From 6939f667247ed792535c0697a99f600d6770f127 Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Wed, 13 Sep 2017 12:09:28 -0600 Subject: [PATCH] Btrfs: fix confusing worker helper info in stacktrace We've seen the following backtrace stack in ftrace or dmesg log, kworker/u16:10-4244 [000] 241942.480955: function: btrfs_put_ordered_extent kworker/u16:10-4244 [000] 241942.480956: kernel_stack: => finish_ordered_fn (ffffffffa0384475) => btrfs_scrubparity_helper (ffffffffa03ca577) <-----"incorrect" => btrfs_freespace_write_helper (ffffffffa03ca98e) <-----"correct" => process_one_work (ffffffff81117b2f) => worker_thread (ffffffff81118c2a) => kthread (ffffffff81121de0) => ret_from_fork (ffffffff81d7087a) btrfs_freespace_write_helper is actually calling normal_worker_helper instead of btrfs_scrubparity_helper, so somehow kernel has parsed the incorrect function address while unwinding the stack, btrfs_scrubparity_helper really shouldn't be shown up. It's caused by compiler doing inline for our helper function, adding a noinline tag can fix that. Signed-off-by: Liu Bo Reviewed-by: David Sterba [ use noinline_for_stack ] Signed-off-by: David Sterba --- fs/btrfs/async-thread.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c index e00c8a9fd5bb..d5540749f0e5 100644 --- a/fs/btrfs/async-thread.c +++ b/fs/btrfs/async-thread.c @@ -67,7 +67,7 @@ struct btrfs_workqueue { static void normal_work_helper(struct btrfs_work *work); #define BTRFS_WORK_HELPER(name) \ -void btrfs_##name(struct work_struct *arg) \ +noinline_for_stack void btrfs_##name(struct work_struct *arg) \ { \ struct btrfs_work *work = container_of(arg, struct btrfs_work, \ normal_work); \