[PATCH AUTOSEL 5.15 29/50] printk: Add panic_in_progress helper

Sasha Levin
2022-03-30T12:10:19Z

From: Stephen Brennan <stephen.s.brennan@oracle.com>

[ Upstream commit 77498617857f68496b360081dde1a492d40c28b2 ]

This will be used help avoid deadlocks during panics. Although it would
be better to include this in linux/panic.h, it would require that header
to include linux/atomic.h as well. On some architectures, this results
in a circular dependency as well. So instead add the helper directly to
printk.c.

Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220202171821.179394-2-stephen.s.brennan@oracle.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/printk/printk.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 99221b016c68..f9aebe88cc53 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -256,6 +256,11 @@ static void __up_console_sem(unsigned long ip)
}
#define up_console_sem() __up_console_sem(_RET_IP_)

+static bool panic_in_progress(void)
+{
+ return unlikely(atomic_read(&panic_cpu) != PANIC_CPU_INVALID);
+}
+
/*
* This is used for debugging the mess that is the VT code by
* keeping track if we have the console semaphore held. It's
--
2.34.1