linux-kernel - Re: [PATCH] perf callchain: Fix suspicious RCU usage in get_callchain

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <874829ba-00b9-49cd-8f67-a4c33a8f409f@gmail.com>
Date: Wed, 28 Jan 2026 16:19:14 +0800
From: Tao Chen <chen.dylane@...il.com>
To: Qing Wang <wangqing7171@...il.com>, andrii.nakryiko@...il.com
Cc: acme@...nel.org, adrian.hunter@...el.com,
 alexander.shishkin@...ux.intel.com, bpf@...r.kernel.org, irogers@...gle.com,
 jolsa@...nel.org, linux-kernel@...r.kernel.org,
 linux-perf-users@...r.kernel.org, mark.rutland@....com, mingo@...hat.com,
 namhyung@...nel.org, peterz@...radead.org, radoslaw.zielonek@...il.com,
 syzbot+72a43cdb78469f7fbad1@...kaller.appspotmail.com
Subject: Re: [PATCH] perf callchain: Fix suspicious RCU usage in
 get_callchain_entry()

在 2026/1/28 14:26, Qing Wang 写道:
> On Fri, 19 Jul 2024 at 01:41, Andrii Nakryiko <andrii.nakryiko@...il.com> wrote:
>> Which is what I'm doing in [0]. Radoslaw, can you please help
>> validating if those changes are enough to fix this issue or we need to
>> do some more?
>>
>>    [0] https://patchwork.kernel.org/project/netdevbpf/patch/20240709204245.3=
>> 847811-10-andrii@...nel.org/
>>
>>>
>>>> ---
>>>>   kernel/events/callchain.c | 11 +++++++++--
>>>>   1 file changed, 9 insertions(+), 2 deletions(-)
>>>>
> 
> Hi,
> 
> I found this issue still exists after your patch in upstream and I have a
> patch to fix it.
> 
> Patch here: https://lore.kernel.org/all/20260128061753.1857803-1-wangqing7171@gmail.com/T/
> 
> Looking forward to your review.
> 
> --
> Best regards,
> Qing
> 

Hi Qing,

I have a change that will remove RCU. As Andrii pointed out, using 
get_callchain_entry without RCU lock in BPF appears to be safe for now. 
Please point out if I've missed anything.

https://lore.kernel.org/bpf/fb745675-e25c-4dcc-be4b-4a4411056755@linux.dev/T/#mc0fc5e0fec2e6456f72f402308fd4e397ba19d09

-- 
Best Regards
Tao Chen