KMSAN: uninit-value in process_adv_report

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    93f54a72 instrumented.h: fix KMSAN support
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=13238a42900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fa4f3b91169c2501
dashboard link: https://syzkaller.appspot.com/bug?extid=e4244d85e5b777ac4d3d
compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
userspace arch: i386
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=108830ec900000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12f9336c900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e4244d85e5b777ac4d3d@xxxxxxxxxxxxxxxxxxxxxxxxx

Bluetooth: hci0: unknown advertising packet type: 0x2b
=====================================================
BUG: KMSAN: uninit-value in hci_bdaddr_is_rpa include/net/bluetooth/hci_core.h:1486 [inline]
BUG: KMSAN: uninit-value in process_adv_report+0x781/0x2000 net/bluetooth/hci_event.c:5409
CPU: 0 PID: 2202 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+0x1df/0x240 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_bdaddr_is_rpa include/net/bluetooth/hci_core.h:1486 [inline]
 process_adv_report+0x781/0x2000 net/bluetooth/hci_event.c:5409
 hci_le_direct_adv_report_evt net/bluetooth/hci_event.c:5837 [inline]
 hci_le_meta_evt net/bluetooth/hci_event.c:5902 [inline]
 hci_event_packet+0x1d08/0x33ee0 net/bluetooth/hci_event.c:6155
 hci_rx_work+0x95f/0xce0 net/bluetooth/hci_core.c:4705
 process_one_work+0x1540/0x1f30 kernel/workqueue.c:2269
 worker_thread+0xed2/0x23f0 kernel/workqueue.c:2415
 kthread+0x515/0x550 kernel/kthread.c:292
 ret_from_fork+0x22/0x30 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+0xb40/0x1200 mm/slub.c:4478
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x2fd/0xac0 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+0x15b/0x800 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+0xd98/0x1480 fs/read_write.c:578
 ksys_write+0x267/0x450 fs/read_write.c:631
 __do_sys_write fs/read_write.c:643 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:640
 __ia32_sys_write+0x4a/0x70 fs/read_write.c:640
 do_syscall_32_irqs_on arch/x86/entry/common.c:430 [inline]
 __do_fast_syscall_32+0x2aa/0x400 arch/x86/entry/common.c:477
 do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
=====================================================


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