======================================================
WARNING: possible circular locking dependency detected
4.14.109+ #46 Not tainted
------------------------------------------------------
syz-executor.4/3972 is trying to acquire lock:
(&p->lock){+.+.}, at: [<000000007c0d65c5>] seq_read+0xcd/0x1180 fs/seq_file.c:165
but task is already holding lock:
(&pipe->mutex/1){+.+.}, at: [<00000000a1ed7d17>] pipe_lock_nested fs/pipe.c:67 [inline]
(&pipe->mutex/1){+.+.}, at: [<00000000a1ed7d17>] pipe_lock+0x58/0x70 fs/pipe.c:75
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&pipe->mutex/1){+.+.}:
-> #1 (&sig->cred_guard_mutex){+.+.}:
-> #0 (&p->lock){+.+.}:
other info that might help us debug this:
Chain exists of:
&p->lock --> &sig->cred_guard_mutex --> &pipe->mutex/1
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&pipe->mutex/1);
lock(&sig->cred_guard_mutex);
lock(&pipe->mutex/1);
lock(&p->lock);
*** DEADLOCK ***
1 lock held by syz-executor.4/3972:
#0: (&pipe->mutex/1){+.+.}, at: [<00000000a1ed7d17>] pipe_lock_nested fs/pipe.c:67 [inline]
#0: (&pipe->mutex/1){+.+.}, at: [<00000000a1ed7d17>] pipe_lock+0x58/0x70 fs/pipe.c:75
stack backtrace:
CPU: 1 PID: 3972 Comm: syz-executor.4 Not tainted 4.14.109+ #46
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
kauditd_printk_skb: 168 callbacks suppressed
audit: type=1400 audit(1554261447.259:60525): avc: denied { map } for pid=4041 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(1554261447.459:60526): avc: denied { map } for pid=4050 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(1554261447.459:60527): avc: denied { map } for pid=4050 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(1554261447.459:60528): avc: denied { map } for pid=4050 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(1554261447.459:60529): avc: denied { map } for pid=4050 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(1554261447.489:60530): avc: denied { map } for pid=4050 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(1554261447.509:60531): avc: denied { map } for pid=4050 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(1554261447.509:60532): avc: denied { map } for pid=4050 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(1554261447.519:60533): avc: denied { map } for pid=4050 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(1554261447.529:60534): avc: denied { create } for pid=4048 comm="syz-executor.1" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
kauditd_printk_skb: 354 callbacks suppressed
audit: type=1400 audit(1554261452.319:60889): avc: denied { create } for pid=4175 comm="syz-executor.1" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1554261452.319:60890): avc: denied { write } for pid=4175 comm="syz-executor.1" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
audit: type=1400 audit(1554261452.329:60891): avc: denied { map } for pid=4183 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(1554261452.339:60892): avc: denied { map } for pid=4183 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(1554261452.339:60893): avc: denied { map } for pid=4183 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(1554261452.339:60894): avc: denied { map } for pid=4183 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: audit_backlog=65 > audit_backlog_limit=64
audit: audit_backlog=65 > audit_backlog_limit=64
audit: audit_lost=995 audit_rate_limit=0 audit_backlog_limit=64
audit: type=1400 audit(1554261452.349:60895): avc: denied { map } for pid=4183 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