From 28393888c59873efe912c4634f20f6bce3373588 Mon Sep 17 00:00:00 2001 From: Pranith Kumar K Date: Wed, 9 Nov 2016 13:07:25 +0530 Subject: performance/open-behind: Avoid deadlock in statedump Problem: open-behind is taking fd->lock then inode->lock where as statedump is taking inode->lock then fd->lock, so it is leading to deadlock In open-behind, following code exists: void ob_fd_free (ob_fd_t *ob_fd) { loc_wipe (&ob_fd->loc); <<--- this takes (inode->lock) ....... } int ob_wake_cbk (call_frame_t *frame, void *cookie, xlator_t *this, int op_ret, int op_errno, fd_t *fd_ret, dict_t *xdata) { ....... LOCK (&fd->lock); <<---- fd->lock { ....... __fd_ctx_del (fd, this, NULL); ob_fd_free (ob_fd); <<<--------------- } UNLOCK (&fd->lock); ....... } ================================================================= In statedump this code exists: inode_dump (inode_t *inode, char *prefix) { ....... ret = TRY_LOCK(&inode->lock); <<---- inode->lock ....... fd_ctx_dump (fd, prefix); <<<----- ....... } fd_ctx_dump (fd_t *fd, char *prefix) { ....... LOCK (&fd->lock); <<<------------------ this takes fd-lock { ....... } Fix: Make sure open-behind doesn't call ob_fd_free() inside fd->lock BUG: 1393259 Change-Id: I4abdcfc5216270fa1e2b43f7b73445f49e6d6e6e Signed-off-by: Pranith Kumar K Reviewed-on: http://review.gluster.org/15808 Smoke: Gluster Build System NetBSD-regression: NetBSD Build System CentOS-regression: Gluster Build System Reviewed-by: Poornima G Reviewed-by: Raghavendra G --- xlators/performance/open-behind/src/open-behind.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'xlators') diff --git a/xlators/performance/open-behind/src/open-behind.c b/xlators/performance/open-behind/src/open-behind.c index 00e8906910a..d6dcf6fbc58 100644 --- a/xlators/performance/open-behind/src/open-behind.c +++ b/xlators/performance/open-behind/src/open-behind.c @@ -154,13 +154,16 @@ ob_wake_cbk (call_frame_t *frame, void *cookie, xlator_t *this, if (op_ret < 0) { /* mark fd BAD for ever */ ob_fd->op_errno = op_errno; + ob_fd = NULL; /*shouldn't be freed*/ } else { __fd_ctx_del (fd, this, NULL); - ob_fd_free (ob_fd); } } UNLOCK (&fd->lock); + if (ob_fd) + ob_fd_free (ob_fd); + list_for_each_entry_safe (stub, tmp, &list, list) { list_del_init (&stub->list); -- cgit