Messages in this thread Patch in this message | | | Date | Mon, 1 Feb 2021 12:23:39 +0100 | From | Peter Zijlstra <> | Subject | Re: corrupted pvqspinlock in htab_map_update_elem |
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On Mon, Feb 01, 2021 at 10:50:58AM +0100, Peter Zijlstra wrote:
> > queued_spin_unlock arch/x86/include/asm/qspinlock.h:56 [inline] > > lockdep_unlock+0x10e/0x290 kernel/locking/lockdep.c:124 > > debug_locks_off_graph_unlock kernel/locking/lockdep.c:165 [inline] > > print_usage_bug kernel/locking/lockdep.c:3710 [inline] > > Ha, I think you hit a bug in lockdep.
Something like so I suppose.
--- Subject: locking/lockdep: Avoid unmatched unlock From: Peter Zijlstra <peterz@infradead.org> Date: Mon Feb 1 11:55:38 CET 2021
Commit f6f48e180404 ("lockdep: Teach lockdep about "USED" <- "IN-NMI" inversions") overlooked that print_usage_bug() releases the graph_lock and called it without the graph lock held.
Fixes: f6f48e180404 ("lockdep: Teach lockdep about "USED" <- "IN-NMI" inversions") Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/locking/lockdep.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -3773,7 +3773,7 @@ static void print_usage_bug(struct task_struct *curr, struct held_lock *this, enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) { - if (!debug_locks_off_graph_unlock() || debug_locks_silent) + if (!debug_locks_off() || debug_locks_silent) return; pr_warn("\n"); @@ -3814,6 +3814,7 @@ valid_state(struct task_struct *curr, st enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) { if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) { + graph_unlock() print_usage_bug(curr, this, bad_bit, new_bit); return 0; }
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