From ac0c7cf8be00f269f82964cf7b144ca3edc5dbc4 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Fri, 6 Jan 2017 14:12:51 +0100 Subject: btrfs: fix crash when tracepoint arguments are freed by wq callbacks Enabling btrfs tracepoints leads to instant crash, as reported. The wq callbacks could free the memory and the tracepoints started to dereference the members to get to fs_info. The proposed fix https://marc.info/?l=linux-btrfs&m=148172436722606&w=2 removed the tracepoints but we could preserve them by passing only the required data in a safe way. Fixes: bc074524e123 ("btrfs: prefix fsid to all trace events") CC: stable@vger.kernel.org # 4.8+ Reported-by: Sebastian Andrzej Siewior Reviewed-by: Qu Wenruo Signed-off-by: David Sterba --- include/trace/events/btrfs.h | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) (limited to 'include') diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h index c14bed4ab097..b09225c77676 100644 --- a/include/trace/events/btrfs.h +++ b/include/trace/events/btrfs.h @@ -1157,22 +1157,26 @@ DECLARE_EVENT_CLASS(btrfs__work, __entry->func, __entry->ordered_func, __entry->ordered_free) ); -/* For situiations that the work is freed */ +/* + * For situiations when the work is freed, we pass fs_info and a tag that that + * matches address of the work structure so it can be paired with the + * scheduling event. + */ DECLARE_EVENT_CLASS(btrfs__work__done, - TP_PROTO(struct btrfs_work *work), + TP_PROTO(struct btrfs_fs_info *fs_info, void *wtag), - TP_ARGS(work), + TP_ARGS(fs_info, wtag), TP_STRUCT__entry_btrfs( - __field( void *, work ) + __field( void *, wtag ) ), - TP_fast_assign_btrfs(btrfs_work_owner(work), - __entry->work = work; + TP_fast_assign_btrfs(fs_info, + __entry->wtag = wtag; ), - TP_printk_btrfs("work->%p", __entry->work) + TP_printk_btrfs("work->%p", __entry->wtag) ); DEFINE_EVENT(btrfs__work, btrfs_work_queued, @@ -1191,9 +1195,9 @@ DEFINE_EVENT(btrfs__work, btrfs_work_sched, DEFINE_EVENT(btrfs__work__done, btrfs_all_work_done, - TP_PROTO(struct btrfs_work *work), + TP_PROTO(struct btrfs_fs_info *fs_info, void *wtag), - TP_ARGS(work) + TP_ARGS(fs_info, wtag) ); DEFINE_EVENT(btrfs__work, btrfs_ordered_sched, -- cgit v1.2.3