From: Ivan Babrou <ivan@cloudflare.com>
To: Russell King <russell.king@oracle.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Alan Maguire <alan.maguire@oracle.com>,
kernel-team <kernel-team@cloudflare.com>,
bpf <bpf@vger.kernel.org>,
linux-perf-users@vger.kernel.org
Subject: Removal of 128MB limit for BPF JIT programs broke perf symbolication on aarch64
Date: Mon, 18 Jul 2022 09:25:18 -0700 [thread overview]
Message-ID: <CABWYdi2NBSv8sUdFONrYyACa60+W6O3+r5D44OXjftxPySKTXQ@mail.gmail.com> (raw)
Hello,
We noticed that perf symbolication is broken on aarch64:
ivan@vm:~$ sudo perf_5.10 record -e cpu-clock --cpu 3 -g --call-graph
dwarf -F 11 -- sleep 0.1
ivan@vm:~$ sudo perf_5.10 script
swapper 0 [003] 75.516009: 90909090 cpu-clock:
ffffffe7fe311808 [unknown] ([unknown])
ffffffe7fdaf0a60 [unknown] ([unknown])
ffffffe7fdaf0bdc [unknown] ([unknown])
ffffffe7fda29538 [unknown] ([unknown])
ffffffe7fe3253b8 [unknown] ([unknown])
On Linux 5.15 I was able to bisect this to 5.15.18, where this commit
was responsible (b89ddf4cca43 upstream):
* 9c82ce593626 arm64/bpf: Remove 128MB limit for BPF JIT programs
Reverting this commit in 5.15.18 resolves the issue. The issue is also
present in 5.19-rc6.
In addition to that, I noticed that on my personal kernel build this
doesn't happen on any kernel version. After many attempts at config
reconciliation, I narrowed it down to CONFIG_PROC_KCORE. When the
option is enabled and the commit b89ddf4cca43 is present, the stacks
have no kernel symbols.
This seems like a regression.
next reply other threads:[~2022-07-18 16:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-18 16:25 Ivan Babrou [this message]
2022-07-18 18:33 ` [External] : Removal of 128MB limit for BPF JIT programs broke perf symbolication on aarch64 Russell King
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