====================================================== WARNING: possible circular locking dependency detected 4.14.218-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/24270 is trying to acquire lock: (&ovl_i_mutex_dir_key[depth]){++++}, at: [] inode_lock_shared include/linux/fs.h:729 [inline] (&ovl_i_mutex_dir_key[depth]){++++}, at: [] do_last fs/namei.c:3333 [inline] (&ovl_i_mutex_dir_key[depth]){++++}, at: [] path_openat+0x149b/0x2970 fs/namei.c:3569 but task is already holding lock: (&sig->cred_guard_mutex){+.+.}, at: [] prepare_bprm_creds fs/exec.c:1404 [inline] (&sig->cred_guard_mutex){+.+.}, at: [] do_execveat_common+0x319/0x1f30 fs/exec.c:1748 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&sig->cred_guard_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 lock_trace fs/proc/base.c:407 [inline] proc_pid_personality+0x48/0x160 fs/proc/base.c:2913 proc_single_show+0xe7/0x150 fs/proc/base.c:761 seq_read+0x4cf/0x1120 fs/seq_file.c:237 __vfs_read+0xe4/0x620 fs/read_write.c:411 vfs_read+0x139/0x340 fs/read_write.c:447 SYSC_read fs/read_write.c:574 [inline] SyS_read+0xf2/0x210 fs/read_write.c:567 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #2 (&p->lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 seq_read+0xba/0x1120 fs/seq_file.c:165 proc_reg_read+0xee/0x1a0 fs/proc/inode.c:217 do_loop_readv_writev fs/read_write.c:695 [inline] do_loop_readv_writev fs/read_write.c:682 [inline] do_iter_read+0x3eb/0x5b0 fs/read_write.c:919 vfs_readv+0xc8/0x120 fs/read_write.c:981 kernel_readv fs/splice.c:361 [inline] default_file_splice_read+0x418/0x910 fs/splice.c:416 do_splice_to+0xfb/0x140 fs/splice.c:880 splice_direct_to_actor+0x207/0x730 fs/splice.c:952 do_splice_direct+0x164/0x210 fs/splice.c:1061 do_sendfile+0x47f/0xb30 fs/read_write.c:1441 SYSC_sendfile64 fs/read_write.c:1502 [inline] SyS_sendfile64+0xff/0x110 fs/read_write.c:1488 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #1 (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+0x64/0x260 fs/super.c:1342 sb_start_write include/linux/fs.h:1549 [inline] mnt_want_write+0x3a/0xb0 fs/namespace.c:386 ovl_create_object+0x75/0x1d0 fs/overlayfs/dir.c:538 lookup_open+0x77a/0x1750 fs/namei.c:3241 do_last fs/namei.c:3334 [inline] path_openat+0xe08/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_sys_open+0x296/0x410 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb -> #0 (&ovl_i_mutex_dir_key[depth]){++++}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 down_read+0x36/0x80 kernel/locking/rwsem.c:24 inode_lock_shared include/linux/fs.h:729 [inline] do_last fs/namei.c:3333 [inline] path_openat+0x149b/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_open_execat+0xd3/0x450 fs/exec.c:849 do_execveat_common+0x711/0x1f30 fs/exec.c:1755 do_execve fs/exec.c:1860 [inline] SYSC_execve fs/exec.c:1941 [inline] SyS_execve+0x3b/0x50 fs/exec.c:1936 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb other info that might help us debug this: Chain exists of: &ovl_i_mutex_dir_key[depth] --> &p->lock --> &sig->cred_guard_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sig->cred_guard_mutex); lock(&p->lock); lock(&sig->cred_guard_mutex); lock(&ovl_i_mutex_dir_key[depth]); *** DEADLOCK *** 1 lock held by syz-executor.4/24270: #0: (&sig->cred_guard_mutex){+.+.}, at: [] prepare_bprm_creds fs/exec.c:1404 [inline] #0: (&sig->cred_guard_mutex){+.+.}, at: [] do_execveat_common+0x319/0x1f30 fs/exec.c:1748 stack backtrace: CPU: 0 PID: 24270 Comm: syz-executor.4 Not tainted 4.14.218-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 down_read+0x36/0x80 kernel/locking/rwsem.c:24 inode_lock_shared include/linux/fs.h:729 [inline] do_last fs/namei.c:3333 [inline] path_openat+0x149b/0x2970 fs/namei.c:3569 do_filp_open+0x179/0x3c0 fs/namei.c:3603 do_open_execat+0xd3/0x450 fs/exec.c:849 do_execveat_common+0x711/0x1f30 fs/exec.c:1755 do_execve fs/exec.c:1860 [inline] SYSC_execve fs/exec.c:1941 [inline] SyS_execve+0x3b/0x50 fs/exec.c:1936 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x465b09 RSP: 002b:00007fe06e0a5188 EFLAGS: 00000246 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 000000000056c008 RCX: 0000000000465b09 RDX: 0000000020000340 RSI: 0000000020000180 RDI: 0000000020000100 RBP: 00000000004b069f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c008 R13: 00007fff4bc9975f R14: 00007fe06e0a5300 R15: 0000000000022000 FAT-fs (loop2): Invalid FSINFO signature: 0x00000000, 0x00000000 (sector = 1) audit: type=1804 audit(1612397082.389:288): pid=24287 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir558472752/syzkaller.pIcCL3/1381/file0/bus" dev="sda1" ino=16356 res=1 audit: type=1804 audit(1612397082.859:289): pid=24285 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.2" name="/root/syzkaller-testdir558472752/syzkaller.pIcCL3/1381/file0/bus" dev="sda1" ino=16356 res=1 overlayfs: failed to resolve './file0': -2 audit: type=1804 audit(1612397082.859:290): pid=24285 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir558472752/syzkaller.pIcCL3/1381/file0/bus" dev="sda1" ino=16356 res=1 FAT-fs (loop2): Invalid FSINFO signature: 0x00000000, 0x00000000 (sector = 1) audit: type=1804 audit(1612397083.109:291): pid=24343 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.2" name="/root/syzkaller-testdir558472752/syzkaller.pIcCL3/1382/file0/bus" dev="loop2" ino=117 res=1 FAT-fs (loop2): Invalid FSINFO signature: 0x00000000, 0x00000000 (sector = 1) overlayfs: unrecognized mount option "~d" or missing value overlayfs: unrecognized mount option "~d" or missing value TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. netlink: 4 bytes leftover after parsing attributes in process `syz-executor.1'. device bridge20 entered promiscuous mode device bridge_slave_0 left promiscuous mode bridge19: port 1(bridge_slave_0) entered disabled state bridge20: port 1(bridge_slave_0) entered blocking state bridge20: port 1(bridge_slave_0) entered disabled state device bridge_slave_0 entered promiscuous mode netlink: 4 bytes leftover after parsing attributes in process `syz-executor.1'. overlayfs: unrecognized mount option " Ÿwerdir=./file0" or missing value EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue audit: type=1800 audit(1612397087.449:292): pid=24693 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.0" name="file0" dev="loop0" ino=17 res=0 EXT4-fs error (device loop0): ext4_mb_generate_buddy:754: group 0, block bitmap and bg descriptor inconsistent: 50 vs 25 free clusters audit: type=1804 audit(1612397087.449:293): pid=24693 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.0" name="/root/syzkaller-testdir755827662/syzkaller.vPJ9Qv/1217/file0/file0" dev="loop0" ino=17 res=1 audit: type=1804 audit(1612397087.459:294): pid=24693 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.0" name="/root/syzkaller-testdir755827662/syzkaller.vPJ9Qv/1217/file0/file0" dev="loop0" ino=17 res=1 audit: type=1804 audit(1612397087.539:295): pid=24693 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.0" name="/root/syzkaller-testdir755827662/syzkaller.vPJ9Qv/1217/file0/file0" dev="loop0" ino=17 res=1 audit: type=1804 audit(1612397087.539:296): pid=24693 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.0" name="/root/syzkaller-testdir755827662/syzkaller.vPJ9Qv/1217/file0/file0" dev="loop0" ino=17 res=1 audit: type=1804 audit(1612397087.539:297): pid=24693 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="ToMToU" comm="syz-executor.0" name="/root/syzkaller-testdir755827662/syzkaller.vPJ9Qv/1217/file0/file0" dev="loop0" ino=17 res=1 ntfs: (device loop0): parse_options(): Unrecognized mount option context. ntfs: (device loop0): parse_options(): Unrecognized mount option fscontext. ntfs: (device loop0): parse_options(): Unrecognized mount option . ntfs: (device loop0): parse_options(): Unrecognized mount option context. netlink: 4 bytes leftover after parsing attributes in process `syz-executor.1'. device bridge21 entered promiscuous mode device bridge_slave_0 left promiscuous mode bridge20: port 1(bridge_slave_0) entered disabled state bridge21: port 1(bridge_slave_0) entered blocking state bridge21: port 1(bridge_slave_0) entered disabled state device bridge_slave_0 entered promiscuous mode netlink: 4 bytes leftover after parsing attributes in process `syz-executor.1'. IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready