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| author | Li Zefan <lizf@cn.fujitsu.com> | 2009-03-25 17:19:33 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-03-31 17:26:59 +0200 |
| commit | b5230b56ee6caeb27cedb7753c0c319646383bb4 (patch) | |
| tree | a8cb9730ba9d89346d3bd959393e72c84b36ce84 /kernel | |
| parent | 6c051ce0307526adec32a847f0daa1af2124f0a9 (diff) | |
| download | linux-b5230b56ee6caeb27cedb7753c0c319646383bb4.tar.gz linux-b5230b56ee6caeb27cedb7753c0c319646383bb4.tar.bz2 linux-b5230b56ee6caeb27cedb7753c0c319646383bb4.zip | |
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@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | 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 ee7a8bb8b1e8..95f89faca73e 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); |