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authorAmir Goldstein <amir73il@gmail.com>2018-10-18 09:45:49 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2018-10-27 00:34:39 +0300
commit6cd078702f2f33cb6b19a682de3e9184112f1a46 (patch)
treecd6768dd4eb7a3ef952270de62aa3e4bfe23e4d6 /fs/overlayfs
parent8f97d1e99149a7f1aa19e47a51b09764382a482e (diff)
downloadlinux-6cd078702f2f33cb6b19a682de3e9184112f1a46.tar.xz
ovl: fix recursive oi->lock in ovl_link()
linking a non-copied-up file into a non-copied-up parent results in a nested call to mutex_lock_interruptible(&oi->lock). Fix this by copying up target parent before ovl_nlink_start(), same as done in ovl_rename(). ~/unionmount-testsuite$ ./run --ov -s ~/unionmount-testsuite$ ln /mnt/a/foo100 /mnt/a/dir100/ WARNING: possible recursive locking detected -------------------------------------------- ln/1545 is trying to acquire lock: 00000000bcce7c4c (&ovl_i_lock_key[depth]){+.+.}, at: ovl_copy_up_start+0x28/0x7d but task is already holding lock: 0000000026d73d5b (&ovl_i_lock_key[depth]){+.+.}, at: ovl_nlink_start+0x3c/0xc1 [SzM: this seems to be a false positive, but doing the copy-up first is harmless and removes the lockdep splat] Reported-by: syzbot+3ef5c0d1a5cb0b21e6be@syzkaller.appspotmail.com Fixes: 5f8415d6b87e ("ovl: persistent overlay inode nlink for...") Cc: <stable@vger.kernel.org> # v4.13 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/dir.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 276914ae3c60..e1a55ecb7aba 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -663,6 +663,10 @@ static int ovl_link(struct dentry *old, struct inode *newdir,
if (err)
goto out_drop_write;
+ err = ovl_copy_up(new->d_parent);
+ if (err)
+ goto out_drop_write;
+
if (ovl_is_metacopy_dentry(old)) {
err = ovl_set_redirect(old, false);
if (err)