====================================================== WARNING: possible circular locking dependency detected 4.14.281-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/12820 is trying to acquire lock: (&sig->cred_guard_mutex){+.+.}, at: [] do_io_accounting fs/proc/base.c:2738 [inline] (&sig->cred_guard_mutex){+.+.}, at: [] proc_tid_io_accounting+0x184/0x290 fs/proc/base.c:2781 but task is already holding lock: (&p->lock){+.+.}, at: [] seq_read+0xba/0x1180 fs/seq_file.c:168 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:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 seq_read+0xba/0x1180 fs/seq_file.c:168 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 -> #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+0x64/0x260 fs/super.c:1342 sb_start_write include/linux/fs.h:1551 [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 -> #1 (&ovl_i_mutex_dir_key[depth]){++++}: 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 -> #0 (&sig->cred_guard_mutex){+.+.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 do_io_accounting fs/proc/base.c:2738 [inline] proc_tid_io_accounting+0x184/0x290 fs/proc/base.c:2781 proc_single_show+0xe7/0x150 fs/proc/base.c:761 seq_read+0x4e4/0x1180 fs/seq_file.c:240 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 do_preadv fs/read_write.c:1065 [inline] SYSC_preadv fs/read_write.c:1115 [inline] SyS_preadv+0x15a/0x200 fs/read_write.c:1110 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: &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.0/12820: #0: (&p->lock){+.+.}, at: [] seq_read+0xba/0x1180 fs/seq_file.c:168 stack backtrace: CPU: 0 PID: 12820 Comm: syz-executor.0 Not tainted 4.14.281-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 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xc4/0x1310 kernel/locking/mutex.c:893 do_io_accounting fs/proc/base.c:2738 [inline] proc_tid_io_accounting+0x184/0x290 fs/proc/base.c:2781 proc_single_show+0xe7/0x150 fs/proc/base.c:761 seq_read+0x4e4/0x1180 fs/seq_file.c:240 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 do_preadv fs/read_write.c:1065 [inline] SYSC_preadv fs/read_write.c:1115 [inline] SyS_preadv+0x15a/0x200 fs/read_write.c:1110 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f92ec584109 RSP: 002b:00007f92eaef9168 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007f92ec696f60 RCX: 00007f92ec584109 RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000000005 RBP: 00007f92ec5de08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd1462d6ef R14: 00007f92eaef9300 R15: 0000000000022000 unregister_netdevice: waiting for ip6gre0 to become free. Usage count = -1 audit: type=1804 audit(1653693109.535:25): pid=12835 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.5" name="/root/syzkaller-testdir427273665/syzkaller.dufaFB/111/file0" dev="sda1" ino=14332 res=1 8021q: adding VLAN 0 to HW filter on device team0 bond0: Enslaving team0 as an active interface with an up link bond0: Releasing backup interface team0 bridge0: port 3(team0) entered blocking state bridge0: port 3(team0) entered disabled state device team0 entered promiscuous mode device team_slave_0 entered promiscuous mode device team_slave_1 entered promiscuous mode EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue device team0 left promiscuous mode device team_slave_0 left promiscuous mode EXT4-fs error (device loop5): ext4_mb_generate_buddy:754: group 0, block bitmap and bg descriptor inconsistent: 50 vs 25 free clusters device team_slave_1 left promiscuous mode bridge0: port 3(team0) entered disabled state 8021q: adding VLAN 0 to HW filter on device team0 EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue bond0: Enslaving team0 as an active interface with an up link bond0: Releasing backup interface team0 bridge0: port 3(team0) entered blocking state bridge0: port 3(team0) entered disabled state EXT4-fs error (device loop5): ext4_mb_generate_buddy:754: group 0, block bitmap and bg descriptor inconsistent: 50 vs 25 free clusters device team0 entered promiscuous mode device team_slave_0 entered promiscuous mode device team_slave_1 entered promiscuous mode device team0 left promiscuous mode device team_slave_0 left promiscuous mode device team_slave_1 left promiscuous mode bridge0: port 3(team0) entered disabled state EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue 8021q: adding VLAN 0 to HW filter on device team0 EXT4-fs error (device loop5): ext4_mb_generate_buddy:754: group 0, block bitmap and bg descriptor inconsistent: 50 vs 25 free clusters EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue bond0: Enslaving team0 as an active interface with an up link bond0: Releasing backup interface team0 bridge0: port 3(team0) entered blocking state bridge0: port 3(team0) entered disabled state device team0 entered promiscuous mode EXT4-fs error (device loop3): ext4_mb_generate_buddy:754: group 0, block bitmap and bg descriptor inconsistent: 50 vs 25 free clusters device team_slave_0 entered promiscuous mode device team_slave_1 entered promiscuous mode EXT4-fs (loop5): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs error (device loop5): ext4_mb_generate_buddy:754: group 0, block bitmap and bg descriptor inconsistent: 50 vs 25 free clusters EXT4-fs error (device loop3): ext4_mb_generate_buddy:754: group 0, block bitmap and bg descriptor inconsistent: 50 vs 25 free clusters EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue device team0 left promiscuous mode device team_slave_0 left promiscuous mode device team_slave_1 left promiscuous mode bridge0: port 3(team0) entered disabled state EXT4-fs error (device loop3): ext4_mb_generate_buddy:754: group 0, block bitmap and bg descriptor inconsistent: 50 vs 25 free clusters 8021q: adding VLAN 0 to HW filter on device team0 bond0: Enslaving team0 as an active interface with an up link bond0: Releasing backup interface team0 bridge0: port 3(team0) entered blocking state bridge0: port 3(team0) entered disabled state device team0 entered promiscuous mode device team_slave_0 entered promiscuous mode device team_slave_1 entered promiscuous mode syz-executor.1 (13204) used greatest stack depth: 23800 bytes left audit: type=1800 audit(1653693116.456:26): pid=13346 uid=0 auid=4294967295 ses=4294967295 op="collect_data" cause="failed(directio)" comm="syz-executor.0" name="file0" dev="sda1" ino=14394 res=0 audit: type=1804 audit(1653693116.476:27): pid=13354 uid=0 auid=4294967295 ses=4294967295 op="invalid_pcr" cause="open_writers" comm="syz-executor.0" name="/root/syzkaller-testdir3828707222/syzkaller.BvU6uv/124/file0" dev="sda1" ino=14394 res=1 netlink: 32 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 32 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 32 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 32 bytes leftover after parsing attributes in process `syz-executor.3'. VFS: Can't find a Minix filesystem V1 | V2 | V3 on device loop1. print_req_error: I/O error, dev loop1, sector 0 Buffer I/O error on dev loop1, logical block 0, async page read print_req_error: I/O error, dev loop1, sector 4 Buffer I/O error on dev loop1, logical block 2, async page read print_req_error: I/O error, dev loop1, sector 6 Buffer I/O error on dev loop1, logical block 3, async page read VFS: Can't find a Minix filesystem V1 | V2 | V3 on device loop1. VFS: Can't find a Minix filesystem V1 | V2 | V3 on device loop1. print_req_error: I/O error, dev loop1, sector 0 Buffer I/O error on dev loop1, logical block 0, async page read print_req_error: I/O error, dev loop1, sector 4 Buffer I/O error on dev loop1, logical block 2, async page read print_req_error: I/O error, dev loop1, sector 6 Buffer I/O error on dev loop1, logical block 3, async page read VFS: Can't find a Minix filesystem V1 | V2 | V3 on device loop5. VFS: Can't find a Minix filesystem V1 | V2 | V3 on device loop1. EXT4-fs warning (device sda1): verify_group_input:136: Cannot add at group 3125 (only 16 groups) VFS: Can't find a Minix filesystem V1 | V2 | V3 on device loop5. VFS: Can't find a Minix filesystem V1 | V2 | V3 on device loop5. EXT4-fs (loop3): warning: mounting unchecked fs, running e2fsck is recommended EXT4-fs warning (device loop3): ext4_update_dynamic_rev:793: updating to rev 1 because of new feature flag, running e2fsck is recommended EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue print_req_error: I/O error, dev loop5, sector 0 Buffer I/O error on dev loop5, logical block 0, async page read print_req_error: I/O error, dev loop5, sector 4 Buffer I/O error on dev loop5, logical block 2, async page read print_req_error: I/O error, dev loop5, sector 6 Buffer I/O error on dev loop5, logical block 3, async page read EXT4-fs (loop3): warning: mounting unchecked fs, running e2fsck is recommended EXT4-fs warning (device loop3): ext4_update_dynamic_rev:793: updating to rev 1 because of new feature flag, running e2fsck is recommended EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue EXT4-fs (loop1): mounting ext2 file system using the ext4 subsystem print_req_error: I/O error, dev loop3, sector 0 EXT4-fs (loop1): mounted filesystem without journal. Opts: ,errors=continue device vxlan0 entered promiscuous mode EXT4-fs (loop1): re-mounted. Opts: (null)