Hello,
syzbot found the following crash on:
HEAD commit: 8f3d9f35 Linux 5.7-rc1
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1182b24fe00000
kernel config: https://syzkaller.appspot.com/x/.config?x=11f10cc27c63cade
dashboard link: https://syzkaller.appspot.com/bug?extid=2e9900a1e1b3c9c96a77
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 10817 at lib/refcount.c:28 refcount_warn_saturate+0x15b/0x1a0 lib/refcount.c:28
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 10817 Comm: kworker/0:7 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events do_enable_set
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1e9/0x30e lib/dump_stack.c:118
panic+0x264/0x7a0 kernel/panic.c:221
__warn+0x209/0x210 kernel/panic.c:582
report_bug+0x1ac/0x2d0 lib/bug.c:195
fixup_bug arch/x86/kernel/traps.c:175 [inline]
do_error_trap+0xca/0x1c0 arch/x86/kernel/traps.c:267
do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:286
invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:refcount_warn_saturate+0x15b/0x1a0 lib/refcount.c:28
Code: c7 9a a9 f2 88 31 c0 e8 a3 fb ac fd 0f 0b eb 85 e8 5a e7 da fd c6 05 10 48 cf 05 01 48 c7 c7 c6 a9 f2 88 31 c0 e8 85 fb ac fd <0f> 0b e9 64 ff ff ff e8 39 e7 da fd c6 05 f0 47 cf 05 01 48 c7 c7
RSP: 0000:ffffc900016d7c48 EFLAGS: 00010246
RAX: 8e9964d9ee901300 RBX: 0000000000000003 RCX: ffff888089a0e5c0
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff815cbca9 R09: ffffed1015d06660
R10: ffffed1015d06660 R11: 0000000000000000 R12: ffffffff895f43c8
R13: dffffc0000000000 R14: ffff88809365b018 R15: ffff8880ae83b400
do_enable_set+0x63a/0x8d0 net/bluetooth/6lowpan.c:1075
process_one_work+0x76e/0xfd0 kernel/workqueue.c:2268
worker_thread+0xa7f/0x1450 kernel/workqueue.c:2414
kthread+0x353/0x380 kernel/kthread.c:268
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..
---
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On Sun, Sep 6, 2020 at 7:31 AM syzbot
<[email protected]> wrote:
>
> syzbot suspects this issue was fixed by commit:
>
> commit b83764f9220a4a14525657466f299850bbc98de9
> Author: Miao-chen Chou <[email protected]>
> Date: Tue Jun 30 03:15:00 2020 +0000
>
> Bluetooth: Fix kernel oops triggered by hci_adv_monitors_clear()
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=115a4245900000
> start commit: fffe3ae0 Merge tag 'for-linus-hmm' of git://git.kernel.org..
> git tree: upstream
> kernel config: https://syzkaller.appspot.com/x/.config?x=226c7a97d80bec54
> dashboard link: https://syzkaller.appspot.com/bug?extid=2e9900a1e1b3c9c96a77
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12b3efea900000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11131284900000
>
> If the result looks correct, please mark the issue as fixed by replying with:
>
> #syz fix: Bluetooth: Fix kernel oops triggered by hci_adv_monitors_clear()
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
#syz fix: Bluetooth: Fix kernel oops triggered by hci_adv_monitors_clear()