[ INFO: possible circular locking dependency detected ] 4.9.202+ #0 Not tainted ------------------------------------------------------- syz-executor.5/6173 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<0000000081a8a257>] __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: [<00000000b3148349>] inode_lock include/linux/fs.h:771 [inline] (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<00000000b3148349>] 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: -> #2 (&sb->s_type->i_mutex_key#10){+.+.+.}: 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 -> #1 (ashmem_mutex){+.+.+.}: 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 -> #0 (&mm->mmap_sem){++++++}: 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: &mm->mmap_sem --> ashmem_mutex --> &sb->s_type->i_mutex_key#10 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.5/6173: #0: (sb_writers#6){.+.+.+}, at: [<000000004551f5ec>] file_start_write include/linux/fs.h:2645 [inline] #0: (sb_writers#6){.+.+.+}, at: [<000000004551f5ec>] vfs_write+0x3e9/0x520 fs/read_write.c:558 #1: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<00000000b3148349>] inode_lock include/linux/fs.h:771 [inline] #1: (&sb->s_type->i_mutex_key#10){+.+.+.}, at: [<00000000b3148349>] generic_file_write_iter+0x9a/0x630 mm/filemap.c:3090 stack backtrace: CPU: 1 PID: 6173 Comm: syz-executor.5 Not tainted 4.9.202+ #0 ffff8801a75175d8 ffffffff81b55d2b ffffffff83caeee0 ffffffff83cb7e50 ffffffff83cf5470 ffffffff8424ff40 ffff88019e425f00 ffff8801a7517630 ffffffff81406d6a dffffc0000000000 ffffffff840ab7c0 ffff88019e426800 Call Trace: [<000000007efec0f9>] __dump_stack lib/dump_stack.c:15 [inline] [<000000007efec0f9>] dump_stack+0xcb/0x130 lib/dump_stack.c:56 [<000000003344950e>] print_circular_bug.cold+0x2f6/0x454 kernel/locking/lockdep.c:1202 [<0000000095bbb9f2>] check_prev_add kernel/locking/lockdep.c:1828 [inline] [<0000000095bbb9f2>] check_prevs_add kernel/locking/lockdep.c:1938 [inline] [<0000000095bbb9f2>] validate_chain kernel/locking/lockdep.c:2265 [inline] [<0000000095bbb9f2>] __lock_acquire+0x2d22/0x4390 kernel/locking/lockdep.c:3345 [<000000008f39743f>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 [<00000000d6bcb798>] down_read+0x44/0xb0 kernel/locking/rwsem.c:22 [<0000000081a8a257>] __do_page_fault+0x7bd/0xa60 arch/x86/mm/fault.c:1337 [<000000003101f0cb>] do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1464 [<000000002ca4b308>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:956 [<000000001dfc93de>] generic_perform_write+0x1b6/0x500 mm/filemap.c:2930 [<000000008993a02d>] __generic_file_write_iter+0x340/0x530 mm/filemap.c:3065 [<000000009fa9ba4e>] generic_file_write_iter+0x38a/0x630 mm/filemap.c:3093 [<00000000679918a1>] new_sync_write fs/read_write.c:498 [inline] [<00000000679918a1>] __vfs_write+0x3c1/0x560 fs/read_write.c:511 [<00000000980443fc>] vfs_write+0x185/0x520 fs/read_write.c:559 [<000000007aa0bfa7>] SYSC_write fs/read_write.c:607 [inline] [<000000007aa0bfa7>] SyS_write+0x121/0x270 fs/read_write.c:599 [<00000000387e957e>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<00000000b17f3060>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb blk_update_request: I/O error, dev loop10, sector 2 EXT4-fs (loop10): unable to read superblock blk_update_request: I/O error, dev loop10, sector 2 EXT4-fs (loop10): unable to read superblock netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'. netlink: 24 bytes leftover after parsing attributes in process `syz-executor.3'. input: syz1 as /devices/virtual/input/input47 input: syz1 as /devices/virtual/input/input48 uinput: write device info first input: syz1 as /devices/virtual/input/input51 selinux_nlmsg_perm: 23 callbacks suppressed SELinux: unrecognized netlink message: protocol=6 nlmsg_type=29231 sclass=netlink_xfrm_socket pig=6302 comm=syz-executor.5 input: syz1 as /devices/virtual/input/input52 audit_printk_skb: 45 callbacks suppressed audit: type=1400 audit(1574625872.560:2311): avc: denied { wake_alarm } for pid=6317 comm="syz-executor.2" capability=35 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=capability2 permissive=1 audit: type=1400 audit(1574625872.630:2312): avc: denied { block_suspend } for pid=6317 comm="syz-executor.2" capability=36 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=capability2 permissive=1 audit: type=1400 audit(1574625873.330:2313): avc: denied { wake_alarm } for pid=6317 comm="syz-executor.2" capability=35 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=capability2 permissive=1 audit: type=1400 audit(1574625873.370:2314): avc: denied { block_suspend } for pid=6317 comm="syz-executor.2" capability=36 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=capability2 permissive=1 audit: type=1400 audit(1574625874.510:2315): avc: denied { set_context_mgr } for pid=6404 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=binder permissive=1 audit: type=1400 audit(1574625874.660:2316): avc: denied { set_context_mgr } for pid=6404 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=binder permissive=1 input: syz1 as /devices/virtual/input/input53 audit: type=1400 audit(1574625875.110:2317): avc: denied { wake_alarm } for pid=6434 comm="syz-executor.2" capability=35 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=capability2 permissive=1 audit: type=1400 audit(1574625875.360:2318): avc: denied { wake_alarm } for pid=6434 comm="syz-executor.2" capability=35 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=capability2 permissive=1 audit: type=1400 audit(1574625875.540:2319): avc: denied { map_create } for pid=6456 comm="syz-executor.3" 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 audit: type=1400 audit(1574625875.590:2320): avc: denied { map_create } for pid=6456 comm="syz-executor.3" 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 input: syz1 as /devices/virtual/input/input55 input: syz1 as /devices/virtual/input/input56 audit_printk_skb: 21 callbacks suppressed audit: type=1400 audit(1574625878.380:2328): avc: denied { prog_load } for pid=6584 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=bpf permissive=1 audit: type=1400 audit(1574625878.630:2329): avc: denied { prog_run } for pid=6584 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=bpf permissive=1 audit: type=1400 audit(1574625878.820:2330): avc: denied { prog_load } for pid=6584 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=bpf permissive=1