KMSAN: uninit-value in hci_chan_lookup

KMSAN: uninit-value in hci_chan_lookup_handle
Status: upstream: reported C repro on 2020/08/15 17:19
Reported-by: syzbot+4c14a8f574461e1c3659@syzkaller.appspotmail.com
First crash: 428d, last: 427d

Patch testing requests:
Created	Duration	User	Patch	Repo	Result
2020/09/04 18:54	14m	dragonjetli@gmail.com	patch	https://github.com/google/kmsan.git master	report log
2020/09/04 10:59	22m	dragonjetli@gmail.com	patch	https://github.com/google/kmsan.git master	OK
2020/09/04 10:30	13m	dragonjetli@gmail.com	patch	https://github.com/google/kmsan.git master	report log
2020/09/04 10:15	0m	dragonjetli@gmail.com	patch	https://github.com/google/kmsan.git master	error
2020/09/04 06:02	19m	dragonjetli@gmail.com	patch	https://github.com/google/kmsan.git master	OK
2020/09/04 05:57	5m	dragonjetli@gmail.com	patch	https://github.com/google/kmsan.git master	error
2020/09/04 03:08	5m	dragonjetli@gmail.com	patch	https://github.com/google/kmsan.git master	error
2020/09/02 23:49	13m	dragonjetli@gmail.com		https://github.com/google/kmsan.git master	report log
2020/08/20 09:16	13m	anmol.karan123@gmail.com		https://github.com/google/kmsan.git master	report log

Sample crash report:

=====================================================
BUG: KMSAN: uninit-value in __hci_chan_lookup_handle net/bluetooth/hci_conn.c:1741 [inline]
BUG: KMSAN: uninit-value in hci_chan_lookup_handle+0x1e3/0x310 net/bluetooth/hci_conn.c:1757
CPU: 1 PID: 2280 Comm: kworker/u5:0 Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci0 hci_rx_work
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 __hci_chan_lookup_handle net/bluetooth/hci_conn.c:1741 [inline]
 hci_chan_lookup_handle+0x1e3/0x310 net/bluetooth/hci_conn.c:1757
 hci_disconn_loglink_complete_evt net/bluetooth/hci_event.c:4992 [inline]
 hci_event_packet+0x14e10/0x39d30 net/bluetooth/hci_event.c:6176
 hci_rx_work+0x6df/0xd30 net/bluetooth/hci_core.c:4705
 process_one_work+0x1688/0x2140 kernel/workqueue.c:2269
 worker_thread+0x10bc/0x2730 kernel/workqueue.c:2415
 kthread+0x551/0x590 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80
 slab_alloc_node mm/slub.c:2839 [inline]
 __kmalloc_node_track_caller+0xeab/0x12e0 mm/slub.c:4478
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x35f/0xb30 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1083 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:377 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:165 [inline]
 vhci_write+0x18a/0x890 drivers/bluetooth/hci_vhci.c:285
 call_write_iter include/linux/fs.h:1908 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0xf9a/0x17c0 fs/read_write.c:578
 ksys_write+0x275/0x500 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:640
 __x64_sys_write+0x4a/0x70 fs/read_write.c:640
 do_syscall_64+0xad/0x160 arch/x86/entry/common.c:386
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
=====================================================

Crashes (3):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro
ci-upstream-kmsan-gce	2020/08/16 00:29	https://github.com/google/kmsan.git master	ce8056d1f79e	424dd8e7	.config	log	report	syz	C
ci-upstream-kmsan-gce	2020/08/15 23:27	https://github.com/google/kmsan.git master	ce8056d1f79e	424dd8e7	.config	log	report	syz	C
ci-upstream-kmsan-gce	2020/08/15 01:46	https://github.com/google/kmsan.git master	ce8056d1f79e	424dd8e7	.config	log	report	syz	C