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BUG: KASAN: use-after-free in rfcomm_dlc_get net/bluetooth/rfcomm/core.c:360 [inline]
BUG: KASAN: use-after-free in __rfcomm_dlc_open net/bluetooth/rfcomm/core.c:396 [inline]
BUG: KASAN: use-after-free in rfcomm_dlc_open+0xc85/0xd60 net/bluetooth/rfcomm/core.c:431
Read of size 1 at addr ffff88808ab26444 by task syz-executor.3/31977

CPU: 0 PID: 31977 Comm: syz-executor.3 Not tainted 5.1.0+ #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188
 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/generic_report.c:129
 rfcomm_dlc_get net/bluetooth/rfcomm/core.c:360 [inline]
 __rfcomm_dlc_open net/bluetooth/rfcomm/core.c:396 [inline]
 rfcomm_dlc_open+0xc85/0xd60 net/bluetooth/rfcomm/core.c:431
 rfcomm_sock_connect+0x38a/0x4b0 net/bluetooth/rfcomm/sock.c:416
 __sys_connect+0x266/0x330 net/socket.c:1840
 __do_sys_connect net/socket.c:1851 [inline]
 __se_sys_connect net/socket.c:1848 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:1848
 do_syscall_64+0x103/0x670 arch/x86/entry/common.c:298
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458da9
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fcd915afc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458da9
RDX: 000000000000000e RSI: 0000000020000080 RDI: 0000000000000004
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fcd915b06d4
R13: 00000000004bf197 R14: 00000000004d0410 R15: 00000000ffffffff

Allocated by task 29670:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc mm/kasan/common.c:489 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503
 __do_kmalloc_node mm/slab.c:3651 [inline]
 __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3665
 __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:142
 __alloc_skb+0x10b/0x5e0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1058 [inline]
 nlmsg_new include/net/netlink.h:885 [inline]
 __neigh_notify+0x8b/0x160 net/core/neighbour.c:3347
 neigh_update_notify net/core/neighbour.c:2518 [inline]
 neigh_timer_handler+0x5d5/0xf30 net/core/neighbour.c:1102
 call_timer_fn+0x196/0x720 kernel/time/timer.c:1322
 expire_timers kernel/time/timer.c:1366 [inline]
 __run_timers kernel/time/timer.c:1685 [inline]
 __run_timers kernel/time/timer.c:1653 [inline]
 run_timer_softirq+0x66f/0x1740 kernel/time/timer.c:1698
 __do_softirq+0x266/0x95a kernel/softirq.c:293

Freed by task 29670:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
 __cache_free mm/slab.c:3463 [inline]
 kfree+0xcf/0x230 mm/slab.c:3786
 skb_free_head+0x93/0xb0 net/core/skbuff.c:592
 skb_release_data+0x576/0x7a0 net/core/skbuff.c:612
 skb_release_all+0x4d/0x60 net/core/skbuff.c:666
 __kfree_skb net/core/skbuff.c:680 [inline]
 consume_skb net/core/skbuff.c:740 [inline]
 consume_skb+0xe2/0x380 net/core/skbuff.c:734
 netlink_broadcast_filtered+0x316/0xb20 net/netlink/af_netlink.c:1521
 netlink_broadcast net/netlink/af_netlink.c:1543 [inline]
 nlmsg_multicast include/net/netlink.h:965 [inline]
 nlmsg_notify+0x93/0x1c0 net/netlink/af_netlink.c:2529
 rtnl_notify+0xc5/0xf0 net/core/rtnetlink.c:741
 __neigh_notify+0xe3/0x160 net/core/neighbour.c:3358
 neigh_update_notify net/core/neighbour.c:2518 [inline]
 neigh_timer_handler+0x5d5/0xf30 net/core/neighbour.c:1102
 call_timer_fn+0x196/0x720 kernel/time/timer.c:1322
 expire_timers kernel/time/timer.c:1366 [inline]
 __run_timers kernel/time/timer.c:1685 [inline]
 __run_timers kernel/time/timer.c:1653 [inline]
 run_timer_softirq+0x66f/0x1740 kernel/time/timer.c:1698
 __do_softirq+0x266/0x95a kernel/softirq.c:293

The buggy address belongs to the object at ffff88808ab26300
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 324 bytes inside of
 512-byte region [ffff88808ab26300, ffff88808ab26500)
The buggy address belongs to the page:
page:ffffea00022ac980 count:1 mapcount:0 mapping:ffff8880aa400940 index:0xffff88808ab26d00
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea0002481748 ffffea000290a6c8 ffff8880aa400940
raw: ffff88808ab26d00 ffff88808ab26080 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808ab26300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808ab26380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808ab26400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff88808ab26480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808ab26500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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