XFS (loop4): Invalid superblock magic number
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BUG: KASAN: use-after-free in route4_get+0x2e6/0x320 net/sched/cls_route.c:242
Read of size 4 at addr ffff88809cbf2240 by task syz-executor.4/9592

CPU: 1 PID: 9592 Comm: syz-executor.4 Not tainted 4.14.173-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x13e/0x194 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393
 route4_get+0x2e6/0x320 net/sched/cls_route.c:242
 tc_ctl_tfilter+0xc04/0x18e6 net/sched/cls_api.c:689
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4315
 netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xc5/0x100 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c849
RSP: 002b:00007f3b8cbf5c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3b8cbf66d4 RCX: 000000000045c849
RDX: 0000000000000000 RSI: 0000000020000280 RDI: 000000000000000c
RBP: 000000000076bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009f9 R14: 00000000004ccb11 R15: 000000000076bfac

Allocated by task 9581:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529
 kmem_cache_alloc_trace+0x14d/0x7b0 mm/slab.c:3618
 kmalloc include/linux/slab.h:488 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 route4_change+0x215/0x1c4d net/sched/cls_route.c:498
 tc_ctl_tfilter+0xf13/0x18e6 net/sched/cls_api.c:738
 rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4315
 netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2433
 netlink_unicast_kernel net/netlink/af_netlink.c:1287 [inline]
 netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1313
 netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1878
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xc5/0x100 net/socket.c:656
 ___sys_sendmsg+0x70a/0x840 net/socket.c:2062
 __sys_sendmsg+0xa3/0x120 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 2392:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 route4_delete_filter_work+0x17/0x20 net/sched/cls_route.c:272
 process_one_work+0x813/0x1540 kernel/workqueue.c:2114
 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2248
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

The buggy address belongs to the object at ffff88809cbf2200
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 64 bytes inside of
 192-byte region [ffff88809cbf2200, ffff88809cbf22c0)
The buggy address belongs to the page:
page:ffffea000272fc80 count:1 mapcount:0 mapping:ffff88809cbf2000 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff88809cbf2000 0000000000000000 0000000100000010
raw: ffffea000282fce0 ffffea00026ef1a0 ffff88812fe56040 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809cbf2100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809cbf2180: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff88809cbf2200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff88809cbf2280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88809cbf2300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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