The commit is pushed to "branch-rh7-3.10.0-862.20.2.vz7.73.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git after rh7-3.10.0-862.20.2.vz7.73.17 ------> commit 92f85553310b4c8d70f9388c1c837aabc3f1e9d6 Author: Amir Goldstein <amir7...@gmail.com> Date: Thu Oct 18 09:45:49 2018 +0300
ms/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+3ef5c0d1a5cb0b21e...@syzkaller.appspotmail.com Fixes: 5f8415d6b87e ("ovl: persistent overlay inode nlink for...") Cc: <sta...@vger.kernel.org> # v4.13 Signed-off-by: Amir Goldstein <amir7...@gmail.com> Signed-off-by: Miklos Szeredi <mszer...@redhat.com> https://pmc.acronis.com/browse/VSTOR-18481 (cherry picked from commit 6cd078702f2f33cb6b19a682de3e9184112f1a46) Signed-off-by: Konstantin Khorenko <khore...@virtuozzo.com> --- fs/overlayfs/dir.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 7fb210b2c5dc..8147151a6cac 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -638,6 +638,10 @@ 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; + err = ovl_nlink_start(old, &locked); if (err) goto out_drop_write; _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel