From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: Ze Gao <zegao2021@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Alexei Starovoitov <ast@kernel.org>,
Borislav Petkov <bp@alien8.de>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Heiko Carstens <hca@linux.ibm.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Sven Schnelle <svens@linux.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Vasily Gorbik <gor@linux.ibm.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org,
Conor Dooley <conor@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Yonghong Song <yhs@fb.com>, Ze Gao <zegao@tencent.com>
Subject: Re: [PATCH v2 2/4] fprobe: make fprobe_kprobe_handler recursion free
Date: Wed, 17 May 2023 01:03:11 +0900 [thread overview]
Message-ID: <20230517010311.f46db3f78b11cf9d92193527@kernel.org> (raw)
In-Reply-To: <CAD8CoPDFp2_+D6nykj6mu_Pr57iN+8jO-kgA_FRrcxD8C7YU+Q@mail.gmail.com>
On Tue, 16 May 2023 17:47:52 +0800
Ze Gao <zegao2021@gmail.com> wrote:
> Precisely, these that are called within kprobe_busy_{begin, end},
> which the previous patch does not resolve.
Note that kprobe_busy_{begin,end} don't need to use notrace version
because kprobe itself prohibits probing on preempt_count_{add,sub}.
Thank you,
> I will refine the commit message to make it clear.
>
> FYI, details can checked out here:
> Link: https://lore.kernel.org/linux-trace-kernel/20230516132516.c902edcf21028874a74fb868@kernel.org/
>
> Regards,
> Ze
>
> On Tue, May 16, 2023 at 5:18 PM Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Tue, May 16, 2023 at 03:18:28PM +0800, Ze Gao wrote:
> > > Current implementation calls kprobe related functions before doing
> > > ftrace recursion check in fprobe_kprobe_handler, which opens door
> > > to kernel crash due to stack recursion if preempt_count_{add, sub}
> > > is traceable.
> >
> > Which preempt_count*() are you referring to? The ones you just made
> > _notrace in the previous patch?
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
next prev parent reply other threads:[~2023-05-16 16:03 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-16 7:18 [PATCH v2 0/4] Make fprobe + rethook immune to recursion Ze Gao
2023-05-16 7:18 ` [PATCH v2 1/4] rethook: use preempt_{disable, enable}_notrace in rethook_trampoline_handler Ze Gao
2023-05-16 7:18 ` [PATCH v2 2/4] fprobe: make fprobe_kprobe_handler recursion free Ze Gao
2023-05-16 9:15 ` Peter Zijlstra
2023-05-16 9:35 ` Ze Gao
2023-05-16 9:18 ` Peter Zijlstra
2023-05-16 9:47 ` Ze Gao
2023-05-16 9:51 ` Ze Gao
2023-05-16 16:03 ` Masami Hiramatsu [this message]
2023-05-17 1:54 ` Ze Gao
2023-05-17 2:54 ` Masami Hiramatsu
2023-05-17 3:10 ` Ze Gao
2023-05-17 3:25 ` Steven Rostedt
2023-05-17 3:51 ` Masami Hiramatsu
2023-05-17 4:51 ` Ze Gao
2023-05-16 7:18 ` [PATCH v2 3/4] fprobe: add recursion detection in fprobe_exit_handler Ze Gao
2023-05-16 7:18 ` [PATCH v2 4/4] rehook, fprobe: do not trace rethook related functions Ze Gao
2023-05-16 14:20 ` Steven Rostedt
2023-05-17 2:00 ` Ze Gao
2023-05-16 16:05 ` Masami Hiramatsu
2023-05-16 21:42 ` [PATCH v2 0/4] Make fprobe + rethook immune to recursion Jiri Olsa
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