> From: pet...@infradead.org
>
> I'm now trying and failing to reproduce I can't seem to make it use
> int3 today. It seems to want to use ftrace or refuses everything. I'm
> probably doing it wrong.
>
You can turn off CONFIG_KPROBES_ON_FTRACE (and also sysctl
debug.kprobes-optimization) to
> -Original Message-
> From: Masami Hiramatsu
>
> @@ -1311,24 +1257,23 @@ void kprobe_busy_end(void)
> void kprobe_flush_task(struct task_struct *tk)
> {
> struct kretprobe_instance *ri;
> - struct hlist_head *head;
> - struct hlist_node *tmp;
> - unsigned long
> From: Masami Hiramatsu
>
> 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
> -Original Message-
> From: Peter Zijlstra
> Sent: Friday, August 28, 2020 12:13 AM
> To: linux-kernel@vger.kernel.org; mhira...@kernel.org
> Cc: Eddy Wu (RD-TW) ; x...@kernel.org;
> da...@davemloft.net; rost...@goodmis.org;
> naveen.n@linux.ibm.com; anil.s.keshavamur...@intel.com;
> -Original Message-
> From: pet...@infradead.org
> Sent: Wednesday, August 26, 2020 6:26 PM
> To: Masami Hiramatsu
> Cc: Eddy Wu (RD-TW) ; linux-kernel@vger.kernel.org;
> x...@kernel.org
> Subject: Re: x86/kprobes: kretprobe fails to triggered if kprobe at function
> entry is not opt
> -Original Message-
> From: pet...@infradead.org
> Sent: Tuesday, August 25, 2020 8:09 PM
> To: Masami Hiramatsu
> Cc: Eddy Wu (RD-TW) ; linux-kernel@vger.kernel.org;
> x...@kernel.org; David S. Miller
>
> Subject: Re: x86/kprobes: kretprobe fails to triggered if kprobe at function
was sent from outside of Trend Micro. Please do not click
> > > links or open attachments unless you recognise the source of
> this
> > > email and know the content is safe.
> > >
> > >
> > > On Mon, 24 Aug 2020 12:02:58 +
> > > "eddy..
at function
> entry is not optimized (trigger by int3 breakpoint)
>
>
> This message was sent from outside of Trend Micro. Please do not click links
> or open attachments unless you recognise the source of this
> email and know the content is safe.
>
>
> On Mon, 24 A
ction
> entry is not optimized (trigger by int3 breakpoint)
>
> On Mon, Aug 24, 2020 at 12:02:58PM +, eddy...@trendmicro.com wrote:
> > After bisecting, I found this behavior seems to introduce by this
> > commit: (5.8-rc1) 0d00449c7a28a1514595630735df383dec606812 x86:
>
Greetings!
Starting from kernel 5.8 (x86_64), kretprobe handler will always missed if
corresponding kprobe on function entry is not optimized (using break point
instead).
Step to reproduce this:
1) Build the kretprobe example module (CONFIG_SAMPLE_KRETPROBES=m)
2) Disable jump optimization (`sys
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