lkml.org 
[lkml]   [2006]   [Dec]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Conditionally check expected_preempt_count in __resched_legal()

* Mark Fasheh <mark.fasheh@oracle.com> wrote:

> Commit 2d7d253548cffdce80f4e03664686e9ccb1b0ed7 ("fix cond_resched() fix")
> introduced an 'expected_preempt_count' parameter to __resched_legal() to fix
> a bug where it was returning a false negative when called from
> cond_resched_lock() and preemption was enabled.
>
> Unfortunately this broke things for when preemption is disabled.
> preempt_count() will always return zero, thus failing the check against
> any value of expected_preempt_count not equal to zero. cond_resched_lock()
> for example, passes an expected_preempt_count value of 1.
>
> So fix the fix for the cond_resched() fix by skipping the check of
> preempt_count() against expected_preempt_count when preemption is disabled.
>
> Credit should go to Sunil Mushran for spotting the bug during testing.
>
> Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

well spotted. I'm wondering whether this piece of code has the highest
amount of fixes per line of code ratio in the whole kernel ...

Acked-by: Ingo Molnar <mingo@elte.hu>

Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-12-13 21:09    [W:0.216 / U:0.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site