linux-kernel - [PATCH printk v3 01/19] printk: nbcon: Clarify nbcon_get_default

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240722171939.3349410-2-john.ogness@linutronix.de>
Date: Mon, 22 Jul 2024 19:25:21 +0206
From: John Ogness <john.ogness@...utronix.de>
To: Petr Mladek <pmladek@...e.com>
Cc: Sergey Senozhatsky <senozhatsky@...omium.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org
Subject: [PATCH printk v3 01/19] printk: nbcon: Clarify nbcon_get_default_prio() context

Correct the kerneldoc and code comments that claimed migration must
be disabled for nbcon_get_default_prio(). This is not true.

Add the explation in the kerneldoc.

Signed-off-by: John Ogness <john.ogness@...utronix.de>
---
 kernel/printk/nbcon.c  | 5 ++++-
 kernel/printk/printk.c | 2 --
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/printk/nbcon.c b/kernel/printk/nbcon.c
index ef6e76db0f5a..d8388faa6500 100644
--- a/kernel/printk/nbcon.c
+++ b/kernel/printk/nbcon.c
@@ -970,9 +970,12 @@ static __ref unsigned int *nbcon_get_cpu_emergency_nesting(void)
  * nbcon_get_default_prio - The appropriate nbcon priority to use for nbcon
  *				printing on the current CPU
  *
- * Context:	Any context which could not be migrated to another CPU.
+ * Context:	Any context.
  * Return:	The nbcon_prio to use for acquiring an nbcon console in this
  *		context for printing.
+ *
+ * Allowing migration enabled relies on the fact that a context cannot be
+ * migrated to panic or emergency state CPUs.
  */
 enum nbcon_prio nbcon_get_default_prio(void)
 {
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index d0bff0b0abfd..5090c0591f88 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2401,8 +2401,6 @@ asmlinkage int vprintk_emit(int facility, int level,
 		 * printing of all remaining records to all consoles so that
 		 * this context can return as soon as possible. Hopefully
 		 * another printk() caller will take over the printing.
-		 *
-		 * Also, nbcon_get_default_prio() requires migration disabled.
 		 */
 		preempt_disable();
 
-- 
2.39.2