====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/22636 is trying to acquire lock: 00000000cf73322a (&sig->cred_guard_mutex){+.+.}, at: lock_trace fs/proc/base.c:402 [inline] 00000000cf73322a (&sig->cred_guard_mutex){+.+.}, at: proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635 but task is already holding lock: 00000000dec59aaa (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: seq_read+0x6b/0x11c0 fs/seq_file.c:164 proc_reg_read+0x1bd/0x2d0 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+0x471/0x630 fs/read_write.c:925 vfs_readv+0xe5/0x150 fs/read_write.c:987 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x457/0xa00 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+0x1a7/0x270 fs/splice.c:1068 do_sendfile+0x550/0xc30 fs/read_write.c:1447 __do_sys_sendfile64 fs/read_write.c:1508 [inline] __se_sys_sendfile64+0x147/0x160 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_create_object+0x96/0x290 fs/overlayfs/dir.c:602 lookup_open+0x893/0x1a20 fs/namei.c:3235 do_last fs/namei.c:3327 [inline] path_openat+0x1094/0x2df0 fs/namei.c:3537 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_sys_open+0x3b3/0x520 fs/open.c:1085 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]){++++}: inode_lock_shared include/linux/fs.h:758 [inline] lookup_slow fs/namei.c:1688 [inline] walk_component+0x798/0xda0 fs/namei.c:1811 link_path_walk.part.0+0x901/0x1230 fs/namei.c:2142 link_path_walk fs/namei.c:2073 [inline] path_openat+0x1db/0x2df0 fs/namei.c:3536 do_filp_open+0x18c/0x3f0 fs/namei.c:3567 do_open_execat+0x11d/0x5b0 fs/exec.c:853 __do_execve_file+0x1a8b/0x2360 fs/exec.c:1770 do_execveat_common fs/exec.c:1879 [inline] do_execve+0x35/0x50 fs/exec.c:1896 __do_sys_execve fs/exec.c:1977 [inline] __se_sys_execve fs/exec.c:1972 [inline] __x64_sys_execve+0x7c/0xa0 fs/exec.c:1972 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:937 [inline] __mutex_lock+0xd7/0x1190 kernel/locking/mutex.c:1078 lock_trace fs/proc/base.c:402 [inline] proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4e0/0x11c0 fs/seq_file.c:232 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x471/0x630 fs/read_write.c:925 vfs_readv+0xe5/0x150 fs/read_write.c:987 do_preadv fs/read_write.c:1071 [inline] __do_sys_preadv fs/read_write.c:1121 [inline] __se_sys_preadv fs/read_write.c:1116 [inline] __x64_sys_preadv+0x22b/0x310 fs/read_write.c:1116 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.5/22636: #0: 00000000dec59aaa (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 stack backtrace: CPU: 1 PID: 22636 Comm: syz-executor.5 Not tainted 4.19.211-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+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 lock_trace fs/proc/base.c:402 [inline] proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4e0/0x11c0 fs/seq_file.c:232 do_loop_readv_writev fs/read_write.c:701 [inline] do_loop_readv_writev fs/read_write.c:688 [inline] do_iter_read+0x471/0x630 fs/read_write.c:925 vfs_readv+0xe5/0x150 fs/read_write.c:987 do_preadv fs/read_write.c:1071 [inline] __do_sys_preadv fs/read_write.c:1121 [inline] __se_sys_preadv fs/read_write.c:1116 [inline] __x64_sys_preadv+0x22b/0x310 fs/read_write.c:1116 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7ff7584fb059 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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:00007ff756e4f168 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007ff75860e030 RCX: 00007ff7584fb059 RDX: 0000000000000333 RSI: 00000000200017c0 RDI: 0000000000000006 RBP: 00007ff75855508d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdd20c1f5f R14: 00007ff756e4f300 R15: 0000000000022000 audit: type=1804 audit(1644512639.771:441): pid=22625 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.5" name="/root/syzkaller-testdir691462305/syzkaller.3YY8Yn/427/file0" dev="sda1" ino=13941 res=1 audit: type=1804 audit(1644512640.651:442): pid=22674 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.3" name="/root/syzkaller-testdir735228260/syzkaller.DRiDhL/3192/file0" dev="sda1" ino=15188 res=1 audit: type=1804 audit(1644512641.531:443): pid=22715 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.3" name="/root/syzkaller-testdir735228260/syzkaller.DRiDhL/3193/file0" dev="sda1" ino=16777 res=1 audit: type=1804 audit(1644512641.681:444): pid=22760 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.0" name="/root/syzkaller-testdir771779888/syzkaller.vLNryr/3171/bus" dev="sda1" ino=16777 res=1 Bluetooth: hci3: command 0x0406 tx timeout audit: type=1800 audit(1644512641.681:445): pid=22760 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="bus" dev="sda1" ino=16777 res=0 audit: type=1804 audit(1644512642.471:446): pid=22789 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.0" name="/root/syzkaller-testdir771779888/syzkaller.vLNryr/3173/bus" dev="sda1" ino=16805 res=1 audit: type=1800 audit(1644512642.471:447): pid=22789 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.0" name="bus" dev="sda1" ino=16805 res=0 audit: type=1804 audit(1644512642.561:448): pid=22793 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.2" name="/root/syzkaller-testdir771633206/syzkaller.ScgrIf/2520/file1/bus" dev="loop2" ino=22 res=1 audit: type=1800 audit(1644512642.561:449): pid=22793 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.2" name="bus" dev="loop2" ino=22 res=0 audit: type=1804 audit(1644512643.281:450): pid=22791 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.3" name="/root/syzkaller-testdir735228260/syzkaller.DRiDhL/3195/file0" dev="sda1" ino=15188 res=1 kauditd_printk_skb: 5 callbacks suppressed audit: type=1804 audit(1644512645.221:456): pid=22921 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=ToMToU comm="syz-executor.1" name="/root/syzkaller-testdir399167449/syzkaller.4DgVfB/3239/file0" dev="sda1" ino=14705 res=1 TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0 hid-generic 0000:0000:0000.0001: unknown main item tag 0x0