====================================================== [ INFO: possible circular locking dependency detected ] 4.9.202+ #0 Not tainted ------------------------------------------------------- syz-executor.2/6657 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<00000000995dd80f>] __do_page_fault+0x7bd/0xa60 arch/x86/mm/fault.c:1337 but task is already holding lock: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<00000000d1496ba3>] inode_lock include/linux/fs.h:771 [inline] (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<00000000d1496ba3>] generic_file_write_iter+0x9a/0x630 mm/filemap.c:3090 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 down_write+0x41/0xa0 kernel/locking/rwsem.c:52 inode_lock include/linux/fs.h:771 [inline] shmem_fallocate+0x143/0xab0 mm/shmem.c:2683 ashmem_shrink_scan drivers/staging/android/ashmem.c:462 [inline] ashmem_shrink_scan+0x1c3/0x4c0 drivers/staging/android/ashmem.c:446 ashmem_ioctl+0x29b/0xdd0 drivers/staging/android/ashmem.c:804 vfs_ioctl fs/ioctl.c:43 [inline] file_ioctl fs/ioctl.c:493 [inline] do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677 SYSC_ioctl fs/ioctl.c:694 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685 do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 entry_SYSCALL_64_after_swapgs+0x5d/0xdb lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 __mutex_lock_common kernel/locking/mutex.c:521 [inline] mutex_lock_nested+0xc7/0x920 kernel/locking/mutex.c:621 ashmem_mmap+0x53/0x470 drivers/staging/android/ashmem.c:378 mmap_region+0x7e7/0xfa0 mm/mmap.c:1726 do_mmap+0x539/0xbc0 mm/mmap.c:1505 do_mmap_pgoff include/linux/mm.h:2066 [inline] vm_mmap_pgoff+0x179/0x1c0 mm/util.c:329 SYSC_mmap_pgoff mm/mmap.c:1555 [inline] SyS_mmap_pgoff+0xfa/0x1b0 mm/mmap.c:1513 SYSC_mmap arch/x86/kernel/sys_x86_64.c:96 [inline] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:87 do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 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+0x2d22/0x4390 kernel/locking/lockdep.c:3345 lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 down_read+0x44/0xb0 kernel/locking/rwsem.c:22 __do_page_fault+0x7bd/0xa60 arch/x86/mm/fault.c:1337 do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1464 page_fault+0x25/0x30 arch/x86/entry/entry_64.S:956 generic_perform_write+0x1b6/0x500 mm/filemap.c:2930 __generic_file_write_iter+0x340/0x530 mm/filemap.c:3065 generic_file_write_iter+0x38a/0x630 mm/filemap.c:3093 new_sync_write fs/read_write.c:498 [inline] __vfs_write+0x3c1/0x560 fs/read_write.c:511 vfs_write+0x185/0x520 fs/read_write.c:559 SYSC_write fs/read_write.c:607 [inline] SyS_write+0x121/0x270 fs/read_write.c:599 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: Chain exists of: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#10); lock(ashmem_mutex); lock(&sb->s_type->i_mutex_key#10); lock(&mm->mmap_sem); *** DEADLOCK *** 2 locks held by syz-executor.2/6657: #0: (sb_writers#6){.+.+.+}, at: [<000000002fdd5c05>] file_start_write include/linux/fs.h:2645 [inline] #0: (sb_writers#6){.+.+.+}, at: [<000000002fdd5c05>] vfs_write+0x3e9/0x520 fs/read_write.c:558 #1: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<00000000d1496ba3>] inode_lock include/linux/fs.h:771 [inline] #1: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<00000000d1496ba3>] generic_file_write_iter+0x9a/0x630 mm/filemap.c:3090 stack backtrace: CPU: 1 PID: 6657 Comm: syz-executor.2 Not tainted 4.9.202+ #0 ffff8801c67675d8 ffffffff81b55d2b ffffffff83caeb80 ffffffff83cb81b0 ffffffff83ce1df0 ffffffff8424ff40 ffff8801d9bf97c0 ffff8801c6767630 ffffffff81406d6a dffffc0000000000 ffffffff84043fc0 ffff8801d9bfa0c0 Call Trace: [<00000000b3df6a7e>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000b3df6a7e>] dump_stack+0xcb/0x130 lib/dump_stack.c:56 [<00000000447bcd54>] print_circular_bug.cold+0x2f6/0x454 kernel/locking/lockdep.c:1202 [<0000000026cbb3ab>] check_prev_add kernel/locking/lockdep.c:1828 [inline] [<0000000026cbb3ab>] check_prevs_add kernel/locking/lockdep.c:1938 [inline] [<0000000026cbb3ab>] validate_chain kernel/locking/lockdep.c:2265 [inline] [<0000000026cbb3ab>] __lock_acquire+0x2d22/0x4390 kernel/locking/lockdep.c:3345 [<000000002ddcf7b2>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 [<00000000a00795c4>] down_read+0x44/0xb0 kernel/locking/rwsem.c:22 [<00000000995dd80f>] __do_page_fault+0x7bd/0xa60 arch/x86/mm/fault.c:1337 [<000000006ceb4969>] do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1464 [<000000006809f8db>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:956 [<00000000fdefcb39>] generic_perform_write+0x1b6/0x500 mm/filemap.c:2930 [<000000007fc006d6>] __generic_file_write_iter+0x340/0x530 mm/filemap.c:3065 [<0000000091d29598>] generic_file_write_iter+0x38a/0x630 mm/filemap.c:3093 [<0000000068daff41>] new_sync_write fs/read_write.c:498 [inline] [<0000000068daff41>] __vfs_write+0x3c1/0x560 fs/read_write.c:511 [<00000000134655d3>] vfs_write+0x185/0x520 fs/read_write.c:559 [<000000007674cba2>] SYSC_write fs/read_write.c:607 [inline] [<000000007674cba2>] SyS_write+0x121/0x270 fs/read_write.c:599 [<00000000f213efba>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<000000007d2cedaf>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb device lo entered promiscuous mode audit: type=1400 audit(1574481854.940:36): avc: denied { create } for pid=6687 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(1574481854.970:37): avc: denied { write } for pid=6687 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(1574481855.030:38): avc: denied { read } for pid=6687 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(1574481855.140:39): avc: denied { prog_load } for pid=6705 comm="syz-executor.2" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=bpf permissive=1 device lo left promiscuous mode audit: type=1400 audit(1574481855.320:40): avc: denied { create } for pid=6683 comm="syz-executor.5" 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(1574481855.350:41): avc: denied { write } for pid=6683 comm="syz-executor.5" 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(1574481855.370:42): avc: denied { read } for pid=6683 comm="syz-executor.5" 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 device lo entered promiscuous mode SELinux: unrecognized netlink message: protocol=0 nlmsg_type=30561 sclass=netlink_route_socket pig=6707 comm=syz-executor.5 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=30561 sclass=netlink_route_socket pig=6716 comm=syz-executor.5 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=30561 sclass=netlink_route_socket pig=6717 comm=syz-executor.5 device lo left promiscuous mode audit: type=1400 audit(1574481855.650:43): avc: denied { create } for pid=6687 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(1574481855.680:44): avc: denied { write } for pid=6687 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(1574481855.710:45): avc: denied { read } for pid=6687 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_printk_skb: 18 callbacks suppressed audit: type=1400 audit(1574481862.760:52): avc: denied { associate } for pid=7022 comm="syz-executor.5" name="syz0" scontext=unconfined_u:object_r:unlabeled_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=filesystem permissive=1 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=7036 comm=syz-executor.0 audit: type=1400 audit(1574481862.820:53): avc: denied { create } for pid=7029 comm="syz-executor.2" 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 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=7036 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=7036 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=7036 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=7036 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=7036 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=7036 comm=syz-executor.0 device lo entered promiscuous mode SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=7036 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=7036 comm=syz-executor.0 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=0 sclass=netlink_route_socket pig=7036 comm=syz-executor.0 audit: type=1400 audit(1574481863.260:54): avc: denied { write } for pid=7029 comm="syz-executor.2" 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(1574481863.290:55): avc: denied { read } for pid=7029 comm="syz-executor.2" 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 device lo left promiscuous mode audit: type=1400 audit(1574481863.540:56): avc: denied { create } for pid=7083 comm="syz-executor.2" 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(1574481863.560:57): avc: denied { write } for pid=7083 comm="syz-executor.2" 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 device lo entered promiscuous mode audit: type=1400 audit(1574481863.650:58): avc: denied { create } for pid=7097 comm="syz-executor.0" 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 input: syz0 as /devices/virtual/input/input10 audit: type=1400 audit(1574481863.720:59): avc: denied { write } for pid=7097 comm="syz-executor.0" 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(1574481863.750:60): avc: denied { read } for pid=7097 comm="syz-executor.0" 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 uinput: write device info first netlink: 7 bytes leftover after parsing attributes in process `syz-executor.0'. input: syz0 as /devices/virtual/input/input12 device lo left promiscuous mode audit: type=1400 audit(1574481863.890:61): avc: denied { create } for pid=7097 comm="syz-executor.0" 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 device lo entered promiscuous mode