diff options
| author | Byungchul Park <byungchul.park@lge.com> | 2017-08-14 16:00:52 +0900 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-08-14 12:52:17 +0200 |
| commit | 907dc16d7e23ec81a126c9585435494fa1b3a4b7 (patch) | |
| tree | 31b53da542b0fa6cb863c06a39daeed055372acb | |
| parent | a10b5c564741cd3b6708f085a1fa892b63c2063d (diff) | |
| download | linux-907dc16d7e23ec81a126c9585435494fa1b3a4b7.tar.gz linux-907dc16d7e23ec81a126c9585435494fa1b3a4b7.tar.bz2 linux-907dc16d7e23ec81a126c9585435494fa1b3a4b7.zip | |
locking/lockdep: Fix the rollback and overwrite detection logic in crossrelease
As Boqun Feng pointed out, current->hist_id should be aligned with the
latest valid xhlock->hist_id so that hist_id_save[] storing current->hist_id
can be comparable with xhlock->hist_id. Fix it.
Additionally, the condition for overwrite-detection should be the
opposite. Fix the code and the comments as well.
<- direction to visit
hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh (h: history)
^^ ^
|| start from here
|previous entry
current entry
Reported-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: kernel-team@lge.com
Cc: kirill@shutemov.name
Cc: linux-mm@kvack.org
Cc: npiggin@gmail.com
Cc: walken@google.com
Cc: willy@infradead.org
Link: http://lkml.kernel.org/r/1502694052-16085-3-git-send-email-byungchul.park@lge.com
[ Improve the comments some more. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | kernel/locking/lockdep.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 257931e2fbbe..66011c9f5df3 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4853,7 +4853,7 @@ static void add_xhlock(struct held_lock *hlock) /* Initialize hist_lock's members */ xhlock->hlock = *hlock; - xhlock->hist_id = current->hist_id++; + xhlock->hist_id = ++current->hist_id; xhlock->trace.nr_entries = 0; xhlock->trace.max_entries = MAX_XHLOCK_TRACE_ENTRIES; @@ -5029,12 +5029,12 @@ static void commit_xhlocks(struct cross_lock *xlock) break; /* - * Filter out the cases that the ring buffer was - * overwritten and the previous entry has a bigger - * hist_id than the following one, which is impossible - * otherwise. + * Filter out the cases where the ring buffer was + * overwritten and the current entry has a bigger + * hist_id than the previous one, which is impossible + * otherwise: */ - if (unlikely(before(xhlock->hist_id, prev_hist_id))) + if (unlikely(before(prev_hist_id, xhlock->hist_id))) break; prev_hist_id = xhlock->hist_id; |