Commit-ID: b5230b56ee6caeb27cedb7753c0c319646383bb4 Gitweb: http://git.kernel.org/tip/b5230b56ee6caeb27cedb7753c0c319646383bb4 Author: Li Zefan <lizf@xxxxxxxxxxxxxx> AuthorDate: Wed, 25 Mar 2009 17:19:33 +0800 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Tue, 31 Mar 2009 17:26:59 +0200 blktrace: fix a race when creating blk_tree_root in debugfs t1 t2 ------ ------ do_blk_trace_setup() do_blk_trace_setup() if (!blk_tree_root) { if (!blk_tree_root) blk_tree_root = create_dir() blk_tree_root = create_dir(); (now blk_tree_root == NULL) ... dir = create_dir(name, blk_tree_root); Due to this race, t1 will create 'dir' in /debugfs but not /debugfs/block. Signed-off-by: Li Zefan <lizf@xxxxxxxxxxxxxx> Acked-by: Jens Axboe <jens.axboe@xxxxxxxxxx> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- kernel/trace/blktrace.c | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-) diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index ee7a8bb..95f89fa 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -426,11 +426,15 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, ret = -ENOENT; + mutex_lock(&blk_tree_mutex); if (!blk_tree_root) { blk_tree_root = debugfs_create_dir("block", NULL); - if (!blk_tree_root) + if (!blk_tree_root) { + mutex_unlock(&blk_tree_mutex); goto err; + } } + mutex_unlock(&blk_tree_mutex); dir = debugfs_create_dir(buts->name, blk_tree_root); -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html