The patch titled
Subject: mm/mempolicy: fix exception handling in shared_policy_replace()
has been added to the -mm mm-unstable branch. Its filename is
mm-mempolicy-fix-exception-handling-in-shared_policy_replace.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mempolicy-fix-exception-handling-in-shared_policy_replace.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Markus Elfring <Markus.Elfring@xxxxxx>
Subject: mm/mempolicy: fix exception handling in shared_policy_replace()
Date: Thu, 23 Mar 2023 18:30:48 +0100
The label â??err_outâ?? was used to jump to another pointer check despite of
the detail in the implementation of the function â??shared_policy_replaceâ??
that it was determined already that a corresponding variable contained a
null pointer because of a failed call of the function â??kmem_cache_allocâ??.
1. Use more appropriate labels instead.
2. The implementation of the function â??mpol_putâ?? contains a pointer check
  for its single input parameter.
  Thus delete a redundant check in the caller.
This issue was detected by using the Coccinelle software.
Fixes: 42288fe366c4f1ce7522bc9f27d0bc2a81c55264 ("mm: mempolicy: Convert shared_policy mutex to spinlock")
Signed-off-by: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mempolicy.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
--- a/mm/mempolicy.c~mm-mempolicy-fix-exception-handling-in-shared_policy_replace
+++ a/mm/mempolicy.c
@@ -2736,13 +2736,12 @@ restart:
sp_insert(sp, new);
write_unlock(&sp->lock);
ret = 0;
+put_mpol:
+ mpol_put(mpol_new);
-err_out:
- if (mpol_new)
- mpol_put(mpol_new);
if (n_new)
kmem_cache_free(sn_cache, n_new);
-
+exit:
return ret;
alloc_new:
@@ -2750,10 +2749,10 @@ alloc_new:
ret = -ENOMEM;
n_new = kmem_cache_alloc(sn_cache, GFP_KERNEL);
if (!n_new)
- goto err_out;
+ goto exit;
mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL);
if (!mpol_new)
- goto err_out;
+ goto put_mpol;
atomic_set(&mpol_new->refcnt, 1);
goto restart;
}
_
Patches currently in -mm which might be from Markus.Elfring@xxxxxx are
mm-mempolicy-fix-exception-handling-in-shared_policy_replace.patch
