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From:   Yi Zhang <yi.zhang@redhat.com>
Date:   Mon, 18 Sep 2023 18:20:41 +0800
Message-ID: <CAHj4cs-6M+fORJOGOxH3sO5BytBwi4y9hcnS+xQ3wLZO20UXWg@mail.gmail.com>
Subject: Re: [czhong@redhat.com: [bug report] WARNING: CPU: 121 PID: 93233 at
 fs/dcache.c:365 __dentry_kill+0x214/0x278]
To:     Baokun Li <libaokun1@huawei.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ming Lei <ming.lei@redhat.com>, mark.rutland@arm.com,
        Christian Brauner <brauner@kernel.org>,
        linux-fsdevel@vger.kernel.org,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
        Changhui Zhong <czhong@redhat.com>,
        yangerkun <yangerkun@huawei.com>,
        "zhangyi (F)" <yi.zhang@huawei.com>,
        Kees Cook <keescook@chromium.org>,
        chengzhihao <chengzhihao1@huawei.com>
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On Mon, Sep 18, 2023 at 9:10=E2=80=AFAM Baokun Li <libaokun1@huawei.com> wr=
ote:
>
> On 2023/9/17 17:10, Peter Zijlstra wrote:
> > On Sat, Sep 16, 2023 at 02:55:47PM +0800, Baokun Li wrote:
> >> On 2023/9/13 16:59, Yi Zhang wrote:
> >>> The issue still can be reproduced on the latest linux tree[2].
> >>> To reproduce I need to run about 1000 times blktests block/001, and
> >>> bisect shows it was introduced with commit[1], as it was not 100%
> >>> reproduced, not sure if it's the culprit?
> >>>
> >>>
> >>> [1] 9257959a6e5b locking/atomic: scripts: restructure fallback ifdeff=
ery
> >> Hello, everyone=EF=BC=81
> >>
> >> We have confirmed that the merge-in of this patch caused hlist_bl_lock
> >> (aka, bit_spin_lock) to fail, which in turn triggered the issue above.
> >> [root@localhost ~]# insmod mymod.ko
> >> [   37.994787][  T621] >>> a =3D 725, b =3D 724
> >> [   37.995313][  T621] ------------[ cut here ]------------
> >> [   37.995951][  T621] kernel BUG at fs/mymod/mymod.c:42!
> >> [r[  oo 3t7@.l996o4c61al]h[o s T6t21] ~ ]#Int ernal error: Oops - BUG:
> >> 00000000f2000800 [#1] SMP
> >> [   37.997420][  T621] Modules linked in: mymod(E)
> >> [   37.997891][  T621] CPU: 9 PID: 621 Comm: bl_lock_thread2 Tainted:
> >> G            E      6.4.0-rc2-00034-g9257959a6e5b-dirty #117
> >> [   37.999038][  T621] Hardware name: linux,dummy-virt (DT)
> >> [   37.999571][  T621] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT=
 -SSBS
> >> BTYPE=3D--)
> >> [   38.000344][  T621] pc : increase_ab+0xcc/0xe70 [mymod]
> >> [   38.000882][  T621] lr : increase_ab+0xcc/0xe70 [mymod]
> >> [   38.001416][  T621] sp : ffff800008b4be40
> >> [   38.001822][  T621] x29: ffff800008b4be40 x28: 0000000000000000 x27=
:
> >> 0000000000000000
> >> [   38.002605][  T621] x26: 0000000000000000 x25: 0000000000000000 x24=
:
> >> 0000000000000000
> >> [   38.003385][  T621] x23: ffffd9930c698190 x22: ffff800008a0ba38 x21=
:
> >> 0000000000000001
> >> [   38.004174][  T621] x20: ffffffffffffefff x19: ffffd9930c69a580 x18=
:
> >> 0000000000000000
> >> [   38.004955][  T621] x17: 0000000000000000 x16: ffffd9933011bd38 x15=
:
> >> ffffffffffffffff
> >> [   38.005754][  T621] x14: 0000000000000000 x13: 205d313236542020 x12=
:
> >> ffffd99332175b80
> >> [   38.006538][  T621] x11: 0000000000000003 x10: 0000000000000001 x9 =
:
> >> ffffd9933022a9d8
> >> [   38.007325][  T621] x8 : 00000000000bffe8 x7 : c0000000ffff7fff x6 =
:
> >> ffffd993320b5b40
> >> [   38.008124][  T621] x5 : ffff0001f7d1c708 x4 : 0000000000000000 x3 =
:
> >> 0000000000000000
> >> [   38.008912][  T621] x2 : 0000000000000000 x1 : 0000000000000000 x0 =
:
> >> 0000000000000015
> >> [   38.009709][  T621] Call trace:
> >> [   38.010035][  T621]  increase_ab+0xcc/0xe70 [mymod]
> >> [   38.010539][  T621]  kthread+0xdc/0xf0
> >> [   38.010927][  T621]  ret_from_fork+0x10/0x20
> >> [   38.011370][  T621] Code: 17ffffe0 90000020 91044000 9400000d (d421=
0000)
> >> [   38.012067][  T621] ---[ end trace 0000000000000000 ]---
> > Is this arm64 or something? You seem to have forgotten to mention what
> > platform you're using.
> >
> Sorry for the late reply.
> We tested both x86 and arm64, and the problem is only encountered under
> arm64.

Yeah, my reproduced environment is also aarch64.


>
> --
> With Best Regards,
> Baokun Li
> .
>


--=20
Best Regards,
  Yi Zhang