diff options
| author | Jan Kara <jack@suse.cz> | 2021-04-06 19:17:59 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-11 15:47:37 +0300 |
| commit | 9aca313726cb657325eeb01ab00142a6572c2175 (patch) | |
| tree | f1cc2f0d7c115eb9c2d3e1f14ec12f52b26db639 /fs/jbd2 | |
| parent | a27aad32175179083e6a05b7c58d047639a1b1c0 (diff) | |
| download | linux-9aca313726cb657325eeb01ab00142a6572c2175.tar.xz | |
ext4: annotate data race in start_this_handle()
commit 3b1833e92baba135923af4a07e73fe6e54be5a2f upstream.
Access to journal->j_running_transaction is not protected by appropriate
lock and thus is racy. We are well aware of that and the code handles
the race properly. Just add a comment and data_race() annotation.
Cc: stable@kernel.org
Reported-by: syzbot+30774a6acf6a2cf6d535@syzkaller.appspotmail.com
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210406161804.20150-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/jbd2')
| -rw-r--r-- | fs/jbd2/transaction.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index 9396666b7314..398d1d9209e2 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -349,7 +349,12 @@ static int start_this_handle(journal_t *journal, handle_t *handle, } alloc_transaction: - if (!journal->j_running_transaction) { + /* + * This check is racy but it is just an optimization of allocating new + * transaction early if there are high chances we'll need it. If we + * guess wrong, we'll retry or free unused transaction. + */ + if (!data_race(journal->j_running_transaction)) { /* * If __GFP_FS is not present, then we may be being called from * inside the fs writeback layer, so we MUST NOT fail. |