linux-kernel - Re: [PATCH] mm: thp: fix a double unlock bug

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Date:   Tue, 1 Jun 2021 11:08:49 +0100
From:   Mel Gorman <mgorman@...e.de>
To:     Dan Carpenter <dan.carpenter@...cle.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Yang Shi <shy828301@...il.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] mm: thp: fix a double unlock bug

On Tue, Jun 01, 2021 at 12:24:09PM +0300, Dan Carpenter wrote:
> We're supposed to be holding the "vmf->ptl" spin_lock when we goto
> out_map.  The lock is dropped after if finishes cleaning up.
> 
> Fixes: 9aff7b33c74a ("mm: thp: refactor NUMA fault handling")
> Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>

Ouch.

Acked-by: Mel Gorman <mgorman@...e.de>

However, that git commit is not stable. Instead of Fixes: I would
suggest renaming the patch to "mm: thp: refactor NUMA fault handling
-fix" and replacing Fixes with "This patch is a fix to the mmotm patch
mm-thp-refactor-numa-fault-handling.patch". Andrew usually slots that
into the correct place in his quilt series and collapses the fixes before
sending to Linus which works better with bisection.

-- 
Mel Gorman
SUSE Labs