From: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Kim Phillips <kim.phillips@amd.com>,
Michael Petlan <mpetlan@redhat.com>,
Namhyung Kim <namhyung@kernel.org>,
Ravi Bangoria <ravi.bangoria@linux.ibm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] perf symbols: Don't try to find a vmlinux file when looking for kernel modules
Date: Mon, 2 Mar 2020 17:21:01 -0300 [thread overview]
Message-ID: <20200302202101.GE10335@kernel.org> (raw)
In-Reply-To: <20200302200249.GA9761@krava>
Em Mon, Mar 02, 2020 at 09:02:49PM +0100, Jiri Olsa escreveu:
> On Mon, Mar 02, 2020 at 04:10:07PM -0300, Arnaldo Carvalho de Melo wrote:
> > The dso->kernel value is now set to everything that is in
> > machine->kmaps, but that was being used to decide if vmlinux lookup is
> > needed, which ended up making that lookup be made for kernel modules,
> > that now have dso->kernel set, leading to these kinds of warnings when
> > running on a machine with compressed kernel modules, like fedora:31:
> >
> > [root@five ~]# perf record -F 10000 -a sleep 2
> > [ perf record: Woken up 1 times to write data ]
> > lzma: fopen failed on vmlinux: 'No such file or directory'
> > lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
> > lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
> > lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
> > lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
> > lzma: fopen failed on vmlinux: 'No such file or directory'
> > lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
> > lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
> > lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
> > lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
> > lzma: fopen failed on vmlinux: 'No such file or directory'
> > lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
> > lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
> > lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
> > lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
> > lzma: fopen failed on vmlinux: 'No such file or directory'
> > lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
> > lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
> > lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
> > lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
> > lzma: fopen failed on vmlinux: 'No such file or directory'
> > lzma: fopen failed on /boot/vmlinux: 'No such file or directory'
> > lzma: fopen failed on /boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
> > lzma: fopen failed on /usr/lib/debug/boot/vmlinux-5.5.5-200.fc31.x86_64: 'No such file or directory'
> > lzma: fopen failed on /lib/modules/5.5.5-200.fc31.x86_64/build/vmlinux: 'No such file or directory'
> > [ perf record: Captured and wrote 1.024 MB perf.data (1366 samples) ]
> > [root@five ~]#
> >
> > This happens when collecting the buildid, when we find samples for
> > kernel modules, fix it by checking if the looked up DSO is a kernel
> > module by other means.
> >
> > Fixes: 02213cec64bb ("perf maps: Mark module DSOs with kernel type")
>
> ok, I couldn't see that because kcore took over the modules,
> for some reason you don't have it enabled on your system?
Humm, maybe you don't have a reachable vmlinux so it ends up using
/proc/kcore? I even think we should make the default... :-)
> because I had to disable it manualy in the code.. I think
> we should add some --no-kcore option for record
>
> the fix is working for me:
>
> Tested/Acked-by: Jiri Olsa <jolsa@redhat.com>
Thanks, for checking!
> thanks,
> jirka
>
--
- Arnaldo
next prev parent reply other threads:[~2020-03-02 20:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-02 19:10 [PATCH] perf symbols: Don't try to find a vmlinux file when looking for kernel modules Arnaldo Carvalho de Melo
2020-03-02 19:20 ` Jiri Olsa
2020-03-02 20:02 ` Jiri Olsa
2020-03-02 20:21 ` Arnaldo Carvalho de Melo [this message]
2020-03-04 11:01 ` [tip: perf/urgent] " tip-bot2 for Arnaldo Carvalho de Melo
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