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From: Oleg Nesterov <oleg@redhat.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>, Aleksa Sarai <cyphar@cyphar.com>,
	Eyal Birger <eyal.birger@gmail.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-trace-kernel@vger.kernel.org,
	BPF-dev-list <bpf@vger.kernel.org>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	peterz@infradead.org, tglx@linutronix.de, bp@alien8.de,
	x86@kernel.org, linux-api@vger.kernel.org,
	Andrii Nakryiko <andrii@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	"rostedt@goodmis.org" <rostedt@goodmis.org>,
	rafi@rbk.io, Shmulik Ladkani <shmulik.ladkani@gmail.com>
Subject: Re: Crash when attaching uretprobes to processes running in Docker
Date: Tue, 14 Jan 2025 12:21:07 +0100	[thread overview]
Message-ID: <20250114112106.GC19816@redhat.com> (raw)
In-Reply-To: <20250114190521.0b69a1af64cac41106101154@kernel.org>

On 01/14, Masami Hiramatsu wrote:
>
> On Tue, 14 Jan 2025 10:22:20 +0100
> Jiri Olsa <olsajiri@gmail.com> wrote:
>
> > @@ -418,6 +439,9 @@ SYSCALL_DEFINE0(uretprobe)
> >  	regs->r11 = regs->flags;
> >  	regs->cx  = regs->ip;
> >
> > +	/* zero rbx to signal trampoline that uretprobe syscall was executed */
> > +	regs->bx  = 0;
>
> Can we just return -ENOSYS as like as other syscall instead of
> using rbx as a side channel?
> We can carefully check the return address is not -ERRNO when set up
> and reserve the -ENOSYS for this use case.

Not sure I understand...

But please not that the uretprobed function can return any value
including -ENOSYS, and this is what sys_uretprobe() has to return.

Oleg.


  reply	other threads:[~2025-01-14 11:21 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-10 15:12 Crash when attaching uretprobes to processes running in Docker Eyal Birger
2025-01-10 15:25 ` Aleksa Sarai
2025-01-11 18:40   ` Jiri Olsa
2025-01-14  9:22     ` Jiri Olsa
2025-01-14 10:05       ` Masami Hiramatsu
2025-01-14 11:21         ` Oleg Nesterov [this message]
2025-01-14 14:21           ` Jiri Olsa
2025-01-17  1:23             ` Masami Hiramatsu
2025-01-17  1:57               ` Oleg Nesterov
2025-01-14 10:42       ` Peter Zijlstra
2025-01-14 11:01         ` Oleg Nesterov
2025-01-14 12:02           ` Peter Zijlstra
2025-01-14 12:32             ` Oleg Nesterov
2025-01-14 14:07               ` Peter Zijlstra
2025-01-14 17:43                 ` Oleg Nesterov
2025-01-14 10:58       ` Oleg Nesterov
2025-01-14 14:19         ` Jiri Olsa
2025-01-14 19:21           ` Andrii Nakryiko
2025-01-14 20:39             ` Oleg Nesterov
2025-01-14 21:45               ` Andrii Nakryiko
2025-01-14 22:10                 ` Oleg Nesterov
2025-01-14 23:52                   ` Andrii Nakryiko
2025-01-15  0:09                     ` Eyal Birger
2025-01-15  0:50                       ` Oleg Nesterov
2025-01-15  5:45                         ` Shmulik Ladkani
2025-01-15 15:51                           ` Oleg Nesterov
2025-01-17 11:41                 ` Peter Zijlstra
2025-01-17 17:53                   ` Andrii Nakryiko
2025-01-14 14:08       ` Eyal Birger
2025-01-14 14:33         ` Oleg Nesterov
2025-01-14 14:56           ` Jiri Olsa
2025-01-14 17:25             ` Oleg Nesterov
2025-01-15  9:36               ` Jiri Olsa
2025-01-15 13:24                 ` Eyal Birger
2025-01-15 13:25                 ` Jiri Olsa
2025-01-15 15:06                 ` Oleg Nesterov
2025-01-15 17:56                   ` Alexei Starovoitov
2025-01-15 18:20                     ` Andrii Nakryiko
2025-01-15 18:40                     ` Oleg Nesterov
2025-01-15 18:48                       ` Eyal Birger
2025-01-15 19:03                         ` Oleg Nesterov
2025-01-15 21:14                           ` Eyal Birger
2025-01-16 14:39                             ` Oleg Nesterov
2025-01-16 14:47                               ` Eyal Birger
2025-01-16 15:31                                 ` Oleg Nesterov
2025-01-16 17:11                                   ` Eyal Birger
2025-01-17  0:48                                     ` Oleg Nesterov

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