From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 00F0A46F4A3; Wed, 16 Sep 2026 20:45:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789591558; cv=none; b=cy/2QnFVWNaBa1Ee53uolbyeS4HEmnSOoHSEojjXcoAnkpYAh0xl+uts5lU5JLkBKFaXB79Crxk2XRX/1clMLB8yHysmwubvWMjwOe69KycuTedG9z4LnUjQjq1mzxrP61fG9wp9te805FetGXJ6gv1K2eYa2FnvYe7v0Qxw+1U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789591558; c=relaxed/simple; bh=5ZckBG32fcXZ3WoQYmLUyc2UPA+dLuWeSx/4die7qO0=; h=Date:To:From:Subject:Message-Id; b=jnQtOy2s5y/p25DS5SnYn0nuF0f/uhrB7Aow0IO9oH6lbDvXijE1J4jW4xA5bvFqkG4cnA2S4iBwSoC85X9wzF4KVgJoiJ2nguO+qcGBWSOjzaOeFHInmLCgBroexMsO9FBYniAy7UveImelpQgQR788BxXN/w3mDXDtBZDw6A8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=bxsw6aBK; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="bxsw6aBK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A9ACE1F00898; Wed, 16 Sep 2026 20:45:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789591541; bh=Gq81EsN1ivRYB8+wqReGGnuPIT6fNkq7Jtao2oFBb8I=; h=Date:To:From:Subject; b=bxsw6aBKD0fmAck/trRk201nXyudJsZjkXKxWoXJ/MUsZnPEdveCneiUOBeQDCD9q YWo/IOB27920q7/eG8QPwMAoKzh2cRbAiliBjdF6+J7sJHRNsFs7PrxO8OM2WNEL6k bx5p0/pDnOVXZQ2qXh5R5jSwBLuZkjudR1t77+Vc= Date: Wed, 16 Sep 2026 13:45:41 -0700 To: mm-commits@vger.kernel.org,wim@linux-watchdog.org,wangjinchao600@gmail.com,stable@vger.kernel.org,sashiko-bot@kernel.org,pmladek@suse.com,linux@roeck-us.net,brads@mainlining.org,akpm@linux-foundation.org From: Andrew Morton Subject: + panic-fix-va_list-reuse-in-panic_try_force_cpu.patch added to mm-nonmm-unstable branch Message-Id: <20260916204541.A9ACE1F00898@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: panic: fix va_list reuse in panic_try_force_cpu() has been added to the -mm mm-nonmm-unstable branch. Its filename is panic-fix-va_list-reuse-in-panic_try_force_cpu.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/panic-fix-va_list-reuse-in-panic_try_force_cpu.patch This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Bradley Morgan Subject: panic: fix va_list reuse in panic_try_force_cpu() Date: Wed, 16 Sep 2026 18:29:54 +0000 vsnprintf() consumes the caller's va_list. When the redirect fails, vpanic() reuses it for the panic message, which is undefined behavior. Use va_copy(). Link: https://lore.kernel.org/20260916182957.7788-4-brads@mainlining.org Fixes: 2e171ab29f91 ("panic: add panic_force_cpu= parameter to redirect panic to a specific CPU") Signed-off-by: Bradley Morgan Signed-off-by: Andrew Morton Reviewed-by: Petr Mladek Cc: Guenetr Roeck Cc: Sashiko Cc: Wang Jinchao Cc: Wim Van Sebroeck Cc: --- kernel/panic.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/kernel/panic.c~panic-fix-va_list-reuse-in-panic_try_force_cpu +++ a/kernel/panic.c @@ -417,7 +417,12 @@ static bool panic_try_force_cpu(const ch * fall back to static message for early boot panics or allocation failure. */ if (panic_force_buf) { - vsnprintf(panic_force_buf, PANIC_MSG_BUFSZ, fmt, args); + va_list ap; + + /* Do not consume args, the caller reuses it if we fail */ + va_copy(ap, args); + vsnprintf(panic_force_buf, PANIC_MSG_BUFSZ, fmt, ap); + va_end(ap); msg = panic_force_buf; } else { msg = "Redirected panic (buffer unavailable)"; _ Patches currently in -mm which might be from brads@mainlining.org are taskstats-copy-signal-stats-under-siglock-in-taskstats_exit.patch mailmap-update-email-address-for-bradley-morgan.patch taskstats-drop-the-unused-cpu_dont_care-enum-member.patch panic-fix-redirect-cpu-race-in-panic_try_force_cpu.patch panic-flatten-nmi_panic-control-flow.patch panic-fix-va_list-reuse-in-panic_try_force_cpu.patch panic-restore-variable-arguments-to-nmi_panic.patch panic-allow-force_cpu-redirect-from-an-nmi.patch panic-kill-the-buffer-unavailable-redirect-fallback.patch