From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-43416: powerpc, perf: Check that current->mm is alive before getting user callchain
Date: Fri, 8 May 2026 16:22:25 +0200 [thread overview]
Message-ID: <2026050845-CVE-2026-43416-8fb1@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
powerpc, perf: Check that current->mm is alive before getting user callchain
It may happen that mm is already released, which leads to kernel panic.
This adds the NULL check for current->mm, similarly to
commit 20afc60f892d ("x86, perf: Check that current->mm is alive before getting user callchain").
I was getting this panic when running a profiling BPF program
(profile.py from bcc-tools):
[26215.051935] Kernel attempted to read user page (588) - exploit attempt? (uid: 0)
[26215.051950] BUG: Kernel NULL pointer dereference on read at 0x00000588
[26215.051952] Faulting instruction address: 0xc00000000020fac0
[26215.051957] Oops: Kernel access of bad area, sig: 11 [#1]
[...]
[26215.052049] Call Trace:
[26215.052050] [c000000061da6d30] [c00000000020fc10] perf_callchain_user_64+0x2d0/0x490 (unreliable)
[26215.052054] [c000000061da6dc0] [c00000000020f92c] perf_callchain_user+0x1c/0x30
[26215.052057] [c000000061da6de0] [c0000000005ab2a0] get_perf_callchain+0x100/0x360
[26215.052063] [c000000061da6e70] [c000000000573bc8] bpf_get_stackid+0x88/0xf0
[26215.052067] [c000000061da6ea0] [c008000000042258] bpf_prog_16d4ab9ab662f669_do_perf_event+0xf8/0x274
[...]
In addition, move storing the top-level stack entry to generic
perf_callchain_user to make sure the top-evel entry is always captured,
even if current->mm is NULL.
[Maddy: fixed message to avoid checkpatch format style error]
The Linux kernel CVE team has assigned CVE-2026-43416 to this issue.
Affected and fixed versions
===========================
Issue introduced in 2.6.32 with commit 20002ded4d937ca87aca6253b874920a96a763c4 and fixed in 6.18.19 with commit 98074e16742ae87fb82e234b419783c5ffc9baea
Issue introduced in 2.6.32 with commit 20002ded4d937ca87aca6253b874920a96a763c4 and fixed in 6.19.9 with commit 7e5f60b8cfc02a2b23a40a5f5fd2fa81d010e737
Issue introduced in 2.6.32 with commit 20002ded4d937ca87aca6253b874920a96a763c4 and fixed in 7.0 with commit e9bbfb4bfa86c6b5515b868d6982ac60505d7e39
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2026-43416
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
arch/powerpc/perf/callchain.c
arch/powerpc/perf/callchain_32.c
arch/powerpc/perf/callchain_64.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/98074e16742ae87fb82e234b419783c5ffc9baea
https://git.kernel.org/stable/c/7e5f60b8cfc02a2b23a40a5f5fd2fa81d010e737
https://git.kernel.org/stable/c/e9bbfb4bfa86c6b5515b868d6982ac60505d7e39
reply other threads:[~2026-05-08 14:24 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
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=2026050845-CVE-2026-43416-8fb1@gregkh \
--to=gregkh@linuxfoundation.org \
--cc=cve@kernel.org \
--cc=gregkh@kernel.org \
--cc=linux-cve-announce@vger.kernel.org \
--cc=linux-kernel@vger.kernel.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