On Mon, Feb 1, 2021 at 11:21 AM syzbot <syzbot+6a023cb2262c79301432@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 6642d600 Merge tag '5.11-rc5-smb3' of git://git.samba.org/.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=148aef78d00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=9408d1770a50819c > dashboard link: https://syzkaller.appspot.com/bug?extid=6a023cb2262c79301432 > compiler: clang version 11.0.1 > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+6a023cb2262c79301432@xxxxxxxxxxxxxxxxxxxxxxxxx > > ============================================ > WARNING: possible recursive locking detected > 5.11.0-rc5-syzkaller #0 Not tainted > -------------------------------------------- > syz-executor.2/3639 is trying to acquire lock: > ffff888084c0b5f0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: inode_lock include/linux/fs.h:773 [inline] > ffff888084c0b5f0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: ovl_dir_real_file+0x20b/0x310 fs/overlayfs/readdir.c:886 > > but task is already holding lock: > ffff888084c0b5f0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: inode_lock include/linux/fs.h:773 [inline] > ffff888084c0b5f0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: ovl_ioctl_set_flags fs/overlayfs/file.c:530 [inline] > ffff888084c0b5f0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: ovl_ioctl+0x2fb/0x960 fs/overlayfs/file.c:569 > > other info that might help us debug this: > Possible unsafe locking scenario: > > CPU0 > ---- > lock(&ovl_i_mutex_dir_key[depth]); > lock(&ovl_i_mutex_dir_key[depth]); > > *** DEADLOCK *** > > May be due to missing lock nesting notation > > 2 locks held by syz-executor.2/3639: > #0: ffff88807a706460 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write_file+0x5a/0x250 fs/namespace.c:412 > #1: ffff888084c0b5f0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: inode_lock include/linux/fs.h:773 [inline] > #1: ffff888084c0b5f0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: ovl_ioctl_set_flags fs/overlayfs/file.c:530 [inline] > #1: ffff888084c0b5f0 (&ovl_i_mutex_dir_key[depth]){++++}-{3:3}, at: ovl_ioctl+0x2fb/0x960 fs/overlayfs/file.c:569 > > stack backtrace: > CPU: 1 PID: 3639 Comm: syz-executor.2 Not tainted 5.11.0-rc5-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0x137/0x1be lib/dump_stack.c:120 > __lock_acquire+0x2333/0x5e90 kernel/locking/lockdep.c:4670 > lock_acquire+0x114/0x5e0 kernel/locking/lockdep.c:5442 > down_write+0x56/0x120 kernel/locking/rwsem.c:1406 > inode_lock include/linux/fs.h:773 [inline] > ovl_dir_real_file+0x20b/0x310 fs/overlayfs/readdir.c:886 > ovl_real_fdget fs/overlayfs/file.c:136 [inline] > ovl_real_ioctl fs/overlayfs/file.c:499 [inline] > ovl_ioctl_set_flags fs/overlayfs/file.c:545 [inline] > ovl_ioctl+0x4de/0x960 fs/overlayfs/file.c:569 > vfs_ioctl fs/ioctl.c:48 [inline] > __do_sys_ioctl fs/ioctl.c:753 [inline] > __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:739 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x45e219 > Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f02ed677c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e219 > RDX: 0000000000000000 RSI: 0000000040086602 RDI: 0000000000000003 > RBP: 000000000119bfc0 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c > R13: 00007ffd373df6ef R14: 00007f02ed6789c0 R15: 000000000119bf8c > > #syz fix: ovl: avoid deadlock on directory ioctl Should be in linux-next tree already. Thanks, Amir.
