====================================================== WARNING: possible circular locking dependency detected 4.14.153+ #0 Not tainted ------------------------------------------------------ syz-executor.4/20972 is trying to acquire lock: (&mm->mmap_sem){++++}, at: [<00000000b92fe410>] __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: [<000000003c289615>] inode_lock include/linux/fs.h:724 [inline] (&sb->s_type->i_mutex_key#10){+.+.}, at: [<000000003c289615>] generic_file_write_iter+0x99/0x650 mm/filemap.c:3282 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:2220 [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:3122 __generic_file_write_iter+0x32e/0x550 mm/filemap.c:3257 generic_file_write_iter+0x36f/0x650 mm/filemap.c:3285 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.4/20972: #0: (sb_writers#6){.+.+}, at: [<000000005473924f>] file_start_write include/linux/fs.h:2746 [inline] #0: (sb_writers#6){.+.+}, at: [<000000005473924f>] vfs_write+0x3d8/0x4d0 fs/read_write.c:545 #1: (&sb->s_type->i_mutex_key#10){+.+.}, at: [<000000003c289615>] inode_lock include/linux/fs.h:724 [inline] #1: (&sb->s_type->i_mutex_key#10){+.+.}, at: [<000000003c289615>] generic_file_write_iter+0x99/0x650 mm/filemap.c:3282 stack backtrace: CPU: 0 PID: 20972 Comm: syz-executor.4 Not tainted 4.14.153+ #0 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xca/0x134 lib/dump_stack.c:53 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:ffff888193ef7a90 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 000000000000007f RCX: 0000000000040000 RDX: ffffffff81bac586 RSI: ffffc9000d5a1000 RDI: ffff888193ef7d20 RBP: 1ffff110327def53 R08: 0000000000001000 R09: fffff94000c21a44 R10: fffff94000c21a43 R11: ffffea000610d21f R12: 0000000000001000 R13: 0000000000000000 R14: 000000002014633f R15: ffff888193ef7d18 generic_perform_write+0x158/0x460 mm/filemap.c:3122 __generic_file_write_iter+0x32e/0x550 mm/filemap.c:3257 generic_file_write_iter+0x36f/0x650 mm/filemap.c:3285 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: 0033:0x414017 RSP: 002b:00007f1207d1ba80 EFLAGS: 00000293 ORIG_RAX: 0000000000000012 RAX: ffffffffffffffda RBX: 00000000200013d0 RCX: 0000000000414017 RDX: 0000000008100000 RSI: 0000000020001340 RDI: 0000000000000005 RBP: 00000000000000c8 R08: fe03f80fe03f80ff R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000005 R13: 00000000004c9a8e R14: 00000000004e1788 R15: 00000000ffffffff ================================================================== BUG: KASAN: use-after-free in xfrm6_tunnel_free_spi net/ipv6/xfrm6_tunnel.c:208 [inline] BUG: KASAN: use-after-free in xfrm6_tunnel_destroy+0x4e0/0x560 net/ipv6/xfrm6_tunnel.c:303 Read of size 8 at addr ffff8881c63aa1b8 by task kworker/1:1/68 CPU: 1 PID: 68 Comm: kworker/1:1 Not tainted 4.14.153+ #0 Workqueue: events xfrm_state_gc_task Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xca/0x134 lib/dump_stack.c:53 print_address_description+0x60/0x226 mm/kasan/report.c:187 __kasan_report.cold+0x1a/0x41 mm/kasan/report.c:316 xfrm6_tunnel_free_spi net/ipv6/xfrm6_tunnel.c:208 [inline] xfrm6_tunnel_destroy+0x4e0/0x560 net/ipv6/xfrm6_tunnel.c:303 xfrm_state_gc_destroy net/xfrm/xfrm_state.c:449 [inline] xfrm_state_gc_task+0x3d6/0x550 net/xfrm/xfrm_state.c:470 process_one_work+0x7f1/0x1580 kernel/workqueue.c:2134 worker_thread+0xdd/0xdf0 kernel/workqueue.c:2271 kthread+0x31f/0x430 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:404 Allocated by task 19665: save_stack mm/kasan/common.c:76 [inline] set_track mm/kasan/common.c:85 [inline] __kasan_kmalloc.part.0+0x53/0xc0 mm/kasan/common.c:501 kmalloc include/linux/slab.h:493 [inline] kzalloc include/linux/slab.h:661 [inline] ops_init+0xee/0x3f0 net/core/net_namespace.c:108 setup_net+0x259/0x550 net/core/net_namespace.c:295 copy_net_ns+0x195/0x480 net/core/net_namespace.c:419 create_new_namespaces+0x373/0x760 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xa5/0x1e0 kernel/nsproxy.c:206 SYSC_unshare kernel/fork.c:2543 [inline] SyS_unshare+0x34e/0x6c0 kernel/fork.c:2493 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 0xffffffffffffffff Freed by task 7519: save_stack mm/kasan/common.c:76 [inline] set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x164/0x210 mm/kasan/common.c:463 slab_free_hook mm/slub.c:1407 [inline] slab_free_freelist_hook mm/slub.c:1458 [inline] slab_free mm/slub.c:3039 [inline] kfree+0x108/0x3a0 mm/slub.c:3976 ops_free net/core/net_namespace.c:132 [inline] ops_free_list.part.0+0x1f9/0x330 net/core/net_namespace.c:154 ops_free_list net/core/net_namespace.c:152 [inline] cleanup_net+0x466/0x870 net/core/net_namespace.c:488 process_one_work+0x7f1/0x1580 kernel/workqueue.c:2134 worker_thread+0xdd/0xdf0 kernel/workqueue.c:2271 kthread+0x31f/0x430 kernel/kthread.c:232 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:404 0xffffffffffffffff The buggy address belongs to the object at ffff8881c63aa100 which belongs to the cache kmalloc-8192 of size 8192 The buggy address is located 184 bytes inside of 8192-byte region [ffff8881c63aa100, ffff8881c63ac100) The buggy address belongs to the page: page:ffffea000718ea00 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 0000000000000000 0000000000000000 0000000100030003 raw: 0000000000000000 0000000100000001 ffff8881da802400 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881c63aa080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881c63aa100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881c63aa180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881c63aa200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881c63aa280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================