| Message ID | 20200106182047.563178-1-trond.myklebust@hammerspace.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | nfsd: Fix a soft lockup race in nfsd_file_mark_find_or_create() | expand |
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);
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> --- fs/nfsd/filecache.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)