linux-kernel - Re: [PATCH 2/6] ipc/sem.c: Bugfix for semctl(,,GETZCNT)

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Date:	Mon, 12 May 2014 11:11:40 -0700
From:	Davidlohr Bueso <davidlohr@...com>
To:	Manfred Spraul <manfred@...orfullife.com>
Cc:	Davidlohr Bueso <davidlohr.bueso@...com>,
	Michael Kerrisk <mtk.manpages@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>, 1vier1@....de
Subject: Re: [PATCH 2/6] ipc/sem.c: Bugfix for semctl(,,GETZCNT)

On Sat, 2014-05-10 at 12:03 +0200, Manfred Spraul wrote:
> GETZCNT is supposed to return the number of threads that wait until
> a semaphore value becomes 0.
> The current implementation overlooks complex operations that contain
> both wait-for-zero operation and operations that alter at least one semaphore.

Indeed. the pending_alter list does represent blocked processes on the
sem. Good catch. Btw, how on earth did you run into this? reading the
code or a real case?

> 
> The patch fixes that.
> It's intentionally copy&paste, this will be cleaned up in the next patch.

Instead I would have expected this patch to actually come after the
count_* refactoring.


> Signed-off-by: Manfred Spraul <manfred@...orfullife.com>

Reviewed-by: Davidlohr Bueso <davidlohr@...com>

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