From: Petr Mladek <pmladek@suse.com>
To: Stephen Boyd <swboyd@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, Jiri Olsa <jolsa@kernel.org>,
Alexei Starovoitov <ast@kernel.org>, Jessica Yu <jeyu@kernel.org>,
Evan Green <evgreen@chromium.org>,
Hsin-Yi Wang <hsinyi@chromium.org>,
Steven Rostedt <rostedt@goodmis.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v3 03/12] dump_stack: Add vmlinux build ID to stack traces
Date: Thu, 8 Apr 2021 12:13:20 +0200 [thread overview]
Message-ID: <YG7XQK1FCofMZsqM@alley> (raw)
In-Reply-To: <161786283299.3790633.9395579294249054249@swboyd.mtv.corp.google.com>
On Wed 2021-04-07 23:20:32, Stephen Boyd wrote:
> Quoting Petr Mladek (2021-04-07 07:03:19)
> > # readelf -Wn vmlinux-5.12.0-rc6-default+
> >
> > Displaying notes found in: .notes
> > Owner Data size Description
> > Xen 0x00000006 Unknown note type: (0x00000006) description data: 6c 69 6e 75 78 00
> > Xen 0x00000004 Unknown note type: (0x00000007) description data: 32 2e 36 00
> > Xen 0x00000008 Unknown note type: (0x00000005) description data: 78 65 6e 2d 33 2e 30 00
> > Xen 0x00000008 Unknown note type: (0x00000003) description data: 00 00 00 ffffff80 ffffffff ffffffff ffffffff ffffffff
> >
>
> Thanks for the readelf output. That was most helpful to see what's going
> on. The buildid code isn't prepared for this it seems. We'll need to
> check the note data to see if it starts with "GNU\0" and if it does then
> we use it as the buildid. I'm not sure what this Xen note is that has a
> type of 3 but I think that's OK, it won't have "GNU" in there so we
> should ignore it. Does this patch work?
>
> ----8<----
> diff --git a/lib/buildid.c b/lib/buildid.c
> index 483abf71eeec..f281dbe6fb83 100644
> --- a/lib/buildid.c
> +++ b/lib/buildid.c
> @@ -25,6 +25,7 @@ static int parse_build_id_buf(unsigned char *build_id,
>
> if (nhdr->n_type == BUILD_ID &&
> nhdr->n_namesz == sizeof("GNU") &&
> + !strcmp((char *)(nhdr + 1), "GNU") &&
> nhdr->n_descsz > 0 &&
> nhdr->n_descsz <= BUILD_ID_SIZE_MAX) {
> memcpy(build_id,
It helped with the vmlinux buildid. I see the following:
[ 551.435942][ T1803] test_printf: loaded.
[ 551.436667][ T1803] ------------[ cut here ]------------
[ 551.437561][ T1803] kernel BUG at lib/test_printf.c:689!
[ 551.438352][ T1803] invalid opcode: 0000 [#1] SMP NOPTI
[ 551.438359][ T1803] CPU: 3 PID: 1803 Comm: modprobe Kdump: loaded Tainted: G E 5.12.0-rc6-default+ #176 e51781e52aaf4d6dfea7a18574c104c8bfd7c37f
[ 551.438363][ T1803] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014
[ 551.438365][ T1803] RIP: 0010:test_printf_init+0x561/0xc99 [test_printf c2388ff0552611501b4d2ad58d8e5ca441d9a350]
[ 551.443090][ T1803] Code: 00 48 c7 c7 b8 36 1b c0 e8 19 f9 ff ff b9 ab 00 00 00 48 c7 c2 93 36 1b c0 be 08 00 00 00 48 c7 c7 af 36 1b c0 e8 fc f8 ff ff <0f> 0b 8b 05 44 07 00 00 8b 35 3a 07 00 00 8b 1d 3c 07 00 00 85 c0
[ 551.443094][ T1803] RSP: 0018:ffffb62c0039bc78 EFLAGS: 00010282
[ 551.443096][ T1803] RAX: 0000000000000000 RBX: ffffb62c0039bc80 RCX: ffffd62bffc00b70
[ 551.443098][ T1803] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffa0352fd5
[ 551.443099][ T1803] RBP: ffffffffc01b7367 R08: 0000000000000001 R09: 0000000000000001
[ 551.443100][ T1803] R10: 0000000000000000 R11: 0000000000000001 R12: ffff9bc08c87c820
[ 551.443101][ T1803] R13: 0000000000000001 R14: ffff9bc0d2798480 R15: ffffb62c0039be90
[ 551.443102][ T1803] FS: 00007f5767485b80(0000) GS:ffff9bc0ffc00000(0000) knlGS:0000000000000000
[ 551.443103][ T1803] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 551.443105][ T1803] CR2: 00007f5766b36ef0 CR3: 0000000100368004 CR4: 0000000000370ee0
[ 551.443108][ T1803] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 551.443108][ T1803] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 551.443109][ T1803] Call Trace:
[ 551.443113][ T1803] ? __test+0x13c/0x149 [test_printf]
[ 551.443116][ T1803] ? rcu_read_lock_sched_held+0x52/0x80
[ 551.443120][ T1803] do_one_initcall+0x5b/0x2d0
[ 551.443125][ T1803] do_init_module+0x5b/0x21c
[ 551.443127][ T1803] load_module+0x1eaa/0x23c0
[ 551.443130][ T1803] ? show_modinfo_version+0x30/0x30
[ 551.443134][ T1803] ? __do_sys_finit_module+0xad/0x110
[ 551.443135][ T1803] __do_sys_finit_module+0xad/0x110
[ 551.443138][ T1803] do_syscall_64+0x33/0x40
[ 551.443139][ T1803] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 551.443143][ T1803] RIP: 0033:0x7f5766b5b2a9
[
Note that it still does not show the build id for the module. It fails
in the module init call and the build id should be already initialized
at this stage.
One more thing. I am not familiar with the elf-related code.
Is it safe to access (nhdr + 1)? Do we need a check that
it is still withing the given section?
Best Regards,
Petr
next prev parent reply other threads:[~2021-04-08 10:13 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-31 3:05 [PATCH v3 00/12] Add build ID to stacktraces Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 01/12] buildid: Add API to parse build ID out of buffer Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 02/12] buildid: Stash away kernels build ID on init Stephen Boyd
2021-04-08 12:05 ` Jessica Yu
2021-04-08 18:52 ` Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 03/12] dump_stack: Add vmlinux build ID to stack traces Stephen Boyd
2021-04-07 13:42 ` Petr Mladek
2021-04-08 5:44 ` Stephen Boyd
2021-04-07 14:03 ` Petr Mladek
2021-04-08 1:14 ` Stephen Boyd
2021-04-08 6:20 ` Stephen Boyd
2021-04-08 10:13 ` Petr Mladek [this message]
2021-04-08 19:52 ` Stephen Boyd
2021-04-08 21:08 ` Stephen Boyd
2021-04-09 9:19 ` Petr Mladek
2021-03-31 3:05 ` [PATCH v3 04/12] module: Add printk format to add module build ID to stacktraces Stephen Boyd
2021-04-07 14:54 ` Petr Mladek
2021-04-07 15:07 ` Andy Shevchenko
2021-04-07 15:03 ` Petr Mladek
2021-04-07 15:37 ` Andy Shevchenko
2021-04-08 6:58 ` Stephen Boyd
2021-04-08 13:44 ` Jessica Yu
2021-04-08 14:05 ` Andy Shevchenko
2021-04-08 19:57 ` Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 05/12] arm64: stacktrace: Use %pSb for backtrace printing Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 06/12] x86/dumpstack: " Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 07/12] scripts/decode_stacktrace.sh: Support debuginfod Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 08/12] scripts/decode_stacktrace.sh: Silence stderr messages from addr2line/nm Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 09/12] scripts/decode_stacktrace.sh: Indicate 'auto' can be used for base path Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 10/12] buildid: Mark some arguments const Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 11/12] buildid: Fix kernel-doc notation Stephen Boyd
2021-03-31 3:05 ` [PATCH v3 12/12] kdump: Use vmlinux_build_id to simplify Stephen Boyd
2021-04-07 17:03 ` Petr Mladek
2021-04-08 5:36 ` Stephen Boyd
2021-04-08 10:17 ` Baoquan He
2021-04-08 19:58 ` Stephen Boyd
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YG7XQK1FCofMZsqM@alley \
--to=pmladek@suse.com \
--cc=akpm@linux-foundation.org \
--cc=andriy.shevchenko@linux.intel.com \
--cc=ast@kernel.org \
--cc=evgreen@chromium.org \
--cc=hsinyi@chromium.org \
--cc=jeyu@kernel.org \
--cc=jolsa@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=swboyd@chromium.org \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).