linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Thorsten Leemhuis <regressions@leemhuis.info>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: "regressions@lists.linux.dev" <regressions@lists.linux.dev>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Chris Kennelly <ckennelly@google.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Song Liu <songliubraving@fb.com>,
	David Rientjes <rientjes@google.com>,
	Ian Rogers <irogers@google.com>, Hugh Dickins <hughd@google.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Sandeep Patil <sspatil@google.com>,
	Fangrui Song <maskray@google.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Shuah Khan <shuah@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Bug 215734 - shared object loaded very low in memory ARM 32bit with kernel 5.17.0
Date: Thu, 31 Mar 2022 08:17:30 +0200	[thread overview]
Message-ID: <e2b90c55-1a4a-4cf1-2dc7-2b2a4dc7d168@leemhuis.info> (raw)

Hi, this is your Linux kernel regression tracker.

I noticed a regression report in bugzilla.kernel.org that afaics nobody
acted upon since it was reported about a week ago, that's why I decided
to forward it to the lists and all people that seemed to be relevant
here. Note, this is the second regression report referencin a commit
from H.J. Lu as culprit (9630f0d60fec ("fs/binfmt_elf: use PT_LOAD
p_align values for static PIE")). I forwarded the first one on Monday
already, but seems nothing happened:
https://lore.kernel.org/all/cb5b81bd-9882-e5dc-cd22-54bdbaaefbbc@leemhuis.info/

Anyway, to get back to the latest report. To quote from
https://bugzilla.kernel.org/show_bug.cgi?id=215734 :

>  Jan Palus 2022-03-24 10:17:02 UTC
> 
> This is a followup to https://sourceware.org/bugzilla/show_bug.cgi?id=28990 where ld.so --verify segfault was reported on binaries > 4MB.
> 
> It appears that starting with kernel 5.17.0 shared object is loaded in the begging of address space at least on 32-bit ARM:
> 
> /proc/<pid>/maps just before mmap (5.17):
> 00400000-00429000 r-xp 00000000 b3:02 393320     /lib/ld-linux-armhf.so.3
> 00439000-0043c000 rw-p 00029000 b3:02 393320     /lib/ld-linux-armhf.so.3
> 76ffd000-76ffe000 r-xp 00000000 00:00 0          [sigpage]
> 76ffe000-76fff000 r--p 00000000 00:00 0          [vvar]
> 76fff000-77000000 r-xp 00000000 00:00 0          [vdso]
> 7efdf000-7f000000 rw-p 00000000 00:00 0          [stack]
> ffff0000-ffff1000 r-xp 00000000 00:00 0          [vectors]
> 
> causing segfaults when mmaping large binaries at fixed address 0x10000 (ie done by ld.so --verify used by ldd).
> 
> By comparison it is not the case for kernel 5.16.8:
> 
> /proc/<pid>/maps just before mmap (5.16):
> 76fc4000-76fed000 r-xp 00000000 b3:02 393320     /lib/ld-linux-armhf.so.3
> 76ffa000-76ffb000 r-xp 00000000 00:00 0          [sigpage]
> 76ffb000-76ffc000 r--p 00000000 00:00 0          [vvar]
> 76ffc000-76ffd000 r-xp 00000000 00:00 0          [vdso]
> 76ffd000-77000000 rw-p 00029000 b3:02 393320     /lib/ld-linux-armhf.so.3
> 7efdf000-7f000000 rw-p 00000000 00:00 0          [stack]
> ffff0000-ffff1000 r-xp 00000000 00:00 0          [vectors]
> 
> [reply] [−] Comment 1 Jan Palus 2022-03-29 22:14:12 UTC
> 
> First bad commit appears to be:
> 
> From: "H.J. Lu" <hjl.tools@gmail.com>
> Date: Wed, 19 Jan 2022 18:09:40 -0800
> Subject: fs/binfmt_elf: use PT_LOAD p_align values for static PIE
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9630f0d60fec5fbcaa4435a66f75df1dc9704b66
> 

Could somebody take a look into this? Or was this discussed somewhere
else already? Or even fixed?


Anyway, to get this tracked:

#regzbot introduced: 9630f0d60fec5fbcaa4435a66f75df1dc9704b6
#regzbot from: Jan Palus <jpalus@fastmail.com>
#regzbot title: shared object loaded very low in memory ARM 32bit
causing segfaults on binaries > 4MB
#regzbot link: https://bugzilla.kernel.org/show_bug.cgi?id=215734

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)

P.S.: As the Linux kernel's regression tracker I'm getting a lot of
reports on my table. I can only look briefly into most of them and lack
knowledge about most of the areas they concern. I thus unfortunately
will sometimes get things wrong or miss something important. I hope
that's not the case here; if you think it is, don't hesitate to tell me
in a public reply, it's in everyone's interest to set the public record
straight.

-- 
Additional information about regzbot:

If you want to know more about regzbot, check out its web-interface, the
getting start guide, and the references documentation:

https://linux-regtracking.leemhuis.info/regzbot/
https://gitlab.com/knurd42/regzbot/-/blob/main/docs/getting_started.md
https://gitlab.com/knurd42/regzbot/-/blob/main/docs/reference.md

The last two documents will explain how you can interact with regzbot
yourself if your want to.

Hint for reporters: when reporting a regression it's in your interest to
CC the regression list and tell regzbot about the issue, as that ensures
the regression makes it onto the radar of the Linux kernel's regression
tracker -- that's in your interest, as it ensures your report won't fall
through the cracks unnoticed.

Hint for developers: you normally don't need to care about regzbot once
it's involved. Fix the issue as you normally would, just remember to
include 'Link:' tag in the patch descriptions pointing to all reports
about the issue. This has been expected from developers even before
regzbot showed up for reasons explained in
'Documentation/process/submitting-patches.rst' and
'Documentation/process/5.Posting.rst'.

             reply	other threads:[~2022-03-31  6:17 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-31  6:17 Thorsten Leemhuis [this message]
2022-04-09 11:52 ` Bug 215734 - shared object loaded very low in memory ARM 32bit with kernel 5.17.0 Thorsten Leemhuis
2022-04-09 22:17   ` Andrew Morton
2022-04-16  4:42 ` Bug 215734 - shared object loaded very low in memory ARM 32bit with kernel 5.17.0 #forregzbot Thorsten Leemhuis

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=e2b90c55-1a4a-4cf1-2dc7-2b2a4dc7d168@leemhuis.info \
    --to=regressions@leemhuis.info \
    --cc=adobriyan@gmail.com \
    --cc=akpm@linux-foundation.org \
    --cc=ckennelly@google.com \
    --cc=hjl.tools@gmail.com \
    --cc=hughd@google.com \
    --cc=irogers@google.com \
    --cc=kirill.shutemov@linux.intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=maskray@google.com \
    --cc=mike.kravetz@oracle.com \
    --cc=ndesaulniers@google.com \
    --cc=regressions@lists.linux.dev \
    --cc=rientjes@google.com \
    --cc=shuah@kernel.org \
    --cc=songliubraving@fb.com \
    --cc=sspatil@google.com \
    --cc=surenb@google.com \
    --cc=viro@zeniv.linux.org.uk \
    /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).