====================================================== overlayfs: './bus' not a directory WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/17929 is trying to acquire lock: 0000000097020235 (&pipe->mutex/1){+.+.}, at: pipe_lock_nested fs/pipe.c:77 [inline] 0000000097020235 (&pipe->mutex/1){+.+.}, at: pipe_lock+0x63/0x80 fs/pipe.c:85 overlayfs: './bus' not a directory but task is already holding lock: 0000000008197468 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline] 0000000008197468 (sb_writers#3){.+.+}, at: do_splice fs/splice.c:1153 [inline] 0000000008197468 (sb_writers#3){.+.+}, at: __do_sys_splice fs/splice.c:1428 [inline] 0000000008197468 (sb_writers#3){.+.+}, at: __se_sys_splice+0x11de/0x16d0 fs/splice.c:1408 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (sb_writers#3){.+.+}: file_start_write include/linux/fs.h:2779 [inline] ovl_write_iter+0x932/0xb40 fs/overlayfs/file.c:282 call_write_iter include/linux/fs.h:1821 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x51b/0x770 fs/read_write.c:487 vfs_write+0x1f3/0x540 fs/read_write.c:549 ksys_write+0x12b/0x2a0 fs/read_write.c:599 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&ovl_i_mutex_key[depth]){+.+.}: overlayfs: './bus' not a directory inode_lock include/linux/fs.h:748 [inline] ovl_write_iter+0x148/0xb40 fs/overlayfs/file.c:270 call_write_iter include/linux/fs.h:1821 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x51b/0x770 fs/read_write.c:487 __kernel_write+0x109/0x370 fs/read_write.c:506 write_pipe_buf+0x153/0x1f0 fs/splice.c:798 splice_from_pipe_feed fs/splice.c:503 [inline] __splice_from_pipe+0x389/0x800 fs/splice.c:627 splice_from_pipe fs/splice.c:662 [inline] default_file_splice_write+0xd8/0x180 fs/splice.c:810 do_splice_from fs/splice.c:852 [inline] do_splice fs/splice.c:1154 [inline] __do_sys_splice fs/splice.c:1428 [inline] __se_sys_splice+0xfe7/0x16d0 fs/splice.c:1408 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&pipe->mutex/1){+.+.}: __mutex_lock_common kernel/locking/mutex.c:937 [inline] __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078 pipe_lock_nested fs/pipe.c:77 [inline] pipe_lock+0x63/0x80 fs/pipe.c:85 iter_file_splice_write+0x183/0xbb0 fs/splice.c:700 do_splice_from fs/splice.c:852 [inline] do_splice fs/splice.c:1154 [inline] __do_sys_splice fs/splice.c:1428 [inline] __se_sys_splice+0xfe7/0x16d0 fs/splice.c:1408 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: &pipe->mutex/1 --> &ovl_i_mutex_key[depth] --> sb_writers#3 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_writers#3); lock(&ovl_i_mutex_key[depth]); lock(sb_writers#3); lock(&pipe->mutex/1); *** DEADLOCK *** 1 lock held by syz-executor.4/17929: #0: 0000000008197468 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2779 [inline] #0: 0000000008197468 (sb_writers#3){.+.+}, at: do_splice fs/splice.c:1153 [inline] #0: 0000000008197468 (sb_writers#3){.+.+}, at: __do_sys_splice fs/splice.c:1428 [inline] #0: 0000000008197468 (sb_writers#3){.+.+}, at: __se_sys_splice+0x11de/0x16d0 fs/splice.c:1408 stack backtrace: CPU: 0 PID: 17929 Comm: syz-executor.4 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2420 [inline] __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 __mutex_lock_common kernel/locking/mutex.c:937 [inline] __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078 pipe_lock_nested fs/pipe.c:77 [inline] pipe_lock+0x63/0x80 fs/pipe.c:85 iter_file_splice_write+0x183/0xbb0 fs/splice.c:700 do_splice_from fs/splice.c:852 [inline] do_splice fs/splice.c:1154 [inline] __do_sys_splice fs/splice.c:1428 [inline] __se_sys_splice+0xfe7/0x16d0 fs/splice.c:1408 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f21e63070c9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f21e4879168 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 RAX: ffffffffffffffda RBX: 00007f21e6426f80 RCX: 00007f21e63070c9 RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 00007f21e6362ae9 R08: 000000000000fdef R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd63583f2f R14: 00007f21e4879300 R15: 0000000000022000 nla_parse: 5144 callbacks suppressed netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 32 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 32 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 32 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 32 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 32 bytes leftover after parsing attributes in process `syz-executor.3'. wlan1: No active IBSS STAs - trying to scan for other IBSS networks with same SSID (merge) x_tables: duplicate underflow at hook 1 kvm: emulating exchange as write nla_parse: 15861 callbacks suppressed netlink: 24 bytes leftover after parsing attributes in process `syz-executor.5'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 12 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 12 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 12 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 8 bytes leftover after parsing attributes in process `syz-executor.3'.