queue-6.8/printk-for-suppress_panic_printk-check-for-other-cpu.patch

   1 From 71ae9b330f906cb7e8c43e1fd0c7136e54bc0034 Mon Sep 17 00:00:00 2001
   2 From: Sasha Levin <sashal@kernel.org>
   3 Date: Wed, 7 Feb 2024 14:46:55 +0106
   4 Subject: printk: For @suppress_panic_printk check for other CPU in panic
   5
   6 From: John Ogness <john.ogness@linutronix.de>
   7
   8 [ Upstream commit 0ab7cdd00491b532591ef065be706301de7e448f ]
   9
  10 Currently @suppress_panic_printk is checked along with
  11 non-matching @panic_cpu and current CPU. This works
  12 because @suppress_panic_printk is only set when
  13 panic_in_progress() is true.
  14
  15 Rather than relying on the @suppress_panic_printk semantics,
  16 use the concise helper function other_cpu_in_progress(). The
  17 helper function exists to avoid open coding such tests.
  18
  19 Signed-off-by: John Ogness <john.ogness@linutronix.de>
  20 Reviewed-by: Petr Mladek <pmladek@suse.com>
  21 Link: https://lore.kernel.org/r/20240207134103.1357162-7-john.ogness@linutronix.de
  22 Signed-off-by: Petr Mladek <pmladek@suse.com>
  23 Signed-off-by: Sasha Levin <sashal@kernel.org>
  24 ---
  25  kernel/printk/printk.c | 3 +--
  26  1 file changed, 1 insertion(+), 2 deletions(-)
  27
  28 diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
  29 index 7a835b277e98d..e1b992652ab25 100644
  30 --- a/kernel/printk/printk.c
  31 +++ b/kernel/printk/printk.c
  32 @@ -2328,8 +2328,7 @@ asmlinkage int vprintk_emit(int facility, int level,
  33         if (unlikely(suppress_printk))
  34                 return 0;
  35
  36 -       if (unlikely(suppress_panic_printk) &&
  37 -           atomic_read(&panic_cpu) != raw_smp_processor_id())
  38 +       if (unlikely(suppress_panic_printk) && other_cpu_in_panic())
  39                 return 0;
  40
  41         if (level == LOGLEVEL_SCHED) {
  42 --
  43 2.43.0
  44