====================================================== WARNING: possible circular locking dependency detected 4.19.117-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/5459 is trying to acquire lock: 000000002605b8e9 (&sig->cred_guard_mutex){+.+.}, at: do_io_accounting+0x1da/0x7b0 fs/proc/base.c:2738 but task is already holding lock: 00000000da967655 (&p->lock){+.+.}, at: seq_read+0x6b/0x10f0 fs/seq_file.c:161 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: seq_read+0x6b/0x10f0 fs/seq_file.c:161 proc_reg_read+0x1bd/0x280 fs/proc/inode.c:231 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x46b/0x640 fs/read_write.c:925 vfs_readv+0xf0/0x160 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x478/0x970 fs/splice.c:417 do_splice_to+0x10e/0x160 fs/splice.c:881 splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959 do_splice_direct+0x1a8/0x270 fs/splice.c:1068 do_sendfile+0x549/0xc10 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64 fs/read_write.c:1494 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1494 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (sb_writers#3){.+.+}: sb_start_write include/linux/fs.h:1579 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:360 ovl_do_remove+0xf8/0xd70 fs/overlayfs/dir.c:843 vfs_rmdir fs/namei.c:3882 [inline] vfs_rmdir+0x194/0x460 fs/namei.c:3861 do_rmdir+0x371/0x3e0 fs/namei.c:3943 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&ovl_i_mutex_dir_key[depth]#2){++++}: inode_lock_shared include/linux/fs.h:758 [inline] do_last fs/namei.c:3326 [inline] path_openat+0x1d18/0x4200 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_open_execat+0x124/0x5b0 fs/exec.c:853 __do_execve_file.isra.0+0x1577/0x2110 fs/exec.c:1755 do_execveat_common fs/exec.c:1866 [inline] do_execve fs/exec.c:1883 [inline] __do_sys_execve fs/exec.c:1964 [inline] __se_sys_execve fs/exec.c:1959 [inline] __x64_sys_execve+0x8a/0xb0 fs/exec.c:1959 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sig->cred_guard_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1300 kernel/locking/mutex.c:1072 do_io_accounting+0x1da/0x7b0 fs/proc/base.c:2738 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4b9/0x10f0 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x46b/0x640 fs/read_write.c:925 vfs_readv+0xf0/0x160 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x478/0x970 fs/splice.c:417 do_splice_to+0x10e/0x160 fs/splice.c:881 splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959 do_splice_direct+0x1a8/0x270 fs/splice.c:1068 do_sendfile+0x549/0xc10 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64 fs/read_write.c:1494 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1494 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: &sig->cred_guard_mutex --> sb_writers#3 --> &p->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(sb_writers#3); lock(&p->lock); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 1 lock held by syz-executor.5/5459: #0: 00000000da967655 (&p->lock){+.+.}, at: seq_read+0x6b/0x10f0 fs/seq_file.c:161 stack backtrace: CPU: 0 PID: 5459 Comm: syz-executor.5 Not tainted 4.19.117-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x188/0x20d lib/dump_stack.c:118 print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1221 check_prev_add kernel/locking/lockdep.c:1865 [inline] check_prevs_add kernel/locking/lockdep.c:1978 [inline] validate_chain kernel/locking/lockdep.c:2419 [inline] __lock_acquire+0x2e19/0x49c0 kernel/locking/lockdep.c:3415 lock_acquire+0x170/0x400 kernel/locking/lockdep.c:3907 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1300 kernel/locking/mutex.c:1072 do_io_accounting+0x1da/0x7b0 fs/proc/base.c:2738 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4b9/0x10f0 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x46b/0x640 fs/read_write.c:925 vfs_readv+0xf0/0x160 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x478/0x970 fs/splice.c:417 do_splice_to+0x10e/0x160 fs/splice.c:881 splice_direct_to_actor+0x2b9/0x8d0 fs/splice.c:959 do_splice_direct+0x1a8/0x270 fs/splice.c:1068 do_sendfile+0x549/0xc10 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64 fs/read_write.c:1494 [inline] __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1494 IPVS: ftp: loaded support on port[0] = 21 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c829 Code: 0d b7 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 b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fa10c041c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00000000004fc040 RCX: 000000000045c829 RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000006 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0800000080004103 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000008d6 R14: 00000000004cb7a1 R15: 00007fa10c0426d4 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 IPVS: ftp: loaded support on port[0] = 21 xt_limit: Overflow, try lower: 3892314126/0 xt_limit: Overflow, try lower: 3892314126/0 xt_limit: Overflow, try lower: 3892314126/0 xt_limit: Overflow, try lower: 3892314126/0 xt_limit: Overflow, try lower: 3892314126/0 hid-generic 0000:0000:0000.0021: ignoring exceeding usage max hid-generic 0000:0000:0000.0021: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.0022: ignoring exceeding usage max hid-generic 0000:0000:0000.0022: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.0023: ignoring exceeding usage max hid-generic 0000:0000:0000.0024: ignoring exceeding usage max hid-generic 0000:0000:0000.0023: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.0024: hidraw1: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.0025: ignoring exceeding usage max hid-generic 0000:0000:0000.0026: ignoring exceeding usage max hid-generic 0000:0000:0000.0025: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.0027: ignoring exceeding usage max hid-generic 0000:0000:0000.0026: hidraw1: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.0028: ignoring exceeding usage max hid-generic 0000:0000:0000.0027: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.0029: ignoring exceeding usage max hid-generic 0000:0000:0000.0028: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.0029: hidraw1: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.002A: ignoring exceeding usage max hid-generic 0000:0000:0000.002B: ignoring exceeding usage max hid-generic 0000:0000:0000.002B: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.002A: hidraw1: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.002C: ignoring exceeding usage max hid-generic 0000:0000:0000.002D: ignoring exceeding usage max hid-generic 0000:0000:0000.002C: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.002D: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.002E: ignoring exceeding usage max hid-generic 0000:0000:0000.002E: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.002F: ignoring exceeding usage max hid-generic 0000:0000:0000.002F: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.0030: ignoring exceeding usage max hid-generic 0000:0000:0000.0030: hidraw0: HID v0.00 Device [syz1] on %z5 hid-generic 0000:0000:0000.0031: ignoring exceeding usage max hid-generic 0000:0000:0000.0031: hidraw0: HID v0.00 Device [syz1] on %z5 kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 6410 Comm: syz-executor.3 Not tainted 4.19.117-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:do_con_write.part.0+0x9c3/0x1db0 drivers/tty/vt/vt.c:2760 Code: 24 b6 00 00 00 45 01 ef e8 8a c9 c7 fd 48 8b 44 24 78 80 38 00 0f 85 4c 12 00 00 49 8b 9c 24 a0 03 00 00 48 89 d8 48 c1 e8 03 <0f> b6 14 28 48 89 d8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 c8 RSP: 0018:ffff88805d8bf930 EFLAGS: 00010203 RAX: 0000000020000001 RBX: 000000010000000e RCX: ffffc9000d0f3000 RDX: 00000000000003c3 RSI: ffffffff839fe016 RDI: 0000000000000003 RBP: dffffc0000000000 R08: ffff888049cb0440 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808cfa7700 R13: 0000000000000000 R14: ffff88808cfa7a8c R15: 000000000000703f FS: 00007f645eff0700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020001340 CR3: 000000002f32c000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: do_con_write drivers/tty/vt/vt.c:2565 [inline] con_write+0x41/0xe0 drivers/tty/vt/vt.c:3132 process_output_block drivers/tty/n_tty.c:593 [inline] n_tty_write+0x3ee/0x1080 drivers/tty/n_tty.c:2331 do_tty_write drivers/tty/tty_io.c:960 [inline] tty_write+0x452/0x790 drivers/tty/tty_io.c:1044 __vfs_write+0xf7/0x760 fs/read_write.c:485 vfs_write+0x206/0x550 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 RIP: 0033:0x45c829 Code: 0d b7 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 b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f645efefc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000509e40 RCX: 000000000045c829 RDX: 0000000000000246 RSI: 0000000020001340 RDI: 0000000000000004 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000c4e R14: 00000000004ca088 R15: 00007f645eff06d4 Modules linked in: ---[ end trace d8fe7cff9ee2269e ]--- RIP: 0010:do_con_write.part.0+0x9c3/0x1db0 drivers/tty/vt/vt.c:2760 Code: 24 b6 00 00 00 45 01 ef e8 8a c9 c7 fd 48 8b 44 24 78 80 38 00 0f 85 4c 12 00 00 49 8b 9c 24 a0 03 00 00 48 89 d8 48 c1 e8 03 <0f> b6 14 28 48 89 d8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 c8 RSP: 0018:ffff88805d8bf930 EFLAGS: 00010203 RAX: 0000000020000001 RBX: 000000010000000e RCX: ffffc9000d0f3000 RDX: 00000000000003c3 RSI: ffffffff839fe016 RDI: 0000000000000003 RBP: dffffc0000000000 R08: ffff888049cb0440 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88808cfa7700 R13: 0000000000000000 R14: ffff88808cfa7a8c R15: 000000000000703f FS: 00007f645eff0700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004d6940 CR3: 000000002f32c000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400