Merge tag 'locking-urgent-2022-06-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull lockdep fix from Thomas Gleixner: "A RT fix for lockdep. lockdep invokes prandom_u32() to create cookies. This worked until prandom_u32() was switched to the real random generator, which takes a spinlock for extraction, which does not work on RT when invoked from atomic contexts. lockdep has no requirement for real random numbers and it turns out sched_clock() is good enough to create the cookie. That works everywhere and is faster" * tag 'locking-urgent-2022-06-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/lockdep: Use sched_clock() for random numbers

Linus Torvalds committed 4 years ago

Commit 4afb6512 parents 36da9f5 4051a811 file · +1 −1Browse files

Unified · Split

kernel/locking/lockdep.c+1−1

@@ -5432,7 +5432,7 @@ static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock) · 5431 unmodified lines
5432	5432	* be guessable and still allows some pin nesting in
5433	5433	* our u32 pin_count.
5434	5434	*/
5435		− cookie.val = 1 + (prandom_u32() >> 16);
	5435	+ cookie.val = 1 + (sched_clock() & 0xffff);
5436	5436	hlock->pin_count += cookie.val;
5437	5437	return cookie;
5438	5438	}