====================================================== WARNING: possible circular locking dependency detected 4.19.211-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/25418 is trying to acquire lock: 00000000db8617a5 (&sig->cred_guard_mutex){+.+.}, at: lock_trace fs/proc/base.c:402 [inline] 00000000db8617a5 (&sig->cred_guard_mutex){+.+.}, at: proc_pid_syscall+0xb8/0x2f0 fs/proc/base.c:635 but task is already holding lock: 00000000bbedbe98 (&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_execveat+0x3d/0x50 fs/exec.c:1907 __do_sys_execveat fs/exec.c:1988 [inline] __se_sys_execveat fs/exec.c:1980 [inline] __x64_sys_execveat+0xe1/0x120 fs/exec.c:1980 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe netlink: 4 bytes leftover after parsing attributes in process `syz-executor.4'. -> #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 netlink: 'syz-executor.4': attribute type 25 has an invalid length. 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: netlink: 8 bytes leftover after parsing attributes in process `syz-executor.4'. 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.0/25418: #0: 00000000bbedbe98 (&p->lock){+.+.}, at: seq_read+0x6b/0x11c0 fs/seq_file.c:164 stack backtrace: CPU: 0 PID: 25418 Comm: syz-executor.0 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 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: 0033:0x7fad4a0280a9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fad4859a168 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007fad4a147f80 RCX: 00007fad4a0280a9 RDX: 0000000000000001 RSI: 0000000020000440 RDI: 0000000000000004 RBP: 00007fad4a083ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcce37c87f R14: 00007fad4859a300 R15: 0000000000022000 EXT4-fs (loop3): mounted filesystem without journal. Opts: barrier,noquota,abort,nodiscard,usrjquota=,,errors=continue netlink: 12 bytes leftover after parsing attributes in process `syz-executor.2'. EXT4-fs (loop3): Test dummy encryption mount option ignored EXT4-fs (loop3): Unsupported blocksize for fs encryption netlink: 12 bytes leftover after parsing attributes in process `syz-executor.2'. IPVS: ftp: loaded support on port[0] = 21 TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. kauditd_printk_skb: 58 callbacks suppressed audit: type=1326 audit(1672016121.491:130): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=25599 comm="syz-executor.5" exe="/root/syz-executor.5" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7faf285660a9 code=0x0 IPVS: ftp: loaded support on port[0] = 21 netlink: 12 bytes leftover after parsing attributes in process `syz-executor.2'. audit: type=1800 audit(1672016122.261:131): pid=25659 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=collect_data cause=failed(directio) comm="syz-executor.5" name="file0" dev="sda1" ino=13844 res=0 netlink: 12 bytes leftover after parsing attributes in process `syz-executor.2'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 4 bytes leftover after parsing attributes in process `syz-executor.1'. audit: type=1326 audit(1672016124.891:132): auid=4294967295 uid=0 gid=0 ses=4294967295 subj==unconfined pid=25829 comm="syz-executor.0" exe="/root/syz-executor.0" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7fad4a0280a9 code=0x0 device batadv1 entered promiscuous mode 8021q: adding VLAN 0 to HW filter on device batadv1 batman_adv: batadv1: Adding interface: team0 batman_adv: batadv1: The MTU of interface team0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. batman_adv: batadv1: Interface activated: team0 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'. device batadv1 entered promiscuous mode 8021q: adding VLAN 0 to HW filter on device batadv1 netlink: 4 bytes leftover after parsing attributes in process `syz-executor.1'. device batadv2 entered promiscuous mode 8021q: adding VLAN 0 to HW filter on device batadv2 netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. batman_adv: batadv1: Adding interface: team0 batman_adv: batadv1: The MTU of interface team0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. batman_adv: batadv1: Not using interface team0 (retrying later): interface not active batman_adv: batadv1: Interface deactivated: team0 batman_adv: batadv1: Removing interface: team0 batman_adv: batadv2: Adding interface: team0 batman_adv: batadv2: The MTU of interface team0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. batman_adv: batadv2: Interface activated: team0 netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'. device batadv2 entered promiscuous mode 8021q: adding VLAN 0 to HW filter on device batadv2 netlink: 4 bytes leftover after parsing attributes in process `syz-executor.1'. device batadv3 entered promiscuous mode 8021q: adding VLAN 0 to HW filter on device batadv3 batman_adv: batadv1: Removing interface: team0 batman_adv: batadv2: Adding interface: team0 audit: type=1804 audit(1672016125.791:133): pid=25996 uid=0 auid=4294967295 ses=4294967295 subj==unconfined op=invalid_pcr cause=open_writers comm="syz-executor.3" name="/root/syzkaller-testdir853521991/syzkaller.AUM6dV/790/file0" dev="sda1" ino=14755 res=1 batman_adv: batadv2: The MTU of interface team0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. batman_adv: batadv2: Not using interface team0 (retrying later): interface not active batman_adv: batadv2: Interface deactivated: team0 batman_adv: batadv2: Removing interface: team0 batman_adv: batadv3: Adding interface: team0 batman_adv: batadv3: The MTU of interface team0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. batman_adv: batadv3: Interface activated: team0 netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'. device batadv3 entered promiscuous mode 8021q: adding VLAN 0 to HW filter on device batadv3 batman_adv: batadv2: Removing interface: team0 batman_adv: batadv3: Adding interface: team0 batman_adv: batadv3: The MTU of interface team0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. batman_adv: batadv3: Not using interface team0 (retrying later): interface not active device batadv4 entered promiscuous mode 8021q: adding VLAN 0 to HW filter on device batadv4 batman_adv: batadv3: Interface deactivated: team0 batman_adv: batadv3: Removing interface: team0 batman_adv: batadv4: Adding interface: team0 batman_adv: batadv4: The MTU of interface team0 is too small (1500) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem. batman_adv: batadv4: Interface activated: team0 IPVS: ftp: loaded support on port[0] = 21 nla_parse: 11 callbacks suppressed netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 16 bytes leftover after parsing attributes in process `syz-executor.5'. IPv6: sit1: Disabled Multicast RS