====================================================== [ INFO: possible circular locking dependency detected ] 4.9.194+ #0 Not tainted ------------------------------------------------------- syz-executor.4/2687 is trying to acquire lock: (&sig->cred_guard_mutex){+.+.+.}, at: [<000000009cb348d7>] mm_access+0x4f/0x140 kernel/fork.c:1030 but task is already holding lock: (&sb->s_type->i_mutex_key){++++++}, at: [<0000000011782db3>] inode_lock_shared include/linux/fs.h:781 [inline] (&sb->s_type->i_mutex_key){++++++}, at: [<0000000011782db3>] lookup_slow+0x160/0x480 fs/namei.c:1770 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sb->s_type->i_mutex_key){++++++}: lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3756 down_read+0x44/0xb0 kernel/locking/rwsem.c:22 inode_lock_shared include/linux/fs.h:781 [inline] do_last fs/namei.c:3439 [inline] path_openat+0x16a8/0x2f60 fs/namei.c:3665 do_filp_open+0x1a1/0x280 fs/namei.c:3699 do_open_execat+0x10c/0x6a0 fs/exec.c:844 open_exec+0x37/0x70 fs/exec.c:876 load_script+0x572/0x710 fs/binfmt_script.c:100 search_binary_handler fs/exec.c:1621 [inline] search_binary_handler+0x14f/0x700 fs/exec.c:1599 exec_binprm fs/exec.c:1663 [inline] do_execveat_common.isra.0+0xf81/0x1db0 fs/exec.c:1785 do_execveat fs/exec.c:1840 [inline] SYSC_execveat fs/exec.c:1921 [inline] SyS_execveat+0x55/0x70 fs/exec.c:1913 do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 entry_SYSCALL_64_after_swapgs+0x5d/0xdb -> #0 (&sig->cred_guard_mutex){+.+.+.}: 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+0x2d22/0x4390 kernel/locking/lockdep.c:3345 lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3756 __mutex_lock_common kernel/locking/mutex.c:521 [inline] mutex_lock_killable_nested+0xcd/0xa10 kernel/locking/mutex.c:641 mm_access+0x4f/0x140 kernel/fork.c:1030 map_files_d_revalidate+0xfa/0x6d0 fs/proc/base.c:1929 d_revalidate fs/namei.c:792 [inline] lookup_slow+0x373/0x480 fs/namei.c:1781 walk_component+0x71e/0xce0 fs/namei.c:1909 lookup_last fs/namei.c:2391 [inline] path_lookupat.isra.0+0x18f/0x3f0 fs/namei.c:2408 filename_lookup+0x1a1/0x3b0 fs/namei.c:2442 user_path_at_empty+0x43/0x50 fs/namei.c:2703 user_path_at include/linux/namei.h:55 [inline] SYSC_quotactl fs/quota/quota.c:862 [inline] SyS_quotactl+0x623/0x1170 fs/quota/quota.c:834 do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 entry_SYSCALL_64_after_swapgs+0x5d/0xdb other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key); lock(&sig->cred_guard_mutex); lock(&sb->s_type->i_mutex_key); lock(&sig->cred_guard_mutex); *** DEADLOCK *** 1 lock held by syz-executor.4/2687: #0: (&sb->s_type->i_mutex_key){++++++}, at: [<0000000011782db3>] inode_lock_shared include/linux/fs.h:781 [inline] #0: (&sb->s_type->i_mutex_key){++++++}, at: [<0000000011782db3>] lookup_slow+0x160/0x480 fs/namei.c:1770 stack backtrace: CPU: 0 PID: 2687 Comm: syz-executor.4 Not tainted 4.9.194+ #0 ffff8801a22073f8 ffffffff81b67001 ffffffff83cb0480 ffffffff83c80ed0 ffffffff83cb0480 ffffffff84252000 ffff8801a658df00 ffff8801a2207450 ffffffff81406d83 0000000000000050 ffff8801a2207540 ffff8801a658e7d8 Call Trace: [<00000000f62ab783>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000f62ab783>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<00000000b38b0321>] print_circular_bug.cold+0x2f6/0x454 kernel/locking/lockdep.c:1202 [<0000000049487153>] check_prev_add kernel/locking/lockdep.c:1828 [inline] [<0000000049487153>] check_prevs_add kernel/locking/lockdep.c:1938 [inline] [<0000000049487153>] validate_chain kernel/locking/lockdep.c:2265 [inline] [<0000000049487153>] __lock_acquire+0x2d22/0x4390 kernel/locking/lockdep.c:3345 [<0000000084e3a846>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3756 [<000000008769934b>] __mutex_lock_common kernel/locking/mutex.c:521 [inline] [<000000008769934b>] mutex_lock_killable_nested+0xcd/0xa10 kernel/locking/mutex.c:641 [<000000009cb348d7>] mm_access+0x4f/0x140 kernel/fork.c:1030 [<00000000ea8afdbc>] map_files_d_revalidate+0xfa/0x6d0 fs/proc/base.c:1929 [<0000000003ac7c99>] d_revalidate fs/namei.c:792 [inline] [<0000000003ac7c99>] lookup_slow+0x373/0x480 fs/namei.c:1781 [<00000000a9a58107>] walk_component+0x71e/0xce0 fs/namei.c:1909 [<00000000c6da53cc>] lookup_last fs/namei.c:2391 [inline] [<00000000c6da53cc>] path_lookupat.isra.0+0x18f/0x3f0 fs/namei.c:2408 [<00000000034da359>] filename_lookup+0x1a1/0x3b0 fs/namei.c:2442 [<000000002b0b669b>] user_path_at_empty+0x43/0x50 fs/namei.c:2703 [<00000000261f7758>] user_path_at include/linux/namei.h:55 [inline] [<00000000261f7758>] SYSC_quotactl fs/quota/quota.c:862 [inline] [<00000000261f7758>] SyS_quotactl+0x623/0x1170 fs/quota/quota.c:834 [<00000000f5ed5afc>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<000000006df35b18>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=2669 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=2669 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=2669 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=2669 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=2669 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=2669 comm=syz-executor.0 audit: type=1400 audit(2000000062.090:3590): avc: denied { create } for pid=2740 comm="syz-executor.4" 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(2000000062.310:3591): avc: denied { write } for pid=2740 comm="syz-executor.4" 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(2000000062.630:3592): avc: denied { read } for pid=2740 comm="syz-executor.4" 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(2000000062.740:3593): avc: denied { create } for pid=2740 comm="syz-executor.4" 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 devpts: called with bogus options audit: type=1400 audit(2000000068.310:3594): avc: denied { create } for pid=2952 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(2000000068.420:3595): avc: denied { write } for pid=2952 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(2000000068.690:3596): avc: denied { read } for pid=2952 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(2000000068.970:3597): avc: denied { create } for pid=2952 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(2000000069.040:3598): avc: denied { write } for pid=2952 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(2000000069.480:3599): avc: denied { create } for pid=2999 comm="syz-executor.4" 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(2000000069.990:3600): avc: denied { create } for pid=3035 comm="syz-executor.4" 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(2000000070.020:3601): avc: denied { write } for pid=3035 comm="syz-executor.4" 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(2000000070.090:3602): avc: denied { read } for pid=3035 comm="syz-executor.4" 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