audit: audit_backlog=65 > audit_backlog_limit=64 audit: audit_lost=329 audit_rate_limit=0 audit_backlog_limit=64 audit: backlog limit exceeded ====================================================== WARNING: possible circular locking dependency detected 4.14.78+ #25 Not tainted ------------------------------------------------------ syz-executor0/20911 is trying to acquire lock: (&sig->cred_guard_mutex){+.+.}, at: [] do_io_accounting+0x1d7/0x770 fs/proc/base.c:2731 but task is already holding lock: (&p->lock){+.+.}, at: [] seq_read+0xd4/0x11d0 fs/seq_file.c:165 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&p->lock){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xf5/0x1480 kernel/locking/mutex.c:893 seq_read+0xd4/0x11d0 fs/seq_file.c:165 do_loop_readv_writev fs/read_write.c:698 [inline] do_iter_read+0x3cc/0x580 fs/read_write.c:922 vfs_readv+0xe6/0x150 fs/read_write.c:984 kernel_readv fs/splice.c:361 [inline] default_file_splice_read+0x495/0x860 fs/splice.c:416 do_splice_to+0x102/0x150 fs/splice.c:880 do_splice fs/splice.c:1173 [inline] SYSC_splice fs/splice.c:1402 [inline] SyS_splice+0xf4d/0x12a0 fs/splice.c:1382 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #1 (&pipe->mutex/1){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xf5/0x1480 kernel/locking/mutex.c:893 __pipe_lock fs/pipe.c:88 [inline] fifo_open+0x156/0x9d0 fs/pipe.c:921 do_dentry_open+0x426/0xda0 fs/open.c:764 vfs_open+0x11c/0x210 fs/open.c:878 do_last fs/namei.c:3408 [inline] path_openat+0x4eb/0x23a0 fs/namei.c:3550 do_filp_open+0x197/0x270 fs/namei.c:3584 do_open_execat+0x10d/0x5b0 fs/exec.c:849 do_execveat_common.isra.14+0x6cb/0x1d60 fs/exec.c:1740 do_execve fs/exec.c:1847 [inline] SYSC_execve fs/exec.c:1928 [inline] SyS_execve+0x34/0x40 fs/exec.c:1923 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #0 (&sig->cred_guard_mutex){+.+.}: lock_acquire+0x10f/0x380 kernel/locking/lockdep.c:3991 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xf5/0x1480 kernel/locking/mutex.c:893 do_io_accounting+0x1d7/0x770 fs/proc/base.c:2731 proc_single_show+0xf1/0x160 fs/proc/base.c:762 seq_read+0x4e0/0x11d0 fs/seq_file.c:237 do_loop_readv_writev fs/read_write.c:698 [inline] do_iter_read+0x3cc/0x580 fs/read_write.c:922 vfs_readv+0xe6/0x150 fs/read_write.c:984 do_preadv+0x187/0x230 fs/read_write.c:1068 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 other info that might help us debug this: Chain exists of: &sig->cred_guard_mutex --> &pipe->mutex/1 --> &p->lock 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-executor0/20911: #0: (&p->lock){+.+.}, at: [] seq_read+0xd4/0x11d0 fs/seq_file.c:165 stack backtrace: CPU: 1 PID: 20911 Comm: syz-executor0 Not tainted 4.14.78+ #25 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 print_circular_bug.isra.18.cold.43+0x2d3/0x40c kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2ff9/0x4320 kernel/locking/lockdep.c:3487 lock_acquire+0x10f/0x380 kernel/locking/lockdep.c:3991 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xf5/0x1480 kernel/locking/mutex.c:893 do_io_accounting+0x1d7/0x770 fs/proc/base.c:2731 proc_single_show+0xf1/0x160 fs/proc/base.c:762 seq_read+0x4e0/0x11d0 fs/seq_file.c:237 do_loop_readv_writev fs/read_write.c:698 [inline] do_iter_read+0x3cc/0x580 fs/read_write.c:922 vfs_readv+0xe6/0x150 fs/read_write.c:984 do_preadv+0x187/0x230 fs/read_write.c:1068 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457569 RSP: 002b:00007f338eb72c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457569 RDX: 00000000000001a1 RSI: 00000000200017c0 RDI: 0000000000000006 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f338eb736d4 R13: 00000000004c3088 R14: 00000000004d4a40 R15: 00000000ffffffff kauditd_printk_skb: 1843 callbacks suppressed audit: type=1400 audit(1540414592.085:37064): avc: denied { map } for pid=21056 comm="modprobe" path="/bin/kmod" dev="sda1" ino=1440 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414592.095:37065): avc: denied { map } for pid=21056 comm="modprobe" path="/bin/kmod" dev="sda1" ino=1440 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414592.095:37066): avc: denied { map } for pid=21056 comm="modprobe" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414592.095:37067): avc: denied { map } for pid=21056 comm="modprobe" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414592.095:37068): avc: denied { map } for pid=21056 comm="modprobe" path="/etc/ld.so.cache" dev="sda1" ino=2503 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414592.095:37069): avc: denied { map } for pid=21056 comm="modprobe" path="/lib/x86_64-linux-gnu/libkmod.so.2.1.3" dev="sda1" ino=2811 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414592.095:37070): avc: denied { map } for pid=21056 comm="modprobe" path="/lib/x86_64-linux-gnu/libkmod.so.2.1.3" dev="sda1" ino=2811 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414592.105:37071): avc: denied { map } for pid=21056 comm="modprobe" path="/lib/x86_64-linux-gnu/libc-2.13.so" dev="sda1" ino=2784 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414592.105:37072): avc: denied { map } for pid=21056 comm="modprobe" path="/lib/x86_64-linux-gnu/libc-2.13.so" dev="sda1" ino=2784 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414592.115:37073): avc: denied { map } for pid=21057 comm="modprobe" path="/bin/kmod" dev="sda1" ino=1440 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 kauditd_printk_skb: 545 callbacks suppressed audit: type=1400 audit(1540414597.505:37619): avc: denied { map } for pid=21223 comm="modprobe" path="/bin/kmod" dev="sda1" ino=1440 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414597.505:37620): avc: denied { map } for pid=21223 comm="modprobe" path="/bin/kmod" dev="sda1" ino=1440 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414597.515:37621): avc: denied { map } for pid=21223 comm="modprobe" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414597.515:37622): avc: denied { map } for pid=21223 comm="modprobe" path="/lib/x86_64-linux-gnu/ld-2.13.so" dev="sda1" ino=2668 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414597.515:37623): avc: denied { map } for pid=21223 comm="modprobe" path="/etc/ld.so.cache" dev="sda1" ino=2503 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414597.515:37624): avc: denied { map } for pid=21223 comm="modprobe" path="/lib/x86_64-linux-gnu/libkmod.so.2.1.3" dev="sda1" ino=2811 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414597.515:37625): avc: denied { map } for pid=21223 comm="modprobe" path="/lib/x86_64-linux-gnu/libkmod.so.2.1.3" dev="sda1" ino=2811 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414597.515:37626): avc: denied { map } for pid=21223 comm="modprobe" path="/lib/x86_64-linux-gnu/libc-2.13.so" dev="sda1" ino=2784 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414597.515:37627): avc: denied { map } for pid=21223 comm="modprobe" path="/lib/x86_64-linux-gnu/libc-2.13.so" dev="sda1" ino=2784 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1540414597.535:37628): avc: denied { map } for pid=21224 comm="modprobe" path="/bin/kmod" dev="sda1" ino=1440 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1