4.19-stable review patch. If anyone has any objections, please let me know.
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From: Andreas Gruenbacher agruenba@redhat.com
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@citrix.com Signed-off-by: Andreas Gruenbacher agruenba@redhat.com Signed-off-by: Bob Peterson rpeterso@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/gfs2/glock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -107,7 +107,7 @@ static int glock_wake_function(wait_queu
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); }