====================================================== WARNING: possible circular locking dependency detected 4.14.155-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/14777 is trying to acquire lock: (&mm->mmap_sem){++++}, at: [<000000000f605bf8>] __do_page_fault+0x8a4/0xbb0 arch/x86/mm/fault.c:1356 but task is already holding lock: (&sb->s_type->i_mutex_key#10){+.+.}, at: [<000000009c9437e3>] inode_lock include/linux/fs.h:724 [inline] (&sb->s_type->i_mutex_key#10){+.+.}, at: [<000000009c9437e3>] generic_file_write_iter+0x99/0x650 mm/filemap.c:3283 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sb->s_type->i_mutex_key#10){+.+.}: down_write+0x34/0x90 kernel/locking/rwsem.c:54 inode_lock include/linux/fs.h:724 [inline] shmem_fallocate+0x150/0xae0 mm/shmem.c:2904 ashmem_shrink_scan drivers/staging/android/ashmem.c:453 [inline] ashmem_shrink_scan+0x1ca/0x4f0 drivers/staging/android/ashmem.c:437 ashmem_ioctl+0x2b4/0xd20 drivers/staging/android/ashmem.c:795 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0xabe/0x1040 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #1 (ashmem_mutex){+.+.}: __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0xf7/0x13e0 kernel/locking/mutex.c:893 ashmem_mmap+0x4c/0x450 drivers/staging/android/ashmem.c:369 call_mmap include/linux/fs.h:1803 [inline] mmap_region+0x7d9/0xfb0 mm/mmap.c:1736 do_mmap+0x548/0xb80 mm/mmap.c:1512 do_mmap_pgoff include/linux/mm.h:2215 [inline] vm_mmap_pgoff+0x177/0x1c0 mm/util.c:333 SYSC_mmap_pgoff mm/mmap.c:1564 [inline] SyS_mmap_pgoff+0xf4/0x1b0 mm/mmap.c:1520 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #0 (&mm->mmap_sem){++++}: lock_acquire+0x12b/0x360 kernel/locking/lockdep.c:3994 down_read+0x37/0xa0 kernel/locking/rwsem.c:24 __do_page_fault+0x8a4/0xbb0 arch/x86/mm/fault.c:1356 page_fault+0x22/0x50 arch/x86/entry/entry_64.S:1122 fault_in_pages_readable include/linux/pagemap.h:614 [inline] iov_iter_fault_in_readable+0x29c/0x350 lib/iov_iter.c:421 generic_perform_write+0x158/0x460 mm/filemap.c:3123 __generic_file_write_iter+0x32e/0x550 mm/filemap.c:3258 generic_file_write_iter+0x36f/0x650 mm/filemap.c:3286 call_write_iter include/linux/fs.h:1798 [inline] new_sync_write fs/read_write.c:471 [inline] __vfs_write+0x401/0x5a0 fs/read_write.c:484 vfs_write+0x17f/0x4d0 fs/read_write.c:546 SYSC_pwrite64 fs/read_write.c:636 [inline] SyS_pwrite64+0x136/0x160 fs/read_write.c:623 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 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.0/14777: #0: (sb_writers#6){.+.+}, at: [<00000000097e019e>] file_start_write include/linux/fs.h:2746 [inline] #0: (sb_writers#6){.+.+}, at: [<00000000097e019e>] vfs_write+0x3d8/0x4d0 fs/read_write.c:545 #1: (&sb->s_type->i_mutex_key#10){+.+.}, at: [<000000009c9437e3>] inode_lock include/linux/fs.h:724 [inline] #1: (&sb->s_type->i_mutex_key#10){+.+.}, at: [<000000009c9437e3>] generic_file_write_iter+0x99/0x650 mm/filemap.c:3283 stack backtrace: CPU: 1 PID: 14777 Comm: syz-executor.0 Not tainted 4.14.155-syzkaller #0 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xe5/0x154 lib/dump_stack.c:58 print_circular_bug.isra.0.cold+0x2dc/0x425 kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2f5f/0x4320 kernel/locking/lockdep.c:3487 lock_acquire+0x12b/0x360 kernel/locking/lockdep.c:3994 down_read+0x37/0xa0 kernel/locking/rwsem.c:24 __do_page_fault+0x8a4/0xbb0 arch/x86/mm/fault.c:1356 page_fault+0x22/0x50 arch/x86/entry/entry_64.S:1122 RIP: 0010:fault_in_pages_readable include/linux/pagemap.h:614 [inline] RIP: 0010:iov_iter_fault_in_readable+0x29c/0x350 lib/iov_iter.c:421 RSP: 0018:ffff8881d2a07a90 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00000000000003ff RCX: 0000000000040000 RDX: ffffffff81bad5a6 RSI: ffffc900001d0000 RDI: ffff8881d2a07d20 RBP: 1ffff1103a540f53 R08: 0000000000001000 R09: fffff94000c4f83c R10: fffff94000c4f83b R11: ffffea000627c1df R12: 0000000000001000 R13: 0000000000000000 R14: 00000000204b41ff R15: ffff8881d2a07d18 generic_perform_write+0x158/0x460 mm/filemap.c:3123 __generic_file_write_iter+0x32e/0x550 mm/filemap.c:3258 generic_file_write_iter+0x36f/0x650 mm/filemap.c:3286 call_write_iter include/linux/fs.h:1798 [inline] new_sync_write fs/read_write.c:471 [inline] __vfs_write+0x401/0x5a0 fs/read_write.c:484 vfs_write+0x17f/0x4d0 fs/read_write.c:546 SYSC_pwrite64 fs/read_write.c:636 [inline] SyS_pwrite64+0x136/0x160 fs/read_write.c:623 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x414437 RSP: 002b:00007fac841eea80 EFLAGS: 00000293 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 0000000020001610 RCX: 0000000000414437 RDX: 0000000008100000 RSI: 0000000020000200 RDI: 0000000000000009 RBP: 00000000000000e0 R08: fe03f80fe03f80ff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000009 R13: 00000000004ca07f R14: 00000000004e2010 R15: 00000000ffffffff out of order segment: rcv_next BA788C51 seq BA788F99 - BA789001 out of order segment: rcv_next BA788C51 seq BA789001 - BA789055 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=14773 comm=syz-executor.3 prune_queue: c=ba788b89 out of order segment: rcv_next BA788C51 seq BA789055 - BA7890A9 prune_queue: c=ba788b89 out of order segment: rcv_next BA788D6D seq BA788D75 - BA788D91 prune_queue: c=ba788b89 out of order segment: rcv_next BA788D6D seq BA788DF9 - BA788E61 out of order segment: rcv_next BA788D6D seq BA788E61 - BA788EB5 ofo requeuing : rcv_next BA788D75 seq BA788D75 - BA788E59 ofo requeuing : rcv_next BA788E59 seq BA788DF9 - BA788E61 ofo requeuing : rcv_next BA788E61 seq BA788E61 - BA788EB5 out of order segment: rcv_next BA788F7D seq BA788F85 - BA788F99 prune_queue: c=ba788b89 out of order segment: rcv_next BA788F7D seq BA7890A9 - BA789105 ofo requeuing : rcv_next BA788F85 seq BA788F85 - BA789055 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=14824 comm=syz-executor.3 out of order segment: rcv_next BA789055 seq BA789105 - BA789161 out of order segment: rcv_next BA789055 seq BA789161 - BA7891BD out of order segment: rcv_next BA789055 seq BA7891BD - BA789219 out of order segment: rcv_next BA789055 seq BA789219 - BA789275 out of order segment: rcv_next BA789055 seq BA789275 - BA7892D1 out of order segment: rcv_next BA789055 seq BA7892D1 - BA78932D out of order segment: rcv_next BA789055 seq BA78932D - BA789389 out of order segment: rcv_next BA789055 seq BA789389 - BA7893E5 out of order segment: rcv_next BA789055 seq BA7893E5 - BA789441 out of order segment: rcv_next BA789055 seq BA789441 - BA78949D prune_queue: c=ba788b89 out of order segment: rcv_next BA789055 seq BA78949D - BA7894F9 out of order segment: rcv_next BA789055 seq BA7894F9 - BA789555 out of order segment: rcv_next BA789055 seq BA789555 - BA7895B1 out of order segment: rcv_next BA789055 seq BA7895B1 - BA78960D out of order segment: rcv_next BA789055 seq BA78960D - BA789669 out of order segment: rcv_next BA789055 seq BA789669 - BA7896C5 out of order segment: rcv_next BA789055 seq BA7896C5 - BA789721 out of order segment: rcv_next BA789055 seq BA789721 - BA78977D out of order segment: rcv_next BA789055 seq BA78977D - BA7897D9 out of order segment: rcv_next BA789055 seq BA7897D9 - BA789835 out of order segment: rcv_next BA789055 seq BA789835 - BA789891 out of order segment: rcv_next BA789055 seq BA789891 - BA7898ED out of order segment: rcv_next BA789055 seq BA7898ED - BA789949 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=14850 comm=syz-executor.3 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=14852 comm=syz-executor.4 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=14857 comm=syz-executor.1 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=14885 comm=syz-executor.2 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=14919 comm=syz-executor.3 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=14922 comm=syz-executor.4 selinux_nlmsg_perm: 12 callbacks suppressed SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=15099 comm=syz-executor.1 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=15102 comm=syz-executor.3 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=15104 comm=syz-executor.4 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=15144 comm=syz-executor.3 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=15149 comm=syz-executor.1 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=15163 comm=syz-executor.4 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=15196 comm=syz-executor.1 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=15192 comm=syz-executor.3 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=15198 comm=syz-executor.4 SELinux: unrecognized netlink message: protocol=0 nlmsg_type=7216 sclass=netlink_route_socket pig=15239 comm=syz-executor.1