Subject: [syzbot] KMSAN: uninit-value in hci_conn_request_evt

From: syzbot <[email-masked]>
Date: Thu, 28 Oct 2021 23:35:20 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    82e66ad2e586 kmsan: core: better comment
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=157ae0e2b00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3ea742e10a5398fb
dashboard link: https://syzkaller.appspot.com/bug?extid=8f84cf3ec5c288e779ef
compiler:       clang version 14.0.0 ([email-masked]:llvm/llvm-project.git 0996585c8e3b3d409494eb5f1cad714b9e1f7fb5), GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

=====================================================
BUG: KMSAN: uninit-value in hci_proto_connect_ind include/net/bluetooth/hci_core.h:1460 [inline]
BUG: KMSAN: uninit-value in hci_conn_request_evt+0x220/0x1290 net/bluetooth/hci_event.c:2783
 hci_proto_connect_ind include/net/bluetooth/hci_core.h:1460 [inline]
 hci_conn_request_evt+0x220/0x1290 net/bluetooth/hci_event.c:2783
 hci_event_packet+0x1489/0x22e0 net/bluetooth/hci_event.c:6315
 hci_rx_work+0x6ae/0xd10 net/bluetooth/hci_core.c:5136
 process_one_work+0xdc7/0x1760 kernel/workqueue.c:2297
 worker_thread+0x1101/0x22b0 kernel/workqueue.c:2444
 kthread+0x66b/0x780 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

Uninit was created at:
 slab_alloc_node mm/slub.c:3221 [inline]
 __kmalloc_node_track_caller+0x8d2/0x1340 mm/slub.c:4955
 kmalloc_reserve net/core/skbuff.c:355 [inline]
 __alloc_skb+0x4db/0xe40 net/core/skbuff.c:426
 alloc_skb include/linux/skbuff.h:1116 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:389 [inline]
 vhci_get_user drivers/bluetooth/hci_vhci.c:165 [inline]
 vhci_write+0x182/0x8f0 drivers/bluetooth/hci_vhci.c:285
 call_write_iter include/linux/fs.h:2163 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x1295/0x1f20 fs/read_write.c:594
 ksys_write+0x28c/0x520 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0xdb/0x120 fs/read_write.c:656
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x44/0xae
=====================================================
Kernel panic - not syncing: panic_on_kmsan set ...
CPU: 1 PID: 6390 Comm: kworker/u5:1 Tainted: G    B             5.15.0-rc2-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:88 [inline]
 dump_stack_lvl+0x1ff/0x28e lib/dump_stack.c:106
 dump_stack+0x25/0x28 lib/dump_stack.c:113
 panic+0x44f/0xdeb kernel/panic.c:232
 kmsan_report+0x2ee/0x300 mm/kmsan/report.c:168
 __msan_warning+0xb4/0x100 mm/kmsan/instrumentation.c:199
 hci_proto_connect_ind include/net/bluetooth/hci_core.h:1460 [inline]
 hci_conn_request_evt+0x220/0x1290 net/bluetooth/hci_event.c:2783
 hci_event_packet+0x1489/0x22e0 net/bluetooth/hci_event.c:6315
 hci_rx_work+0x6ae/0xd10 net/bluetooth/hci_core.c:5136
 process_one_work+0xdc7/0x1760 kernel/workqueue.c:2297
 worker_thread+0x1101/0x22b0 kernel/workqueue.c:2444
 kthread+0x66b/0x780 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30
Kernel Offset: disabled
Rebooting in 86400 seconds..

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