====================================================== WARNING: possible circular locking dependency detected 4.19.196-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.1/23843 is trying to acquire lock: 00000000a9f14082 (&sig->cred_guard_mutex){+.+.}, at: do_io_accounting fs/proc/base.c:2750 [inline] 00000000a9f14082 (&sig->cred_guard_mutex){+.+.}, at: proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 but task is already holding lock: 00000000cd693191 (&p->lock){+.+.}, at: seq_read+0x6b/0x1160 fs/seq_file.c:161 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&p->lock){+.+.}: seq_read+0x6b/0x1160 fs/seq_file.c:161 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){.+.+}: IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready file_start_write include/linux/fs.h:2779 [inline] ovl_write_iter+0x932/0xb40 fs/overlayfs/file.c:282 call_write_iter include/linux/fs.h:1821 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x51b/0x770 fs/read_write.c:487 vfs_write+0x1f3/0x540 fs/read_write.c:549 ksys_write+0x12b/0x2a0 fs/read_write.c:599 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&ovl_i_mutex_key[depth]){+.+.}: inode_lock include/linux/fs.h:748 [inline] process_measurement+0x926/0x1440 security/integrity/ima/ima_main.c:205 ima_file_check+0xb9/0x100 security/integrity/ima/ima_main.c:391 do_last fs/namei.c:3425 [inline] path_openat+0x7e4/0x2df0 fs/namei.c:3537 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 chnl_net:chnl_net_open(): err: Unable to register and open device, Err:-19 -> #0 (&sig->cred_guard_mutex){+.+.}: caif:caif_disconnect_client(): nothing to disconnect __mutex_lock_common kernel/locking/mutex.c:938 [inline] __mutex_lock+0xd7/0x1200 kernel/locking/mutex.c:1083 do_io_accounting fs/proc/base.c:2750 [inline] proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4be/0x1160 fs/seq_file.c:229 __vfs_read+0xf7/0x750 fs/read_write.c:416 vfs_read+0x194/0x3c0 fs/read_write.c:452 ksys_read+0x12b/0x2a0 fs/read_write.c:579 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 *** 2 locks held by syz-executor.1/23843: #0: 000000007fc97a9c (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 #1: 00000000cd693191 (&p->lock){+.+.}, at: seq_read+0x6b/0x1160 fs/seq_file.c:161 stack backtrace: CPU: 1 PID: 23843 Comm: syz-executor.1 Not tainted 4.19.196-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:938 [inline] __mutex_lock+0xd7/0x1200 kernel/locking/mutex.c:1083 do_io_accounting fs/proc/base.c:2750 [inline] proc_tid_io_accounting+0x184/0x2b0 fs/proc/base.c:2793 proc_single_show+0xeb/0x170 fs/proc/base.c:755 seq_read+0x4be/0x1160 fs/seq_file.c:229 __vfs_read+0xf7/0x750 fs/read_write.c:416 vfs_read+0x194/0x3c0 fs/read_write.c:452 ksys_read+0x12b/0x2a0 fs/read_write.c:579 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4665d9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fa65ebe9188 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 00007ffef9d6112f R14: 00007fa65ebe9300 R15: 0000000000022000 chnl_net:chnl_flowctrl_cb(): NET flowctrl func called flow: CLOSE/DEINIT chnl_net:chnl_net_open(): state disconnected A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check. EXT4-fs: failed to create workqueue EXT4-fs (loop3): mount failed IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready chnl_net:chnl_net_open(): err: Unable to register and open device, Err:-19 caif:caif_disconnect_client(): nothing to disconnect chnl_net:chnl_flowctrl_cb(): NET flowctrl func called flow: CLOSE/DEINIT chnl_net:chnl_net_open(): state disconnected A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check. IPv6: ADDRCONF(NETDEV_CHANGE): vcan0: link becomes ready chnl_net:chnl_net_open(): err: Unable to register and open device, Err:-19 caif:caif_disconnect_client(): nothing to disconnect chnl_net:chnl_flowctrl_cb(): NET flowctrl func called flow: CLOSE/DEINIT chnl_net:chnl_net_open(): state disconnected A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check. EXT4-fs (loop3): mounted filesystem without journal. Opts: ,errors=continue ieee802154 phy0 wpan0: encryption failed: -22 ieee802154 phy1 wpan1: encryption failed: -22 overlayfs: filesystem on './file0' not supported as upperdir FAT-fs (loop4): bogus number of reserved sectors FAT-fs (loop4): Can't find a valid FAT filesystem netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'.