====================================================== WARNING: possible circular locking dependency detected 5.0.0-rc5 #60 Not tainted ------------------------------------------------------ syz-executor5/25206 is trying to acquire lock: 000000005e1828ab (&sig->cred_guard_mutex){+.+.}, at: lock_trace+0x4a/0xe0 fs/proc/base.c:384 but task is already holding lock: 0000000041d5800c (&p->lock){+.+.}, at: seq_read+0x71/0x1130 fs/seq_file.c:161 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 seq_read+0x71/0x1130 fs/seq_file.c:161 do_loop_readv_writev fs/read_write.c:700 [inline] do_loop_readv_writev fs/read_write.c:687 [inline] do_iter_read+0x4a9/0x660 fs/read_write.c:921 vfs_readv+0xf0/0x160 fs/read_write.c:983 kernel_readv fs/splice.c:362 [inline] default_file_splice_read+0x475/0x890 fs/splice.c:417 do_splice_to+0x12a/0x190 fs/splice.c:880 splice_direct_to_actor+0x2d2/0x970 fs/splice.c:957 do_splice_direct+0x1da/0x2a0 fs/splice.c:1066 do_sendfile+0x597/0xd00 fs/read_write.c:1436 __do_sys_sendfile64 fs/read_write.c:1497 [inline] __se_sys_sendfile64 fs/read_write.c:1483 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1483 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (sb_writers#3){.+.+}: percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline] percpu_down_read include/linux/percpu-rwsem.h:59 [inline] __sb_start_write+0x20b/0x360 fs/super.c:1389 sb_start_write include/linux/fs.h:1603 [inline] mnt_want_write+0x3f/0xc0 fs/namespace.c:357 ovl_want_write+0x76/0xa0 fs/overlayfs/util.c:24 ovl_create_object+0xb3/0x2c0 fs/overlayfs/dir.c:599 ovl_create+0x28/0x30 fs/overlayfs/dir.c:630 lookup_open+0x12e0/0x1b10 fs/namei.c:3234 do_last fs/namei.c:3324 [inline] path_openat+0x149a/0x4690 fs/namei.c:3534 do_filp_open+0x1a1/0x280 fs/namei.c:3564 do_sys_open+0x3fe/0x5d0 fs/open.c:1063 __do_sys_open fs/open.c:1081 [inline] __se_sys_open fs/open.c:1076 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1076 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&ovl_i_mutex_dir_key[depth]){++++}: down_read+0x3b/0x90 kernel/locking/rwsem.c:24 inode_lock_shared include/linux/fs.h:767 [inline] do_last fs/namei.c:3323 [inline] path_openat+0x1e79/0x4690 fs/namei.c:3534 do_filp_open+0x1a1/0x280 fs/namei.c:3564 do_open_execat+0x13b/0x6d0 fs/exec.c:856 __do_execve_file.isra.0+0x178d/0x23f0 fs/exec.c:1758 do_execveat_common fs/exec.c:1865 [inline] do_execve fs/exec.c:1882 [inline] __do_sys_execve fs/exec.c:1963 [inline] __se_sys_execve fs/exec.c:1958 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1958 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&sig->cred_guard_mutex){+.+.}: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3841 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1310 kernel/locking/mutex.c:1072 mutex_lock_killable_nested+0x16/0x20 kernel/locking/mutex.c:1102 lock_trace+0x4a/0xe0 fs/proc/base.c:384 proc_pid_stack+0x13e/0x2c0 fs/proc/base.c:434 proc_single_show+0xf6/0x180 fs/proc/base.c:739 seq_read+0x4db/0x1130 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:700 [inline] do_loop_readv_writev fs/read_write.c:687 [inline] do_iter_read+0x4a9/0x660 fs/read_write.c:921 vfs_readv+0xf0/0x160 fs/read_write.c:983 do_preadv+0x1c4/0x280 fs/read_write.c:1067 __do_sys_preadv fs/read_write.c:1117 [inline] __se_sys_preadv fs/read_write.c:1112 [inline] __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1112 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 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-executor5/25206: #0: 0000000041d5800c (&p->lock){+.+.}, at: seq_read+0x71/0x1130 fs/seq_file.c:161 stack backtrace: CPU: 0 PID: 25206 Comm: syz-executor5 Not tainted 5.0.0-rc5 #60 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+0x172/0x1f0 lib/dump_stack.c:113 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1224 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2350 [inline] __lock_acquire+0x2f00/0x4700 kernel/locking/lockdep.c:3338 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3841 __mutex_lock_common kernel/locking/mutex.c:925 [inline] __mutex_lock+0xf7/0x1310 kernel/locking/mutex.c:1072 mutex_lock_killable_nested+0x16/0x20 kernel/locking/mutex.c:1102 lock_trace+0x4a/0xe0 fs/proc/base.c:384 proc_pid_stack+0x13e/0x2c0 fs/proc/base.c:434 proc_single_show+0xf6/0x180 fs/proc/base.c:739 seq_read+0x4db/0x1130 fs/seq_file.c:229 do_loop_readv_writev fs/read_write.c:700 [inline] do_loop_readv_writev fs/read_write.c:687 [inline] do_iter_read+0x4a9/0x660 fs/read_write.c:921 vfs_readv+0xf0/0x160 fs/read_write.c:983 do_preadv+0x1c4/0x280 fs/read_write.c:1067 __do_sys_preadv fs/read_write.c:1117 [inline] __se_sys_preadv fs/read_write.c:1112 [inline] __x64_sys_preadv+0x9a/0xf0 fs/read_write.c:1112 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457e39 Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f1d693a3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457e39 RDX: 100000000000013f RSI: 0000000020000480 RDI: 0000000000000004 RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1d693a46d4 R13: 00000000004c48e1 R14: 00000000004d8060 R15: 00000000ffffffff kobject: 'kvm' (000000005f0fff20): kobject_uevent_env bridge: RTM_NEWNEIGH with invalid state 0x0 kobject: 'kvm' (000000005f0fff20): fill_kobj_path: path = '/devices/virtual/misc/kvm' IPVS: ftp: loaded support on port[0] = 21 kobject: 'loop1' (000000002f53263e): kobject_uevent_env kobject: 'loop1' (000000002f53263e): fill_kobj_path: path = '/devices/virtual/block/loop1' bridge: RTM_NEWNEIGH with invalid state 0x0 kobject: 'kvm' (000000005f0fff20): kobject_uevent_env kobject: 'kvm' (000000005f0fff20): fill_kobj_path: path = '/devices/virtual/misc/kvm' kobject: 'loop4' (00000000da2710c5): kobject_uevent_env kobject: 'loop4' (00000000da2710c5): fill_kobj_path: path = '/devices/virtual/block/loop4' bridge: RTM_NEWNEIGH with invalid state 0x0 kobject: 'loop2' (00000000812dc4c9): kobject_uevent_env kobject: 'kvm' (000000005f0fff20): kobject_uevent_env kobject: 'loop2' (00000000812dc4c9): fill_kobj_path: path = '/devices/virtual/block/loop2' kobject: 'lo' (00000000eb3c93dc): kobject_add_internal: parent: 'net', set: 'devices' kobject: 'kvm' (000000005f0fff20): fill_kobj_path: path = '/devices/virtual/misc/kvm' kobject: 'loop1' (000000002f53263e): kobject_uevent_env kobject: 'kvm' (000000005f0fff20): kobject_uevent_env kobject: 'loop1' (000000002f53263e): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'kvm' (000000005f0fff20): kobject_uevent_env kobject: 'lo' (00000000eb3c93dc): kobject_uevent_env kobject: 'kvm' (000000005f0fff20): fill_kobj_path: path = '/devices/virtual/misc/kvm' kobject: 'kvm' (000000005f0fff20): fill_kobj_path: path = '/devices/virtual/misc/kvm' kobject: 'lo' (00000000eb3c93dc): fill_kobj_path: path = '/devices/virtual/net/lo' kobject: 'queues' (000000005f9e1b3a): kobject_add_internal: parent: 'lo', set: '' kobject: 'kvm' (000000005f0fff20): kobject_uevent_env kobject: 'kvm' (000000005f0fff20): fill_kobj_path: path = '/devices/virtual/misc/kvm' kobject: 'queues' (000000005f9e1b3a): kobject_uevent_env kobject: 'loop2' (00000000812dc4c9): kobject_uevent_env kobject: 'queues' (000000005f9e1b3a): kobject_uevent_env: filter function caused the event to drop! kobject: 'rx-0' (000000005feafe25): kobject_add_internal: parent: 'queues', set: 'queues' kobject: 'loop2' (00000000812dc4c9): fill_kobj_path: path = '/devices/virtual/block/loop2' kobject: 'rx-0' (000000005feafe25): kobject_uevent_env kobject: 'rx-0' (000000005feafe25): fill_kobj_path: path = '/devices/virtual/net/lo/queues/rx-0' kobject: 'tx-0' (0000000029852fcb): kobject_add_internal: parent: 'queues', set: 'queues' IPVS: ftp: loaded support on port[0] = 21 kobject: 'tx-0' (0000000029852fcb): kobject_uevent_env kobject: 'tx-0' (0000000029852fcb): fill_kobj_path: path = '/devices/virtual/net/lo/queues/tx-0' kobject: 'loop5' (00000000ca896c57): kobject_uevent_env kobject: 'tunl0' (000000005b277a62): kobject_add_internal: parent: 'net', set: 'devices' kobject: 'loop5' (00000000ca896c57): fill_kobj_path: path = '/devices/virtual/block/loop5' kobject: 'tunl0' (000000005b277a62): kobject_uevent_env kobject: 'tunl0' (000000005b277a62): fill_kobj_path: path = '/devices/virtual/net/tunl0' kobject: 'loop4' (00000000da2710c5): kobject_uevent_env kobject: 'queues' (0000000087ceaccf): kobject_add_internal: parent: 'tunl0', set: '' kobject: 'loop4' (00000000da2710c5): fill_kobj_path: path = '/devices/virtual/block/loop4' kobject: 'queues' (0000000087ceaccf): kobject_uevent_env kobject: 'queues' (0000000087ceaccf): kobject_uevent_env: filter function caused the event to drop! kobject: 'rx-0' (00000000d9c8a47e): kobject_add_internal: parent: 'queues', set: 'queues' kobject: 'rx-0' (00000000d9c8a47e): kobject_uevent_env kobject: 'rx-0' (00000000d9c8a47e): fill_kobj_path: path = '/devices/virtual/net/tunl0/queues/rx-0' kobject: 'tx-0' (0000000083795f9a): kobject_add_internal: parent: 'queues', set: 'queues' kobject: 'tx-0' (0000000083795f9a): kobject_uevent_env kobject: 'tx-0' (0000000083795f9a): fill_kobj_path: path = '/devices/virtual/net/tunl0/queues/tx-0' kobject: 'gre0' (00000000b341167e): kobject_add_internal: parent: 'net', set: 'devices' kobject: 'gre0' (00000000b341167e): kobject_uevent_env kobject: 'gre0' (00000000b341167e): fill_kobj_path: path = '/devices/virtual/net/gre0' kobject: 'queues' (00000000976e6ac6): kobject_add_internal: parent: 'gre0', set: '' kobject: 'queues' (00000000976e6ac6): kobject_uevent_env kobject: 'queues' (00000000976e6ac6): kobject_uevent_env: filter function caused the event to drop! kobject: 'rx-0' (0000000007ca9078): kobject_add_internal: parent: 'queues', set: 'queues' kobject: 'rx-0' (0000000007ca9078): kobject_uevent_env kobject: 'rx-0' (0000000007ca9078): fill_kobj_path: path = '/devices/virtual/net/gre0/queues/rx-0' kobject: 'tx-0' (000000002fb8c71f): kobject_add_internal: parent: 'queues', set: 'queues' kobject: 'tx-0' (000000002fb8c71f): kobject_uevent_env kobject: 'tx-0' (000000002fb8c71f): fill_kobj_path: path = '/devices/virtual/net/gre0/queues/tx-0' kobject: 'gretap0' (0000000088647fb8): kobject_add_internal: parent: 'net', set: 'devices' kobject: 'gretap0' (0000000088647fb8): kobject_uevent_env kobject: 'gretap0' (0000000088647fb8): fill_kobj_path: path = '/devices/virtual/net/gretap0' kobject: 'queues' (00000000177e513d): kobject_add_internal: parent: 'gretap0', set: '' kobject: 'queues' (00000000177e513d): kobject_uevent_env kobject: 'queues' (00000000177e513d): kobject_uevent_env: filter function caused the event to drop! kobject: 'rx-0' (00000000b1b21e5b): kobject_add_internal: parent: 'queues', set: 'queues' kobject: 'rx-0' (00000000b1b21e5b): kobject_uevent_env kobject: 'rx-0' (00000000b1b21e5b): fill_kobj_path: path = '/devices/virtual/net/gretap0/queues/rx-0' kobject: 'tx-0' (000000005884a9fc): kobject_add_internal: parent: 'queues', set: 'queues' kobject: 'loop0' (000000001b28e259): kobject_uevent_env kobject: 'loop0' (000000001b28e259): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'tx-0' (000000005884a9fc): kobject_uevent_env kobject: 'tx-0' (000000005884a9fc): fill_kobj_path: path = '/devices/virtual/net/gretap0/queues/tx-0' kobject: 'kvm' (000000005f0fff20): kobject_uevent_env kobject: 'batman_adv' (00000000dff1c0ac): kobject_add_internal: parent: 'gretap0', set: '' kobject: 'kvm' (000000005f0fff20): fill_kobj_path: path = '/devices/virtual/misc/kvm' bridge: RTM_NEWNEIGH with invalid state 0x0 kobject: 'erspan0' (00000000e16bc80b): kobject_add_internal: parent: 'net', set: 'devices' kobject: 'loop0' (000000001b28e259): kobject_uevent_env kobject: 'kvm' (000000005f0fff20): kobject_uevent_env kobject: 'loop0' (000000001b28e259): fill_kobj_path: path = '/devices/virtual/block/loop0' kobject: 'erspan0' (00000000e16bc80b): kobject_uevent_env kobject: 'kvm' (000000005f0fff20): kobject_uevent_env kobject: 'loop1' (000000002f53263e): kobject_uevent_env kobject: 'kvm' (000000005f0fff20): fill_kobj_path: path = '/devices/virtual/misc/kvm' kobject: 'loop1' (000000002f53263e): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'erspan0' (00000000e16bc80b): fill_kobj_path: path = '/devices/virtual/net/erspan0' kobject: 'kvm' (000000005f0fff20): fill_kobj_path: path = '/devices/virtual/misc/kvm' kobject: 'kvm' (000000005f0fff20): kobject_uevent_env kobject: 'kvm' (000000005f0fff20): fill_kobj_path: path = '/devices/virtual/misc/kvm' kobject: 'queues' (00000000b7514e46): kobject_add_internal: parent: 'erspan0', set: '' kobject: 'queues' (00000000b7514e46): kobject_uevent_env kobject: 'queues' (00000000b7514e46): kobject_uevent_env: filte