (e.g. via echo 0 > ../pages) after
the check and before id->lock is taken.

Fix this by rechecking id->areas under lock.

Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

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Mikhail Zaslonko 2026-09-03 15:07:33 +02:00 • committed by Vasily Gorbik

parent 22d4210bf9

commit 0945285e6c

1 changed files with 20 additions and 7 deletions

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arch/s390/kernel/debug.c

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