Re: [PATCH]: Fix bogus softlockup warning with sysrq-t

From: Prarit Bhargava
Date: Tue Mar 27 2007 - 13:35:42 EST




Jeremy Fitzhardinge wrote:

diff -r 4c81d8cafb67 drivers/char/sysrq.c
--- a/drivers/char/sysrq.c Tue Mar 27 01:16:07 2007 -0700
+++ b/drivers/char/sysrq.c Tue Mar 27 01:18:05 2007 -0700
@@ -408,6 +408,8 @@ void __handle_sysrq(int key, struct tty_
int i;
unsigned long flags;
+ softlockup_global_disable();
+
spin_lock_irqsave(&sysrq_key_table_lock, flags);
orig_log_level = console_loglevel;
console_loglevel = 7;
@@ -445,6 +447,8 @@ void __handle_sysrq(int key, struct tty_
console_loglevel = orig_log_level;
}
spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
+
+ softlockup_global_enable();
}

I wonder if that's too strong of a fix. It's only the sysrq-t case that is the problem. AFAIK, none of the other sysrq-t operations hold the tasklist_lock for a long time. I'd move these around show_state.

P.
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