From nobody Sun Dec 28 00:48:05 2025 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 D9F646E2C1 for ; Thu, 14 Dec 2023 21:42:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Fl9EDpri"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="F1l2H1G/" From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1702590126; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EjNlI5JonKv0m/kINdXCywSbWYOfTvFxrSFxNOQW5Ko=; b=Fl9EDpriC4isCU/BtgR2fdrIobGrK+hq+Ifz9dlN3/a1ySYUNd1l8M8/WQCtjZso2uBmwY Uz7xWkah907tDY34I+G0Rv68veVCA64rwBs8UMzMFc+M92sG8xPSNeA0g6op0LWfTGnChz ITiH2Li9Zl2EVtitjdzhIS4aK60cshGIyCblZ1/0DdbZdVctvHoWpulv1yRRX2inGcKUBK DuyUZH6NSSFdU35rNVJz8t+vO+yF+rDyB7faIZxTKCYvBPVQTzwqbL6NX9AG3GTBfteHGz idEOWRMKsuB2x0026kUWgjX8jIZ91v8kZ5MXyoYvpq96CtrXV5MahJvvRB6Hug== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1702590126; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=EjNlI5JonKv0m/kINdXCywSbWYOfTvFxrSFxNOQW5Ko=; b=F1l2H1G/fVUwDSZT60vtw3F6/tqAwdlqkl2Nn/lHaRx4HraBC0vfmiFsvJOZUmAE6vQqJM g6/09CwYWZ8gPIDg== To: Petr Mladek Cc: Sergey Senozhatsky , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: [PATCH printk v3 07/14] printk: Add this_cpu_in_panic() Date: Thu, 14 Dec 2023 22:47:54 +0106 Message-Id: <20231214214201.499426-8-john.ogness@linutronix.de> In-Reply-To: <20231214214201.499426-1-john.ogness@linutronix.de> References: <20231214214201.499426-1-john.ogness@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" There is already panic_in_progress() and other_cpu_in_panic(), but checking if the current CPU is the panic CPU must still be open coded. Add this_cpu_in_panic() to complete the set. Signed-off-by: John Ogness Reviewed-by: Petr Mladek --- kernel/printk/internal.h | 1 + kernel/printk/printk.c | 43 +++++++++++++++++++++------------------- 2 files changed, 24 insertions(+), 20 deletions(-) diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index 6c2afee5ef62..ac2d9750e5f8 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -130,6 +130,7 @@ struct printk_message { }; =20 bool other_cpu_in_panic(void); +bool this_cpu_in_panic(void); bool printk_get_next_message(struct printk_message *pmsg, u64 seq, bool is_extended, bool may_supress); =20 diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 22bb45d8f2f2..82dc2c7949b7 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -347,6 +347,29 @@ static bool panic_in_progress(void) return unlikely(atomic_read(&panic_cpu) !=3D PANIC_CPU_INVALID); } =20 +/* Return true if a panic is in progress on the current CPU. */ +bool this_cpu_in_panic(void) +{ + /* + * We can use raw_smp_processor_id() here because it is impossible for + * the task to be migrated to the panic_cpu, or away from it. If + * panic_cpu has already been set, and we're not currently executing on + * that CPU, then we never will be. + */ + return unlikely(atomic_read(&panic_cpu) =3D=3D raw_smp_processor_id()); +} + +/* + * Return true if a panic is in progress on a remote CPU. + * + * On true, the local CPU should immediately release any printing resources + * that may be needed by the panic CPU. + */ +bool other_cpu_in_panic(void) +{ + return (panic_in_progress() && !this_cpu_in_panic()); +} + /* * This is used for debugging the mess that is the VT code by * keeping track if we have the console semaphore held. It's @@ -2592,26 +2615,6 @@ static int console_cpu_notify(unsigned int cpu) return 0; } =20 -/* - * Return true if a panic is in progress on a remote CPU. - * - * On true, the local CPU should immediately release any printing resources - * that may be needed by the panic CPU. - */ -bool other_cpu_in_panic(void) -{ - if (!panic_in_progress()) - return false; - - /* - * We can use raw_smp_processor_id() here because it is impossible for - * the task to be migrated to the panic_cpu, or away from it. If - * panic_cpu has already been set, and we're not currently executing on - * that CPU, then we never will be. - */ - return atomic_read(&panic_cpu) !=3D raw_smp_processor_id(); -} - /** * console_lock - block the console subsystem from printing * --=20 2.39.2