hrtimer: Don't dereference the hrtimer pointer after the callback

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A hrtimer can be released in its callback, but lockdep_hrtimer_exit()
dereferences the pointer after the callback returns, i.e. a potential use
after free.

Retrieve the context in which the hrtimer expires before the callback is
invoked and use it in lockdep_hrtimer_exit().

Fixes: 40db173965 ("lockdep: Add hrtimer context tracing bits")
Reported-by: syzbot+62c155c276e580cfb606@syzkaller.appspotmail.com
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200331201849.fkp2siy3vcdqvqlz@linutronix.de

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Sebastian Andrzej Siewior 2020-03-31 22:18:49 +02:00 • committed by Thomas Gleixner

parent 42595ce90b

commit 73d20564e0

2 changed files with 19 additions and 13 deletions

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25

include/linux/irqflags.h

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5

kernel/time/hrtimer.c

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