From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794064785; b=r9ZXFVf6Nv8+yKYrfbD2voshqeLhO9f0FpjMpmr6eNZuva0BvmW6eB6RP4ig6I41ACzv m7QEROiRnXWXNhgn7AmuXtR8N0y1a0uaIWqpJA2zJU6boNJagklFLpxtF30bIOiQTshDt p8cZy9/ObcjEmCSP9UuithUJGl13Z8qzWzRRvay6TFydenziG6/XK/Hl3Ew8QKHarNoY0 0Lx7Be+Dvs41Mhz8KNcfjxZU74B5VNfaUE0cEJCsTcEWSkUnAj9pUsf2BGFZgpKa7ad0o QC8sePs4DnufwAQoB9rml0DTd5TFS7BAwkiW9sloMMaY7cgz9yVdne6LvM/XPNr/orA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794064785; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=NL9lkRo/Q5LGZcGFJ/LCV7nfWY+uNpi4e+HXBopJUMU=; b=ZN3I8X0dgw1z5kjEp3Jlxr6lZDDJwUwHAB+Lvg1Ym5Az22uXeC8QVEBwA8lmA5S5vjrv Dh/jR8p/+zasiO8oNPCVZeObdbCXgkyKpME0WupLGeLtBAQA06tMaAlQPbgjJrhTQJSze iROQ+hqEAMpqMIshpcN2Wf1QQyQ2kDOzaa3nCI2+our1cyditBrIJ6xG9mL+4Xx86CNn+ zCB4LmCSJMgblsB7BlXWu2zxRGF0j/aSpckBCBoFj2z79neJ/FfAIZyB/6MosA7Rnsx76 JyRWOSqDsGCzIZ0/7zzpMsyrFe16A1rtS5IZIYaPZXk8yStI856tf2Hqb5E/FQMT0PQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=mYx9Xie4; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E65BC606A9FA; Sat, 7 Nov 2026 15:19:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=mYx9Xie4 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9B1151F0089F; Sat, 7 Nov 2026 15:19:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794064784; bh=NL9lkRo/Q5LGZcGFJ/LCV7nfWY+uNpi4e+HXBopJUMU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mYx9Xie4IYdEeuuj/f9Ma7owNPi9ZpIv9pBvmcSBPFfZJmq10JxIMwBtOxRo311jp St7X7myjtxBavj7xow51dQNG9aPHIj2xrUvc5BAfPZZBDm7AVVkQ15oHoHEtwz0tIu NN6ezsgEJUKdqcgYScMkvnvF/VO/fs2d9Ij/q0lQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bradley Morgan , Andrew Morton , Petr Mladek , Guenetr Roeck , Sashiko , Wang Jinchao , Wim Van Sebroeck , Sasha Levin Subject: [PATCH 7.3 0733/1257] panic: fix va_list reuse in panic_try_force_cpu() Date: Sat, 7 Nov 2026 08:50:29 -0500 Message-ID: <20261107134959.520521612@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134939.434104957@linuxfoundation.org> References: <20261107134939.434104957@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bradley Morgan [ Upstream commit 245001a347f1effc09c233d1712e1efeedab59ee ] 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: Signed-off-by: Sasha Levin --- kernel/panic.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/kernel/panic.c b/kernel/panic.c index e1b443150ba0b..6b5728c3c9ce2 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -417,7 +417,12 @@ static bool panic_try_force_cpu(const char *fmt, va_list args) * 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)"; -- 2.53.0