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| author |   Trond Myklebust <trondmy@gmail.com> | 2020-01-06 13:20:47 -0500 |
|---|---|---|
| committer |   J. Bruce Fields <bfields@redhat.com> | 2020-01-22 16:25:40 -0500 |
| commit | 90d2f1da832fd23290ef0c0d964d97501e5e8553 (patch) | |
| tree | f268c330df953f234da0d75438c3802d20e0cc7b /fs/nfsd | |
| parent | nfsd: Reduce the number of calls to nfsd_file_gc() (diff) | |
| download | wireguard-linux-90d2f1da832fd23290ef0c0d964d97501e5e8553.tar.xz wireguard-linux-90d2f1da832fd23290ef0c0d964d97501e5e8553.zip | |
nfsd: Fix a soft lockup race in nfsd_file_mark_find_or_create()
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>
Diffstat (limited to 'fs/nfsd')
| -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 9c2b29e07975..f275c11c4e28 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -132,9 +132,13 @@ 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); |