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From:   Tong Zhang <ztong0001@gmail.com>
Date:   Tue, 25 Jan 2022 21:23:43 -0800
Message-ID: <CAA5qM4Btrnp9Te2pm0s=OuDk0ASTE3-LyLt8nf0fXKxhehXUgA@mail.gmail.com>
Subject: Re: [PATCH v1] binfmt_misc: fix crash when load/unload module
To:     Murphy Zhou <jencce.kernel@gmail.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        kernel test robot <lkp@intel.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Eric Biederman <ebiederm@xmission.com>,
        Kees Cook <keescook@chromium.org>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        llvm@lists.linux.dev, kbuild-all@lists.01.org,
        Linux Memory Management List <linux-mm@kvack.org>
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On Tue, Jan 25, 2022 at 9:04 PM Murphy Zhou <jencce.kernel@gmail.com> wrote:
>
> Still panic with this patch on Linux-next tree:
>
> [ 1128.275515] LTP: starting binfmt_misc02 (binfmt_misc02.sh)
> [ 1128.303975] CPU: 1 PID: 107182 Comm: modprobe Kdump: loaded
> Tainted: G        W         5.17.0-rc1-next-20220125+ #1
> [ 1128.305264] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
> [ 1128.305992] Call Trace:
> [ 1128.306376]  <TASK>
> [ 1128.306682]  dump_stack_lvl+0x34/0x44
> [ 1128.307211]  __register_sysctl_table+0x2c7/0x4a0
> [ 1128.307846]  ? load_module+0xb37/0xbb0
> [ 1128.308339]  ? 0xffffffffc01b6000
> [ 1128.308762]  init_misc_binfmt+0x32/0x1000 [binfmt_misc]
> [ 1128.309402]  do_one_initcall+0x44/0x200
> [ 1128.309937]  ? kmem_cache_alloc_trace+0x163/0x2c0
> [ 1128.310535]  do_init_module+0x5c/0x260
> [ 1128.311045]  __do_sys_finit_module+0xb4/0x120
> [ 1128.311603]  do_syscall_64+0x3b/0x90
> [ 1128.312088]  entry_SYSCALL_64_after_hwframe+0x44/0xae
> [ 1128.312755] RIP: 0033:0x7f929ab85fbd
>
> Testing patch on Linus tree.

Hi Murphy,
Did you apply this patch?
Link: https://lkml.kernel.org/r/20220124181812.1869535-2-ztong0001@gmail.com
I tested it on top of the current master branch and it works on my
setup using the reproducer I mentioned.
Could you share your test script?
Thanks,
- Tong