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Subject[PATCH] printk: defer_console_output: do not assume interrupts disabled
Date
With commit 458df9fd4815 ("printk: remove separate printk_sched
buffers and use printk buf instead") defer_console_output() was
changed to no longer disable interrupts. However, it used the
function __this_cpu_or(), which assumes interrupts disabled. That
also should have been changed to this_cpu_or().

Although defer_console_output() is mostly used when interrupts are
disabled, this is not always the case. One example is
get_random_bytes(), which is often called with interrupts enabled.

get_random_bytes()
warn_unseeded_randomness()
printk_deferred()

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
---
kernel/printk/printk.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 82abfaf3c2aa..164ccdb9423e 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -3262,7 +3262,7 @@ void defer_console_output(void)
return;

preempt_disable();
- __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
+ this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
preempt_enable();
}
base-commit: 88808fbbead481aedb46640a5ace69c58287f56a
--
2.30.2

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