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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Tue, 13 Feb 2018 21:15:27 +0100
Message-ID: <CACT4Y+ai9tCO6bHJ5G7EhBbcxtrd2ZkKXbi+xDEpjwh9EwXQXw@mail.gmail.com>
Subject: Re: BUG: free active (active state 0) object type: work_struct hint: strp_work
To:     Tom Herbert <tom@quantonium.net>
Cc:     syzbot <syzbot+3c6c745b0d2f341bbf50@syzkaller.appspotmail.com>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Biggers <ebiggers@google.com>,
        John Fastabend <john.fastabend@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux Kernel Network Developers <netdev@vger.kernel.org>,
        syzkaller-bugs@googlegroups.com,
        Cong Wang <xiyou.wangcong@gmail.com>
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On Thu, Jan 4, 2018 at 8:36 PM, Tom Herbert <tom@quantonium.net> wrote:
> On Thu, Jan 4, 2018 at 4:10 AM, syzbot
> <syzbot+3c6c745b0d2f341bbf50@syzkaller.appspotmail.com> wrote:
>> Hello,
>>
>> syzkaller hit the following crash on
>> 6bb8824732f69de0f233ae6b1a8158e149627b38
>> git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git/master
>> compiler: gcc (GCC) 7.1.1 20170620
>> .config is attached
>> Raw console output is attached.
>> Unfortunately, I don't have any reproducer for this bug yet.
>>
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+3c6c745b0d2f341bbf50@syzkaller.appspotmail.com
>> It will help syzbot understand when the bug is fixed. See footer for
>> details.
>> If you forward the report, please keep this part and the footer.
>>
>> Use struct sctp_assoc_value instead
>> sctp: [Deprecated]: syz-executor4 (pid 12483) Use of int in maxseg socket
>> option.
>> Use struct sctp_assoc_value instead
>> ------------[ cut here ]------------
>> ODEBUG: free active (active state 0) object type: work_struct hint:
>> strp_work+0x0/0xf0 net/strparser/strparser.c:381
>> WARNING: CPU: 1 PID: 3502 at lib/debugobjects.c:291
>> debug_print_object+0x166/0x220 lib/debugobjects.c:288
>> Kernel panic - not syncing: panic_on_warn set ...
>>
>> CPU: 1 PID: 3502 Comm: kworker/u4:4 Not tainted 4.15.0-rc5+ #170
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> Google 01/01/2011
>> Workqueue: kkcmd kcm_tx_work
>> Call Trace:
>>  __dump_stack lib/dump_stack.c:17 [inline]
>>  dump_stack+0x194/0x257 lib/dump_stack.c:53
>>  panic+0x1e4/0x41c kernel/panic.c:183
>>  __warn+0x1dc/0x200 kernel/panic.c:547
>>  report_bug+0x211/0x2d0 lib/bug.c:184
>>  fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178
>>  fixup_bug arch/x86/kernel/traps.c:247 [inline]
>>  do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296
>>  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
>>  invalid_op+0x22/0x40 arch/x86/entry/entry_64.S:1061
>> RIP: 0010:debug_print_object+0x166/0x220 lib/debugobjects.c:288
>> RSP: 0018:ffff8801c0ee7068 EFLAGS: 00010086
>> RAX: dffffc0000000008 RBX: 0000000000000003 RCX: ffffffff8159bc3e
>> RDX: 0000000000000000 RSI: 1ffff100381dcdc8 RDI: ffff8801db317dd0
>> RBP: ffff8801c0ee70a8 R08: 0000000000000000 R09: 1ffff100381dcd9a
>> R10: ffffed00381dce3c R11: ffffffff86137ad8 R12: 0000000000000001
>> R13: ffffffff86113480 R14: ffffffff8560dc40 R15: ffffffff8146e5f0
>>  __debug_check_no_obj_freed lib/debugobjects.c:745 [inline]
>>  debug_check_no_obj_freed+0x662/0xf1f lib/debugobjects.c:774
>>  kmem_cache_free+0x253/0x2a0 mm/slab.c:3745
>
> I believe we just need to defer kmem_cache_free to call_rcu.


Hi Tom,

Was this ever submitted? I don't any such change in net/kcm/kcmsock.c.