[Crash-utility] Crash-utility Digest, Vol 190, Issue 20

[lijiang]

>
>     On 7/28/21, 11:14 AM, "crash-utility-bounces at redhat.com on behalf of
> David Wysochanski" <crash-utility-bounces at redhat.com on behalf of
> dwysocha at redhat.com> wrote:
>
>         On Wed, Apr 28, 2021 at 8:54 AM lijiang <lijiang at redhat.com>
> wrote:
>         >
>         > ? 2021?04?26? 19:17, crash-utility-request at redhat.com ??:
>         > > Message: 3
>         > > Date: Mon, 26 Apr 2021 11:27:40 +0300
>         > > From: Vasily Averin <vvs at virtuozzo.com>
>         > > To: crash-utility at redhat.com
>         > > Subject: [Crash-utility] crash does not work with last fedora
> kernels?
>         > > Message-ID: <
> 8f8782a9-3da6-5d3c-c509-8b8ec8a30957 at virtuozzo.com>
>         > > Content-Type: text/plain; charset=utf-8
>         > >
>         > > It looks like Fedora kernels uses gcc11 and generates
> debuginfo in DWARF 5 format.
>         > >
>         > > [root at localhost ~]# rpm -q crash
>         > > crash-7.2.9-5.fc35.x86_64
>         > > [root at localhost ~]# uname -a
>         > > Linux localhost.localdomain 5.11.12-300.fc34.x86_64 #1 SMP Wed
> Apr 7 16:31:13 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
>         > >
>         > >
>         > > [root at localhost ~]# crash -1
>         > > Dwarf Error: wrong version in compilation unit header (is 5,
> should be 2, 3, or 4) [in module
> /usr/lib/debug/usr/lib/modules/5.11.12-300.fc34.x86_64/vmlinux]
>         > > crash: gdb_session_init: pulling in debug data by accessing
> init_mm.mmap
>         > > Dwarf Error: wrong version in compilation unit header (is 5,
> should be 2, 3, or 4) [in module
> /usr/lib/debug/usr/lib/modules/5.11.12-300.fc34.x86_64/vmlinux]
>         > >
>         > > crash:
> /usr/lib/debug/lib/modules/5.11.12-300.fc34.x86_64/vmlinux: no debugging
> data available
>         > >
>         > > [root at localhost ~]# ls -al
> /usr/lib/debug/lib/modules/5.11.12-300.fc34.x86_64/vmlinux
>         > > -rwxr-xr-x. 1 root root 679679112 Apr  7 20:14
> /usr/lib/debug/lib/modules/5.11.12-300.fc34.x86_64/vmlinux
>         > > [root at localhost ~]# rpm -qf
> /usr/lib/debug/lib/modules/5.11.12-300.fc34.x86_64/vmlinux
>         > > kernel-debuginfo-5.11.12-300.fc34.x86_64
>         > >
>         > > NB: last fc35 does not work too.
>         > >
>         >
>         > Thank you for reporting this issue, Vasily.
>         >
>         > The DWARF-5 caused this failure. I will have a look and try to
> handle this issue later.
>         >
>         > Thanks.
>         > Lianbo
>         >
>
>         What's the status of this issue?  Is this due to needing updated
>         embedded gdb or something else?
>

Hi, David
Thank you for the attention.
Currently, Fedora kernel has been forced to generate the DWARF4 debuginfo via
the
CONFIG_DEBUG_INFO_DWARF4 kernel option, see jforbes' comment:
https://src.fedoraproject.org/rpms/kernel/pull-request/48

Once crash gdb is upgraded, the DWARF5 could be enabled again in Fedora
kernel.

BTW: that is a temporary branch, still under tests and it has not been
announced yet.

Thanks.
Lianbo
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