====================================================== WARNING: possible circular locking dependency detected 4.14.98+ #6 Not tainted ------------------------------------------------------ syz-executor3/18262 is trying to acquire lock: (&pipe->mutex/1){+.+.}, at: [] __pipe_lock fs/pipe.c:88 [inline] (&pipe->mutex/1){+.+.}, at: [] fifo_open+0x156/0x9b0 fs/pipe.c:921 but task is already holding lock: (&sig->cred_guard_mutex){+.+.}, at: [] prepare_bprm_creds+0x51/0x110 fs/exec.c:1389 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sig->cred_guard_mutex){+.+.}: -> #0 (&pipe->mutex/1){+.+.}: other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sig->cred_guard_mutex); lock(&pipe->mutex/1); lock(&sig->cred_guard_mutex); lock(&pipe->mutex/1); *** DEADLOCK *** 1 lock held by syz-executor3/18262: #0: (&sig->cred_guard_mutex){+.+.}, at: [] prepare_bprm_creds+0x51/0x110 fs/exec.c:1389 stack backtrace: CPU: 1 PID: 18262 Comm: syz-executor3 Not tainted 4.14.98+ #6 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x10e lib/dump_stack.c:53 print_circular_bug.isra.0.cold+0x2dc/0x425 kernel/locking/lockdep.c:1258 loop2: p1 p2 p3 p4 < > kauditd_printk_skb: 291 callbacks suppressed audit: type=1400 audit(1549635240.994:44449): avc: denied { map } for pid=18293 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1549635241.034:44450): avc: denied { map } for pid=18293 comm="blkid" 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(1549635241.034:44451): avc: denied { map } for pid=18293 comm="blkid" 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(1549635241.034:44452): avc: denied { map } for pid=18293 comm="blkid" 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(1549635241.054:44453): avc: denied { map } for pid=18292 comm="blkid" path="/lib/x86_64-linux-gnu/libuuid.so.1.3.0" dev="sda1" ino=2819 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1549635241.084:44454): avc: denied { map } for pid=18293 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1549635241.084:44455): avc: denied { map } for pid=18293 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1549635241.094:44456): avc: denied { map } for pid=18293 comm="blkid" 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(1549635241.094:44457): avc: denied { map } for pid=18293 comm="blkid" 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(1549635241.114:44458): avc: denied { map } for pid=18302 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 loop2: p1 p2 p3 p4 < > loop2: p1 p2 p3 p4 < > loop2: p1 p2 p3 p4 < > kauditd_printk_skb: 298 callbacks suppressed audit: type=1400 audit(1549635246.154:44757): avc: denied { map } for pid=18417 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1549635246.154:44758): avc: denied { map } for pid=18417 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1549635246.184:44759): avc: denied { map } for pid=18417 comm="blkid" 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(1549635246.194:44760): avc: denied { map } for pid=18417 comm="blkid" 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(1549635246.224:44761): avc: denied { map } for pid=18417 comm="blkid" 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(1549635246.244:44762): avc: denied { map } for pid=18417 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1549635246.254:44763): avc: denied { map } for pid=18417 comm="blkid" path="/lib/x86_64-linux-gnu/libblkid.so.1.1.0" dev="sda1" ino=2825 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 audit: type=1400 audit(1549635246.284:44764): avc: denied { map } for pid=18417 comm="blkid" 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 loop2: p1 p2 p3 p4 < > audit: type=1400 audit(1549635246.294:44765): avc: denied { map } for pid=18417 comm="blkid" 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(1549635246.294:44766): avc: denied { map } for pid=18424 comm="blkid" path="/sbin/blkid" dev="sda1" ino=16128 scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1