From: Masami Hiramatsu <mhiramat@kernel.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: davem@davemloft.net, daniel@iogearbox.net, nborisov@suse.com,
peterz@infradead.org, rostedt@goodmis.org, mhiramat@kernel.org,
bpf@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH bpf] bpf: Unbreak BPF_PROG_TYPE_KPROBE when kprobe is called via do_int3
Date: Wed, 3 Feb 2021 21:40:51 +0900 [thread overview]
Message-ID: <20210203214051.f9cd7c0c0d096b02efbd01c3@kernel.org> (raw)
In-Reply-To: <20210203070636.70926-1-alexei.starovoitov@gmail.com>
On Tue, 2 Feb 2021 23:06:36 -0800
Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> From: Alexei Starovoitov <ast@kernel.org>
>
> The commit 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()")
> converted do_int3 handler to be "NMI-like".
> That made old if (in_nmi()) check abort execution of bpf programs
> attached to kprobe when kprobe is firing via int3
> (For example when kprobe is placed in the middle of the function).
> Remove the check to restore user visible behavior.
>
> Fixes: 0d00449c7a28 ("x86: Replace ist_enter() with nmi_enter()")
> Reported-by: Nikolay Borisov <nborisov@suse.com>
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Looks good to me :)
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Thanks!
> ---
> kernel/trace/bpf_trace.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 6c0018abe68a..764400260eb6 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -96,9 +96,6 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
> {
> unsigned int ret;
>
> - if (in_nmi()) /* not supported yet */
> - return 1;
> -
> cant_sleep();
>
> if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
> --
> 2.24.1
>
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2021-02-03 12:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-03 7:06 [PATCH bpf] bpf: Unbreak BPF_PROG_TYPE_KPROBE when kprobe is called via do_int3 Alexei Starovoitov
2021-02-03 7:09 ` Nikolay Borisov
2021-02-03 7:11 ` Alexei Starovoitov
2021-02-03 12:40 ` Masami Hiramatsu [this message]
2021-02-03 20:40 ` patchwork-bot+netdevbpf
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