From: Masami Hiramatsu <mhiramat@kernel.org>
To: peterz@infradead.org
Cc: "Eddy_Wu@trendmicro.com" <Eddy_Wu@trendmicro.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"davem@davemloft.net" <davem@davemloft.net>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"naveen.n.rao@linux.ibm.com" <naveen.n.rao@linux.ibm.com>,
"anil.s.keshavamurthy@intel.com" <anil.s.keshavamurthy@intel.com>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"cameron@moodycamel.com" <cameron@moodycamel.com>,
"oleg@redhat.com" <oleg@redhat.com>,
"will@kernel.org" <will@kernel.org>,
"paulmck@kernel.org" <paulmck@kernel.org>
Subject: Re: [RFC][PATCH 3/7] kprobes: Remove kretprobe hash
Date: Fri, 28 Aug 2020 23:19:20 +0900 [thread overview]
Message-ID: <20200828231920.4cb817dd9c624703ecfedc5d@kernel.org> (raw)
In-Reply-To: <20200828135824.GD1362448@hirez.programming.kicks-ass.net>
On Fri, 28 Aug 2020 15:58:24 +0200
peterz@infradead.org wrote:
> On Fri, Aug 28, 2020 at 10:51:13PM +0900, Masami Hiramatsu wrote:
>
> > OK, schedule function will be the key. I guess the senario is..
> >
> > 1) kretporbe replace the return address with kretprobe_trampoline on task1's kernel stack
> > 2) the task1 forks task2 before returning to the kretprobe_trampoline
> > 3) while copying the process with the kernel stack, task2->kretprobe_instances.first = NULL
> > 4) task2 returns to the kretprobe_trampoline
> > 5) Bomb!
> >
> > Hmm, we need to fixup the kernel stack when copying process.
>
> How would that scenario have been avoided in the old code? Because there
> task2 would have a different has and not have found a kretprobe_instance
> either.
Good question, I think this bug has not been solved in old code too.
Let me check.
Thanks,
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2020-08-28 14:19 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-27 16:12 [RFC][PATCH 0/7] kprobes: Make kretprobes lockless Peter Zijlstra
2020-08-27 16:12 ` [RFC][PATCH 1/7] llist: Add nonatomic __llist_add() Peter Zijlstra
2020-08-27 16:12 ` [RFC][PATCH 2/7] sched: Fix try_invoke_on_locked_down_task() semantics Peter Zijlstra
2020-08-27 16:12 ` [RFC][PATCH 3/7] kprobes: Remove kretprobe hash Peter Zijlstra
2020-08-27 18:00 ` Masami Hiramatsu
2020-08-28 8:44 ` peterz
2020-08-28 9:07 ` Masami Hiramatsu
2020-08-28 4:44 ` Masami Hiramatsu
2020-08-28 13:11 ` Eddy_Wu
2020-08-28 13:38 ` peterz
2020-08-28 13:51 ` Masami Hiramatsu
2020-08-28 13:58 ` peterz
2020-08-28 14:19 ` Masami Hiramatsu [this message]
2020-08-28 14:11 ` Eddy_Wu
2020-08-28 14:19 ` peterz
2020-08-28 14:41 ` Masami Hiramatsu
2020-08-28 14:49 ` Masami Hiramatsu
2020-08-27 16:12 ` [RFC][PATCH 4/7] kprobe: Dont kfree() from breakpoint context Peter Zijlstra
2020-08-27 16:12 ` [RFC][PATCH 5/7] asm-generic/atomic: Add try_cmpxchg() fallbacks Peter Zijlstra
2020-08-27 16:12 ` [RFC][PATCH 6/7] freelist: Lock less freelist Peter Zijlstra
2020-08-27 16:37 ` peterz
[not found] ` <CAFCw3doX6KK5DwpG_OB331Mdw8uYeVqn8YPTjKh_a-m7ZB9+3A@mail.gmail.com>
2020-08-27 16:56 ` peterz
2020-08-27 17:00 ` Cameron
2020-08-27 19:08 ` Boqun Feng
2020-08-27 19:57 ` Cameron
2020-08-28 1:34 ` Boqun Feng
2020-08-28 4:03 ` Lai Jiangshan
2020-08-28 14:46 ` Oleg Nesterov
2020-08-28 15:29 ` peterz
2020-08-29 3:05 ` Cameron
2020-08-27 16:12 ` [RFC][PATCH 7/7] kprobes: Replace rp->free_instance with freelist Peter Zijlstra
2020-08-28 8:48 ` peterz
2020-08-28 9:13 ` Masami Hiramatsu
2020-08-28 9:18 ` peterz
2020-08-28 10:44 ` Masami Hiramatsu
2020-08-29 2:29 ` Cameron
2020-08-29 2:31 ` Cameron
2020-08-29 9:15 ` Masami Hiramatsu
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