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=1794410683; b=qiWb83tLruFunsVRKxu8wu8b8YUniqlTsTaATP+MVfIz75BexmMYLmwA6LQyacmCbSXZ EJh4A0BNvKQET1P5fuRlfcd4Y224sUm5qZed0Tz9HzVntSsh6dt0uSHPPVst0uIyISnyc P+dvkXfJcGgV5TqS8sqwb40CSzobKB11DmedrNXThOa3NiplZiwdtQxgo06iea5mat89i +21QFTr9fMcnGJbL4xmCDLdey+nkyoNatl2djygLN1DwUS0i/9mqERY2/s9TbCVI0GAlB iUjqy6LcaEuNmyjlTYkgINoTdv5SVgh8XEkKrAoItpPywFpXawz2iqHFSOccHuyzFDw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794410683; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=YiGFuS54+M9xVjICHulOyYObpz+KXxAGRy2R5hyjO90=; b=oAGXfiTL/z47mo8oh8CGtQMi6o34K1P/9xT4inVl8GdP+p0KP3o12IHe67P+Mhps7OD5 8SF13AzLvHNqsM1CWF1er7LfFugfIj31id7tYoiaZ6UP18ceK3fXbseSrFt9tF/4e63JP jF8pciuRtiDg6rzrIYa7Hpts1zYRsSA65sYsPvVZa1v281yllalwKQLVXgHLaJSLpogWq 9v/TWM2Vbttw/2M74Nwtg14oXb82iWnhAwhj9KKiZ63UFPAb9aJuMb10VqfU/eJo5jst/ OG7ayMIE6s906JltWwgmDQSPLpDuEwwH8czjSuOHX/MyOamDpN5dMbZnIcSgy2a0ydQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="CCxA/qxX"; 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 0954D606A89E for ; Wed, 11 Nov 2026 15:24:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=CCxA/qxX Received: by smtp.kernel.org (Postfix) with ESMTPSA id D591C1F00A14; Wed, 11 Nov 2026 15:24:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794410682; bh=YiGFuS54+M9xVjICHulOyYObpz+KXxAGRy2R5hyjO90=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CCxA/qxXSlr/x3Udw2uAB6nesNVERJJhUHP69KGMHcQJA5qqadcWYMHXgRADlDZTe R95lOar6vRIY5BUvbFyHzX3MOWQfPeyDZRBnXYUaMCwH4jSW7A/potOMIsoW0rkdk7 7V74BocHgPYSyxQct72TS5zHP52CSYBLA7AUhQxWly+I8n5atgcMKAN9aqdmJpHbhP 7W2eQoJSzToWer0MrbLUUyf4u67DgOBg7hEy7dhYiX3UGAGYgVl8EzdlgPtXOpuNy/ 7js6O9PCWCKV4j2xos886TWndvA3OH6Wz25xEB9KiL7PaWY33ImvnuX8duu6aG+C/9 jCd+NxoYfiFyA== From: Sasha Levin To: stable@vger.kernel.org Cc: Bradley Morgan , Andrew Morton , Petr Mladek , Guenetr Roeck , Sashiko , Wang Jinchao , Wim Van Sebroeck , Sasha Levin Subject: [PATCH 6.18.y 2/2] panic: restore variable arguments to nmi_panic() Date: Wed, 11 Nov 2026 10:24:39 -0500 Message-ID: <20261111152433.2592922-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261111152433.2592922-1-sashal@kernel.org> References: <20261107051109-failed-6.18-ed9e4c1ff15d@kernel.org> <20261111152433.2592922-1-sashal@kernel.org> 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 From: Bradley Morgan [ Upstream commit ed9e4c1ff15d5b935f467811541ca0aa6e49c5d0 ] nmi_panic() used to accept variable arguments until commit ebc41f20d77f ("panic: change nmi_panic from macro to function") flattened it to a final message string. vpanic() did not exist back then, so the function had to format through panic("%s", msg). Bring the variable arguments back and format with vpanic() directly. The next patch makes nmi_panic() try the panic_force_cpu= redirect before claiming panic_cpu. panic_try_force_cpu() needs to print the message but it is used also by panic() which accepts variable argument list. The string could be formatted only when a CPU gets assigned to process the redirection. Otherwise, there might be a race when writing to the `panic_force_buf`. No current caller passes a string with format specifiers. The closest one is hpwdt_pretimeout(), which builds panic_msg with hex_byte_pack() and has only two variants, both plain strings. But the new __printf() annotation on nmi_panic() would warn with -Wformat-security there because the buffer is passed directly as the format argument, so switch it to nmi_panic(regs, "%s", panic_msg). [pmladek@suse.com: changelog fix] Link: https://lore.kernel.org/arJxFybmtD7OBIcL@pathway.suse.cz Link: https://lore.kernel.org/20260916182957.7788-5-brads@mainlining.org Signed-off-by: Bradley Morgan Signed-off-by: Andrew Morton Suggested-by: Petr Mladek Reviewed-by: Petr Mladek Cc: Guenetr Roeck Cc: Sashiko Cc: Wang Jinchao Cc: Wim Van Sebroeck Cc: Signed-off-by: Sasha Levin --- drivers/watchdog/hpwdt.c | 2 +- include/linux/panic.h | 3 ++- kernel/panic.c | 10 ++++++++-- 3 files changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c index ba08189937ec6..32e9ac24e0d5f 100644 --- a/drivers/watchdog/hpwdt.c +++ b/drivers/watchdog/hpwdt.c @@ -198,7 +198,7 @@ static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs) } hex_byte_pack(panic_msg, nmistat); - nmi_panic(regs, panic_msg); + nmi_panic(regs, "%s", panic_msg); return NMI_HANDLED; } diff --git a/include/linux/panic.h b/include/linux/panic.h index 6f972a66c13ee..2ccea58bea810 100644 --- a/include/linux/panic.h +++ b/include/linux/panic.h @@ -13,7 +13,8 @@ __printf(1, 2) void panic(const char *fmt, ...) __noreturn __cold; __printf(1, 0) void vpanic(const char *fmt, va_list args) __noreturn __cold; -void nmi_panic(struct pt_regs *regs, const char *msg); +__printf(2, 3) +void nmi_panic(struct pt_regs *regs, const char *fmt, ...); void check_panic_on_warn(const char *origin); extern void oops_enter(void); extern void oops_exit(void); diff --git a/kernel/panic.c b/kernel/panic.c index 7f8725f2154b8..e1d0c16fc5266 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -360,13 +360,19 @@ EXPORT_SYMBOL(panic_on_other_cpu); * nmi_panic_self_stop() which can provide architecture dependent code such * as saving register state for crash dump. */ -void nmi_panic(struct pt_regs *regs, const char *msg) +void nmi_panic(struct pt_regs *regs, const char *fmt, ...) { + va_list args; + + va_start(args, fmt); + if (panic_try_start()) - panic("%s", msg); + vpanic(fmt, args); if (panic_on_other_cpu()) nmi_panic_self_stop(regs); + + va_end(args); } EXPORT_SYMBOL(nmi_panic); -- 2.53.0