From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D71923EFD2D for ; Fri, 8 May 2026 14:24:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778250287; cv=none; b=RsxR3hRb0SVA/GEAQfOJAX7kvTuc9GfOYKwMnsQNDV+kDX/crRdcVbvpM6i+IhCZFISTAjUCEYyR8XZmGhJ7Y2VdHoDz4RY46utd0z/EMBF0GyrriyOg4W0Zpv2o7tvgTSq08A0XaDDI78rTQMvxX8v5Vdj0XVadDnGywidVzFA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778250287; c=relaxed/simple; bh=yMzU7W52Pl46YrkBwfDp6xrkUxLlh2u3omRfuJYxM8I=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=UBk9ZtDotIKt3XN1iq6e8Ee4SN3XrTu3z5EiVxLfH4V7R/8npqS2r9G+Kg1bTRmbcFjoDaxE7nJU6t+urizDqn9i7PSY36xA7o0o0Yx7pv936M5JGxxynAoCaAUzf1k0T01DqhV9WyhRd2hT1M4v6JBlrXZIAxsVT8RSWrNiFwY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=De7hbuWI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="De7hbuWI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63715C2BCB0; Fri, 8 May 2026 14:24:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778250287; bh=yMzU7W52Pl46YrkBwfDp6xrkUxLlh2u3omRfuJYxM8I=; h=From:To:Cc:Subject:Date:Reply-To:From; b=De7hbuWINv/QpphOUkfwEsQofZltyMGGV7KQE7friRZYJhZ+6tMEN5yV0DUzVB3aw Z5H10rmoajcXs4GVARbfxrdM+MzQqIHO8nFfuVGqi4l3ZkoStzqlyMqJNzQEQdp7yg w6dnVtG0fO83APbvoHjB+4SaPnLC5IuI7hf3gAZM= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman 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 Message-ID: <2026050845-CVE-2026-43416-8fb1@gregkh> X-Mailer: git-send-email 2.54.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3483; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=9CwEy18ZxsQAjPVtDIc4nmzrvlbFjMFxdgJzk+5oqL8=; b=owGbwMvMwCRo6H6F97bub03G02pJDJl/P1Za/FlwiHelY0S9x9/Aewfjgg7sX/B0X/5Xaf9LX 14deOc4uyOWhUGQiUFWTJHlyzaeo/srDil6GdqehpnDygQyhIGLUwAmcvwww1yBNG6RY+mL5sy7 IvZ022lHefFHLUEM89O8V92yU5Hq+ppVear2R7HI1J+zagE= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman 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