====================================================== WARNING: possible circular locking dependency detected 6.10.0-syzkaller-11185-g2c9b3512402e #0 Not tainted ------------------------------------------------------ syz.0.2694/13477 is trying to acquire lock: ffff888000c6e088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325 but task is already holding lock: ffff888027c60868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:92 [inline] ffff888027c60868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock+0x64/0x80 fs/pipe.c:89 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&pipe->mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752 pipe_write+0x16c/0x1b50 fs/pipe.c:455 __kernel_write_iter+0x710/0xa80 fs/read_write.c:523 __kernel_write+0xf6/0x140 fs/read_write.c:543 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x48c/0xbf0 fs/autofs/waitq.c:164 autofs_wait+0x12ca/0x1c40 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x380 fs/autofs/root.c:255 autofs_d_automount+0x390/0x7f0 fs/autofs/root.c:401 follow_automount fs/namei.c:1394 [inline] __traverse_mounts+0x192/0x760 fs/namei.c:1439 traverse_mounts fs/namei.c:1468 [inline] handle_mounts fs/namei.c:1571 [inline] step_into+0x888/0x2230 fs/namei.c:1877 walk_component+0xfc/0x5b0 fs/namei.c:2045 lookup_last fs/namei.c:2542 [inline] path_lookupat+0x17f/0x770 fs/namei.c:2566 filename_lookup+0x1e5/0x5b0 fs/namei.c:2595 user_path_at+0x3a/0x60 fs/namei.c:3002 path_listxattr+0x99/0x160 fs/xattr.c:861 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #1 (&sbi->pipe_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x45a/0xbf0 fs/autofs/waitq.c:164 autofs_wait+0x12ca/0x1c40 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x380 fs/autofs/root.c:255 autofs_d_automount+0x390/0x7f0 fs/autofs/root.c:401 follow_automount fs/namei.c:1394 [inline] __traverse_mounts+0x192/0x760 fs/namei.c:1439 traverse_mounts fs/namei.c:1468 [inline] handle_mounts fs/namei.c:1571 [inline] step_into+0x888/0x2230 fs/namei.c:1877 walk_component+0xfc/0x5b0 fs/namei.c:2045 lookup_last fs/namei.c:2542 [inline] path_lookupat+0x17f/0x770 fs/namei.c:2566 filename_lookup+0x1e5/0x5b0 fs/namei.c:2595 kern_path+0x35/0x50 fs/namei.c:2703 lookup_bdev+0xd9/0x280 block/bdev.c:1157 resume_store+0x1d8/0x460 kernel/power/hibernate.c:1235 kobj_attr_store+0x55/0x80 lib/kobject.c:840 sysfs_kf_write+0x117/0x170 fs/sysfs/file.c:136 kernfs_fop_write_iter+0x343/0x500 fs/kernfs/file.c:334 iter_file_splice_write+0x906/0x10b0 fs/splice.c:743 do_splice_from fs/splice.c:941 [inline] direct_splice_actor+0x19b/0x6d0 fs/splice.c:1164 splice_direct_to_actor+0x346/0xa40 fs/splice.c:1108 do_splice_direct_actor fs/splice.c:1207 [inline] do_splice_direct+0x17e/0x250 fs/splice.c:1233 do_sendfile+0xb1e/0xe50 fs/read_write.c:1295 __do_compat_sys_sendfile fs/read_write.c:1383 [inline] __se_compat_sys_sendfile fs/read_write.c:1366 [inline] __ia32_compat_sys_sendfile+0x1e7/0x230 fs/read_write.c:1366 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #0 (&of->mutex){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3133 [inline] check_prevs_add kernel/locking/lockdep.c:3252 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142 lock_acquire kernel/locking/lockdep.c:5759 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752 kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325 iter_file_splice_write+0x906/0x10b0 fs/splice.c:743 do_splice_from fs/splice.c:941 [inline] do_splice+0x148c/0x1f90 fs/splice.c:1354 __do_splice+0x327/0x360 fs/splice.c:1436 __do_sys_splice fs/splice.c:1652 [inline] __se_sys_splice fs/splice.c:1634 [inline] __ia32_sys_splice+0x1d0/0x260 fs/splice.c:1634 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e other info that might help us debug this: Chain exists of: &of->mutex --> &sbi->pipe_mutex --> &pipe->mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&pipe->mutex); lock(&sbi->pipe_mutex); lock(&pipe->mutex); lock(&of->mutex); *** DEADLOCK *** 2 locks held by syz.0.2694/13477: #0: ffff8880268d6420 (sb_writers#8){.+.+}-{0:0}, at: __do_splice+0x327/0x360 fs/splice.c:1436 #1: ffff888027c60868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock fs/pipe.c:92 [inline] #1: ffff888027c60868 (&pipe->mutex){+.+.}-{3:3}, at: pipe_lock+0x64/0x80 fs/pipe.c:89 stack backtrace: CPU: 3 PID: 13477 Comm: syz.0.2694 Not tainted 6.10.0-syzkaller-11185-g2c9b3512402e #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2186 check_prev_add kernel/locking/lockdep.c:3133 [inline] check_prevs_add kernel/locking/lockdep.c:3252 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142 lock_acquire kernel/locking/lockdep.c:5759 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x175/0x9c0 kernel/locking/mutex.c:752 kernfs_fop_write_iter+0x281/0x500 fs/kernfs/file.c:325 iter_file_splice_write+0x906/0x10b0 fs/splice.c:743 do_splice_from fs/splice.c:941 [inline] do_splice+0x148c/0x1f90 fs/splice.c:1354 __do_splice+0x327/0x360 fs/splice.c:1436 __do_sys_splice fs/splice.c:1652 [inline] __se_sys_splice fs/splice.c:1634 [inline] __ia32_sys_splice+0x1d0/0x260 fs/splice.c:1634 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline] __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf7f62579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f5cf556c EFLAGS: 00000296 ORIG_RAX: 0000000000000139 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000000000 RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000002 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 PM: Enabling pm_trace changes system date and time during resume. PM: Correct system time has to be restored manually after resume. ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi