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BUG: KASAN: use-after-free in ex_handler_refcount+0x164/0x1a0 arch/x86/mm/extable.c:49
Write of size 4 at addr ffff8880951c8500 by task kworker/u4:5/7502

CPU: 1 PID: 7502 Comm: kworker/u4:5 Not tainted 4.14.184-syzkaller #0
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'.
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: tipc_rcv tipc_recv_work
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1dc 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+0xa9/0x2b9 mm/kasan/report.c:393
 ex_handler_refcount+0x164/0x1a0 arch/x86/mm/extable.c:49
 fixup_exception+0x8a/0xc3 arch/x86/mm/extable.c:197
 do_trap_no_signal arch/x86/kernel/traps.c:208 [inline]
 do_trap+0x61/0x250 arch/x86/kernel/traps.c:257
 do_error_trap+0x132/0x2d0 arch/x86/kernel/traps.c:301
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964
RIP: 0010:inat_get_avx_attribute+0x60b2/0x6b25
RSP: 0018:ffff88806744fb78 EFLAGS: 00010287
RAX: ffff88806743a3c0 RBX: ffff8880951c8500 RCX: ffff8880951c8500
RDX: 0000000000000000 RSI: 1ffff1100ce89f62 RDI: ffff8880951c8500
RBP: ffff88809f072e18 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880951c8500
R13: ffff8880951c8508 R14: 0000000000000000 R15: ffff88809f072e00
 tipc_subscrp_subscribe net/tipc/subscr.c:303 [inline]
 tipc_subscrb_rcv_cb+0x5e7/0xa40 net/tipc/subscr.c:338
 tipc_receive_from_sock+0x26a/0x460 net/tipc/server.c:273
 tipc_recv_work+0x79/0xe0 net/tipc/server.c:547
 process_one_work+0x7c0/0x14c0 kernel/workqueue.c:2116
 worker_thread+0x5d7/0x1080 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Allocated by task 2322:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.0+0x4f/0xd0 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x14d/0x3f0 mm/slab.c:3618
 kmalloc include/linux/slab.h:488 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 tipc_subscrb_create net/tipc/subscr.c:223 [inline]
 tipc_subscrb_connect_cb+0x40/0x150 net/tipc/subscr.c:344
 tipc_accept_from_sock+0x25b/0x400 net/tipc/server.c:313
 tipc_recv_work+0x79/0xe0 net/tipc/server.c:547
 process_one_work+0x7c0/0x14c0 kernel/workqueue.c:2116
 worker_thread+0x5d7/0x1080 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Freed by task 2322:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xaf/0x190 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 tipc_subscrb_kref_release net/tipc/subscr.c:155 [inline]
 kref_put include/linux/kref.h:70 [inline]
 tipc_subscrb_put+0x22/0x30 net/tipc/subscr.c:160
 tipc_close_conn+0x16a/0x200 net/tipc/server.c:203
 tipc_send_to_sock net/tipc/server.c:538 [inline]
 tipc_send_work+0x41a/0x520 net/tipc/server.c:564
 process_one_work+0x7c0/0x14c0 kernel/workqueue.c:2116
 worker_thread+0x5d7/0x1080 kernel/workqueue.c:2250
 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 ffff8880951c8500
 which belongs to the cache kmalloc-96 of size 96
The buggy address is located 0 bytes inside of
 96-byte region [ffff8880951c8500, ffff8880951c8560)
The buggy address belongs to the page:
page:ffffea0002547200 count:1 mapcount:0 mapping:ffff8880951c8000 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffff8880951c8000 0000000000000000 0000000100000020
raw: ffffea0002802ca0 ffffea000281b1a0 ffff8880aa8004c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880951c8400: 00 00 00 00 00 00 00 00 04 fc fc fc fc fc fc fc
 ffff8880951c8480: 00 00 00 00 00 00 00 00 02 fc fc fc fc fc fc fc
>ffff8880951c8500: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                   ^
 ffff8880951c8580: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff8880951c8600: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
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