From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.mainlining.org (mail.mainlining.org [5.75.144.95]) (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 415424C2243; Wed, 16 Sep 2026 18:30:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=5.75.144.95 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789583420; cv=none; b=X2gNEsiJP7U2HucVrdO9ug9oxpL5E6xBWtW5683zuU4sAIHHJXnvQB+WC0SfWu73Gj5uO9EqUrj1mBMaoPAcvxFWLzMwIM0BpXqlNqzF8fBTQ0rZX2KzLY24UtKZ553H2igncqp6NBprgYsfiUEZWUk8KQCLZn5EALEmkLNC47Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789583420; c=relaxed/simple; bh=dyv4fdkjAz/+IS25pIkAfJLfB8i1e/864CKJn6kTrSo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NDX0c6z7ZwQP2fPN8DURq9KIHfhnrUazpruqDWnZdG4cZfZpZcd1bxIQskfX7UdY83JruihRpSPzWJfBy9S8vgOpaXHQYKAo8S1DBTj4onLxqqh/hEqNNLObw0fIrWRDtKbvfvS2TJFeareOdFDjXq38Ea3h+1X9KP5vS7FvCUA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mainlining.org; spf=pass smtp.helo=mail.mainlining.org; arc=none smtp.client-ip=5.75.144.95 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mainlining.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.helo=mail.mainlining.org From: Bradley Morgan To: Andrew Morton Cc: Petr Mladek , Jinchao Wang , Craig Lamparter , Wim Van Sebroeck , Guenter Roeck , linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org, Bradley Morgan Subject: [PATCH v7 4/6] panic: restore variable arguments to nmi_panic() Date: Wed, 16 Sep 2026 18:29:55 +0000 Message-ID: <20260916182957.7788-5-brads@mainlining.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260916182957.7788-1-brads@mainlining.org> References: <20260916182957.7788-1-brads@mainlining.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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, which needs the arguments twice: once to format the message for the redirected CPU and once for vpanic() when no redirect happens. Passing a final string would lose that. 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). Suggested-by: Petr Mladek Signed-off-by: Bradley Morgan --- 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 8af1fad2de0b..78227d200afe 100644 --- a/drivers/watchdog/hpwdt.c +++ b/drivers/watchdog/hpwdt.c @@ -199,7 +199,7 @@ 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 98dd7dfd27de..17e61b61c45f 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 7388eb81a1c4..e240ca06faab 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -518,13 +518,19 @@ 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); -- 2.47.3