diff options
| author | Trond Myklebust <trondmy@gmail.com> | 2020-01-06 13:20:47 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-01 13:17:28 +0200 |
| commit | fed639f7e1d5e562f58a1d2de87490e43831e519 (patch) | |
| tree | 0aa4b432b7747c0e1a99c418c332e72fd7d1977e /fs | |
| parent | 4f726a2afb99f1ba2d8af4251c0b44562511cf7a (diff) | |
nfsd: Fix a soft lockup race in nfsd_file_mark_find_or_create()
[ Upstream commit 90d2f1da832fd23290ef0c0d964d97501e5e8553 ]
If nfsd_file_mark_find_or_create() keeps winning the race for the
nfsd_file_fsnotify_group->mark_mutex against nfsd_file_mark_put()
then it can soft lock up, since fsnotify_add_inode_mark() ends
up always finding an existing entry.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfsd/filecache.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index 3007b8945d38..51c08ae79063 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -133,9 +133,13 @@ nfsd_file_mark_find_or_create(struct nfsd_file *nf) struct nfsd_file_mark, nfm_mark)); mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex); - fsnotify_put_mark(mark); - if (likely(nfm)) + if (nfm) { + fsnotify_put_mark(mark); break; + } + /* Avoid soft lockup race with nfsd_file_mark_put() */ + fsnotify_destroy_mark(mark, nfsd_file_fsnotify_group); + fsnotify_put_mark(mark); } else mutex_unlock(&nfsd_file_fsnotify_group->mark_mutex); |