commit 605b0487f0bc1ae9963bf52ece0f5c8055186f81 upstream.
Mark Syms has reported seeing tasks that are stuck waiting in
find_insert_glock. It turns out that struct lm_lockname contains four padding
bytes on 64-bit architectures that function glock_waitqueue doesn't skip when
hashing the glock name. As a result, we can end up waking up the wrong
waitqueue, and the waiting tasks may be stuck forever.
Fix that by using ht_parms.key_len instead of sizeof(struct lm_lockname) for
the key length.
Reported-by: Mark Syms <mark.syms@xxxxxxxxxx>
Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
Signed-off-by: Bob Peterson <rpeterso@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v4.14+
---
fs/gfs2/glock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index f66773c71bcde..d32964cd11176 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -107,7 +107,7 @@ static int glock_wake_function(wait_queue_entry_t *wait, unsigned int mode,
static wait_queue_head_t *glock_waitqueue(struct lm_lockname *name)
{
- u32 hash = jhash2((u32 *)name, sizeof(*name) / 4, 0);
+ u32 hash = jhash2((u32 *)name, ht_parms.key_len / 4, 0);
return glock_wait_table + hash_32(hash, GLOCK_WAIT_TABLE_BITS);
}
--
2.20.1
