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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Josef Bacik <josef@toxicpanda.com>
Cc: Yonghong Song <yhs@fb.com>, bpf <bpf@vger.kernel.org>,
Network Development <netdev@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH bpf] bpf: use get_file_rcu() instead of get_file() for task_file iterator
Date: Mon, 17 Aug 2020 14:49:02 -0700 [thread overview]
Message-ID: <CAADnVQJBCWYm-CiYiJMCLVT03kquZKqdTRMJP7CmL_BWr2Cpnw@mail.gmail.com> (raw)
In-Reply-To: <b1254561-4530-f2d8-bd10-98cb426a727d@toxicpanda.com>
On Mon, Aug 17, 2020 at 11:27 AM Josef Bacik <josef@toxicpanda.com> wrote:
>
> On 8/17/20 1:42 PM, Yonghong Song wrote:
> > With latest `bpftool prog` command, we observed the following kernel
> > panic.
> > BUG: kernel NULL pointer dereference, address: 0000000000000000
> >
> > This patch used get_file_rcu() which only grabs a file if the
> > file->f_count is not zero. This is to ensure the file pointer
> > is always valid. The above reproducer did not fail for more
> > than 30 minutes.
> >
> > Fixes: eaaacd23910f ("bpf: Add task and task/file iterator targets")
> > Suggested-by: Josef Bacik <josef@toxicpanda.com>
> > Signed-off-by: Yonghong Song <yhs@fb.com>
> > ---
>
> Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Applied. Thanks
prev parent reply other threads:[~2020-08-17 21:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-17 17:42 Yonghong Song
2020-08-17 18:27 ` Josef Bacik
2020-08-17 21:49 ` Alexei Starovoitov [this message]
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