====================================================== [ INFO: possible circular locking dependency detected ] 4.9.141+ #1 Not tainted ------------------------------------------------------- syz-executor.0/8267 is trying to acquire lock: (&sig->cred_guard_mutex){+.+.+.}, at: [] lock_trace+0x44/0xc0 fs/proc/base.c:431 but task is already holding lock: (&p->lock){+.+.+.}, at: [] seq_read+0xdd/0x12d0 fs/seq_file.c:178 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 __mutex_lock_common kernel/locking/mutex.c:521 [inline] mutex_lock_nested+0xc0/0x900 kernel/locking/mutex.c:621 seq_read+0xdd/0x12d0 fs/seq_file.c:178 proc_reg_read+0xfd/0x180 fs/proc/inode.c:203 do_loop_readv_writev.part.1+0xd5/0x280 fs/read_write.c:718 do_loop_readv_writev fs/read_write.c:707 [inline] do_readv_writev+0x56e/0x7b0 fs/read_write.c:873 vfs_readv+0x84/0xc0 fs/read_write.c:897 kernel_readv fs/splice.c:363 [inline] default_file_splice_read+0x451/0x7f0 fs/splice.c:435 do_splice_to+0x10c/0x170 fs/splice.c:899 do_splice fs/splice.c:1192 [inline] SYSC_splice fs/splice.c:1416 [inline] SyS_splice+0x10d2/0x14d0 fs/splice.c:1399 do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 __mutex_lock_common kernel/locking/mutex.c:521 [inline] mutex_lock_nested+0xc0/0x900 kernel/locking/mutex.c:621 __pipe_lock fs/pipe.c:87 [inline] fifo_open+0x15c/0x9e0 fs/pipe.c:921 do_dentry_open+0x3ef/0xc90 fs/open.c:766 vfs_open+0x11c/0x210 fs/open.c:879 do_last fs/namei.c:3410 [inline] path_openat+0x542/0x2790 fs/namei.c:3534 do_filp_open+0x197/0x270 fs/namei.c:3568 do_open_execat+0x10f/0x640 fs/exec.c:844 do_execveat_common.isra.14+0x687/0x1ed0 fs/exec.c:1723 do_execve fs/exec.c:1829 [inline] SYSC_execve fs/exec.c:1910 [inline] SyS_execve+0x42/0x50 fs/exec.c:1905 do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb check_prev_add kernel/locking/lockdep.c:1828 [inline] check_prevs_add kernel/locking/lockdep.c:1938 [inline] validate_chain kernel/locking/lockdep.c:2265 [inline] __lock_acquire+0x3189/0x4a10 kernel/locking/lockdep.c:3345 lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 __mutex_lock_common kernel/locking/mutex.c:521 [inline] mutex_lock_killable_nested+0xcc/0x9f0 kernel/locking/mutex.c:641 lock_trace+0x44/0xc0 fs/proc/base.c:431 proc_pid_personality+0x1c/0xc0 fs/proc/base.c:2878 proc_single_show+0xfd/0x170 fs/proc/base.c:785 seq_read+0x4b6/0x12d0 fs/seq_file.c:240 do_loop_readv_writev.part.1+0xd5/0x280 fs/read_write.c:718 do_loop_readv_writev fs/read_write.c:707 [inline] do_readv_writev+0x56e/0x7b0 fs/read_write.c:873 vfs_readv+0x84/0xc0 fs/read_write.c:897 kernel_readv fs/splice.c:363 [inline] default_file_splice_read+0x451/0x7f0 fs/splice.c:435 do_splice_to+0x10c/0x170 fs/splice.c:899 splice_direct_to_actor+0x23f/0x7e0 fs/splice.c:971 do_splice_direct+0x1a3/0x270 fs/splice.c:1080 do_sendfile+0x4f0/0xc30 fs/read_write.c:1393 SYSC_sendfile64 fs/read_write.c:1454 [inline] SyS_sendfile64+0x144/0x160 fs/read_write.c:1440 do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb other info that might help us debug this: Chain exists of: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&p->lock); lock(&pipe->mutex/1); lock(&p->lock); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 1 lock held by syz-executor.0/8267: #0: (&p->lock){+.+.+.}, at: [] seq_read+0xdd/0x12d0 fs/seq_file.c:178 stack backtrace: CPU: 0 PID: 8267 Comm: syz-executor.0 Not tainted 4.9.141+ #1 ffff8801d302efb8 ffffffff81b42e79 ffffffff83ca9d80 ffffffff83ca4920 ffffffff83ca2fd0 ffff8801d52e5010 ffff8801d52e4740 ffff8801d302f000 ffffffff813fee40 0000000000000001 00000000d52e4ff0 0000000000000001 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] print_circular_bug.cold.36+0x2f7/0x432 kernel/locking/lockdep.c:1202 [] check_prev_add kernel/locking/lockdep.c:1828 [inline] [] check_prevs_add kernel/locking/lockdep.c:1938 [inline] [] validate_chain kernel/locking/lockdep.c:2265 [inline] [] __lock_acquire+0x3189/0x4a10 kernel/locking/lockdep.c:3345 [] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756 [] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [] mutex_lock_killable_nested+0xcc/0x9f0 kernel/locking/mutex.c:641 [] lock_trace+0x44/0xc0 fs/proc/base.c:431 [] proc_pid_personality+0x1c/0xc0 fs/proc/base.c:2878 [] proc_single_show+0xfd/0x170 fs/proc/base.c:785 [] seq_read+0x4b6/0x12d0 fs/seq_file.c:240 [] do_loop_readv_writev.part.1+0xd5/0x280 fs/read_write.c:718 [] do_loop_readv_writev fs/read_write.c:707 [inline] [] do_readv_writev+0x56e/0x7b0 fs/read_write.c:873 [] vfs_readv+0x84/0xc0 fs/read_write.c:897 [] kernel_readv fs/splice.c:363 [inline] [] default_file_splice_read+0x451/0x7f0 fs/splice.c:435 [] do_splice_to+0x10c/0x170 fs/splice.c:899 [] splice_direct_to_actor+0x23f/0x7e0 fs/splice.c:971 [] do_splice_direct+0x1a3/0x270 fs/splice.c:1080 [] do_sendfile+0x4f0/0xc30 fs/read_write.c:1393 [] SYSC_sendfile64 fs/read_write.c:1454 [inline] [] SyS_sendfile64+0x144/0x160 fs/read_write.c:1440 [] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Dead loop on virtual device ip6_vti0, fix it urgently! Dead loop on virtual device ip6_vti0, fix it urgently! blk_update_request: 379 callbacks suppressed blk_update_request: I/O error, dev loop0, sector 0 buffer_io_error: 379 callbacks suppressed Buffer I/O error on dev loop0, logical block 0, lost async page write blk_update_request: I/O error, dev loop0, sector 8 Buffer I/O error on dev loop0, logical block 1, lost async page write blk_update_request: I/O error, dev loop0, sector 16 Buffer I/O error on dev loop0, logical block 2, lost async page write blk_update_request: I/O error, dev loop0, sector 24 Buffer I/O error on dev loop0, logical block 3, lost async page write blk_update_request: I/O error, dev loop0, sector 32 Buffer I/O error on dev loop0, logical block 4, lost async page write blk_update_request: I/O error, dev loop0, sector 40 Buffer I/O error on dev loop0, logical block 5, lost async page write blk_update_request: I/O error, dev loop0, sector 48 Buffer I/O error on dev loop0, logical block 6, lost async page write blk_update_request: I/O error, dev loop0, sector 56 Buffer I/O error on dev loop0, logical block 7, lost async page write blk_update_request: I/O error, dev loop0, sector 64 Buffer I/O error on dev loop0, logical block 8, lost async page write blk_update_request: I/O error, dev loop0, sector 72 Buffer I/O error on dev loop0, logical block 9, lost async page write Dead loop on virtual device ip6_vti0, fix it urgently! Dead loop on virtual device ip6_vti0, fix it urgently! qtaguid: iface_stat: create(lo): no inet dev qtaguid: iface_stat: create6(lo): no inet dev IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready qtaguid: iface_stat: create6(lo): no inet dev IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready qtaguid: iface_stat: create6(lo): no inet dev netlink: 36 bytes leftover after parsing attributes in process `syz-executor.5'. selinux_nlmsg_perm: 72 callbacks suppressed SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=8567 comm=syz-executor.5 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=8567 comm=syz-executor.5 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=8567 comm=syz-executor.5 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=8567 comm=syz-executor.5 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=8567 comm=syz-executor.5 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=8567 comm=syz-executor.5 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=8567 comm=syz-executor.5 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=8567 comm=syz-executor.5 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=8567 comm=syz-executor.5 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=8567 comm=syz-executor.5 IPv6: NLM_F_CREATE should be specified when creating new route netlink: 12 bytes leftover after parsing attributes in process `syz-executor.5'. PF_BRIDGE: RTM_NEWNEIGH with invalid address Dead loop on virtual device ip6_vti0, fix it urgently! netlink: 4 bytes leftover after parsing attributes in process `syz-executor.0'.