From: Jiri Olsa <olsajiri@gmail.com>
To: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Jiri Olsa <olsajiri@gmail.com>,
bot+bpf-ci@kernel.org, mhiramat@kernel.org, rostedt@goodmis.org,
song@kernel.org, peterz@infradead.org, bpf@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, x86@kernel.org, yhs@fb.com,
songliubraving@fb.com, andrii@kernel.org, ast@kernel.org,
daniel@iogearbox.net, martin.lau@kernel.org, eddyz87@gmail.com,
yonghong.song@linux.dev, clm@meta.com, ihor.solodrai@linux.dev
Subject: Re: [PATCH 1/3] Revert "perf/x86: Always store regs->ip in perf_callchain_kernel()"
Date: Wed, 29 Oct 2025 08:17:05 +0100 [thread overview]
Message-ID: <aQG_calHM0E7ou67@krava> (raw)
In-Reply-To: <xnx66p7w3qstst4ixj356dnzexrpsjy52tfwthp5kytv5yagcf@4ngtq5rrgqzj>
On Tue, Oct 28, 2025 at 08:39:33PM -0700, Josh Poimboeuf wrote:
> On Mon, Oct 27, 2025 at 11:38:50PM +0100, Jiri Olsa wrote:
> > On Mon, Oct 27, 2025 at 01:19:52PM -0700, Josh Poimboeuf wrote:
> > > On Mon, Oct 27, 2025 at 01:52:18PM +0000, bot+bpf-ci@kernel.org wrote:
> > > > Does this revert re-introduce the BPF selftest failure that was fixed in
> > > > 2019? The test tools/testing/selftests/bpf/prog_tests/stacktrace_map_raw_tp.c
> > > > still exists in the kernel tree.
> > >
> > > I have the same question. And note there may be subtle differences
> > > between the frame pointer and ORC unwinders. The testcase would need to
> > > pass for both.
> >
> > as I wrote in the other email that test does not check ips directly,
> > it just compare stacks taken from bpf_get_stackid and bpf_get_stack
> > helpers.. so it passes for both orc and frame pointer unwinder
>
> Ok. So the original fix wasn't actually a fix at all? It would be good
> to understand that and mention it in the commit log. Otherwise it's not
> clear why it's ok to revert a fix with no real explanation.
I think it was a fix when it was pushed 6 years ago, but some
unwind change along that time made it redundant, I'll try to
find what the change was
jirka
next prev parent reply other threads:[~2025-10-29 7:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-27 13:13 [PATCH 0/3] x86/fgraph,bpf: Fix ORC stack unwind from return probe Jiri Olsa
2025-10-27 13:13 ` [PATCH 1/3] Revert "perf/x86: Always store regs->ip in perf_callchain_kernel()" Jiri Olsa
2025-10-27 13:52 ` bot+bpf-ci
2025-10-27 20:19 ` Josh Poimboeuf
2025-10-27 22:38 ` Jiri Olsa
2025-10-29 3:39 ` Josh Poimboeuf
2025-10-29 7:17 ` Jiri Olsa [this message]
2025-10-30 21:48 ` Jiri Olsa
2025-10-31 1:37 ` Josh Poimboeuf
2025-10-27 22:25 ` Jiri Olsa
2025-10-27 13:13 ` [PATCH 2/3] x86/fgraph,bpf: Fix stack ORC unwind from kprobe_multi return probe Jiri Olsa
2025-10-28 7:02 ` Masami Hiramatsu
2025-10-27 13:13 ` [PATCH 3/3] selftests/bpf: Add stacktrace ips test for kprobe_multi/kretprobe_multi Jiri Olsa
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