=====================================================
BUG: KMSAN: use-after-free in skb_unref include/linux/skbuff.h:1011 [inline]
BUG: KMSAN: use-after-free in kfree_skb+0x23c/0x4c0 net/core/skbuff.c:693
CPU: 0 PID: 19844 Comm: syz-executor.0 Not tainted 5.4.0-rc5+ #0
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+0x191/0x1f0 lib/dump_stack.c:113
 kmsan_report+0x128/0x220 mm/kmsan/kmsan_report.c:108
 __msan_warning+0x73/0xe0 mm/kmsan/kmsan_instr.c:245
 skb_unref include/linux/skbuff.h:1011 [inline]
 kfree_skb+0x23c/0x4c0 net/core/skbuff.c:693
 bcsp_close+0x127/0x1e0 drivers/bluetooth/hci_bcsp.c:748
 hci_uart_tty_close+0x385/0x410 drivers/bluetooth/hci_ldisc.c:548
 tty_ldisc_close drivers/tty/tty_ldisc.c:494 [inline]
 tty_ldisc_kill drivers/tty/tty_ldisc.c:642 [inline]
 tty_ldisc_release+0x5dd/0xd50 drivers/tty/tty_ldisc.c:814
 tty_release_struct+0x4f/0x1d0 drivers/tty/tty_io.c:1612
 tty_release+0x1be2/0x1e80 drivers/tty/tty_io.c:1785
 __fput+0x4c9/0xba0 fs/file_table.c:280
 ____fput+0x37/0x40 fs/file_table.c:313
 task_work_run+0x22e/0x2a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:163 [inline]
 prepare_exit_to_usermode+0x39d/0x4d0 arch/x86/entry/common.c:194
 syscall_return_slowpath+0x90/0x610 arch/x86/entry/common.c:274
 do_syscall_64+0xdc/0x160 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x413db1
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:0000000000a6fbf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 000000000000000c RCX: 0000000000413db1
RDX: 0000000000000000 RSI: 0000000000000655 RDI: 000000000000000b
RBP: 0000000000000001 R08: 00000000f4b36658 R09: ffffffffffffffff
R10: 0000000000a6fcd0 R11: 0000000000000293 R12: 000000000075c9a0
R13: 000000000075c9a0 R14: 00000000007613e8 R15: 000000000075bfd4

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:151 [inline]
 kmsan_internal_poison_shadow+0x60/0x120 mm/kmsan/kmsan.c:134
 kmsan_slab_free+0x8d/0xf0 mm/kmsan/kmsan_hooks.c:108
 slab_free_freelist_hook mm/slub.c:1473 [inline]
 slab_free mm/slub.c:3046 [inline]
 kmem_cache_free+0x2d1/0x2b70 mm/slub.c:3062
 kfree_skbmem net/core/skbuff.c:644 [inline]
 __kfree_skb+0x1dd/0x210 net/core/skbuff.c:680
 consume_skb+0x2b0/0x2e0 net/core/skbuff.c:838
 uevent_net_broadcast_untagged lib/kobject_uevent.c:336 [inline]
 kobject_uevent_net_broadcast lib/kobject_uevent.c:408 [inline]
 kobject_uevent_env+0x1e32/0x27c0 lib/kobject_uevent.c:592
 kobject_uevent+0x6f/0x80 lib/kobject_uevent.c:641
 device_del+0x1bbf/0x1cb0 drivers/base/core.c:2386
 hci_unregister_dev+0x5d7/0x29f0 net/bluetooth/hci_core.c:3402
 hci_uart_tty_close+0x31d/0x410 drivers/bluetooth/hci_ldisc.c:545
 tty_ldisc_close drivers/tty/tty_ldisc.c:494 [inline]
 tty_ldisc_kill drivers/tty/tty_ldisc.c:642 [inline]
 tty_ldisc_release+0x5dd/0xd50 drivers/tty/tty_ldisc.c:814
 tty_release_struct+0x4f/0x1d0 drivers/tty/tty_io.c:1612
 tty_release+0x1be2/0x1e80 drivers/tty/tty_io.c:1785
 __fput+0x4c9/0xba0 fs/file_table.c:280
 ____fput+0x37/0x40 fs/file_table.c:313
 task_work_run+0x22e/0x2a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:163 [inline]
 prepare_exit_to_usermode+0x39d/0x4d0 arch/x86/entry/common.c:194
 syscall_return_slowpath+0x90/0x610 arch/x86/entry/common.c:274
 do_syscall_64+0xdc/0x160 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
=====================================================