+ mm-shmem-dont-truncate-page-if-memory-failure-happens-fix.patch added to -mm tree

* + mm-shmem-dont-truncate-page-if-memory-failure-happens-fix.patch added to -mm tree
@ 2021-10-22  2:35 akpm
  2021-10-22  6:42 ` Stephen Rothwell
  0 siblings, 1 reply; 2+ messages in thread
From: akpm @ 2021-10-22  2:35 UTC (permalink / raw)
  To: bot, mm-commits, nathan, sfr, shy828301


The patch titled
     Subject: mm/memory_failure: initialize extra_pins in me_pagecache_clean()
has been added to the -mm tree.  Its filename is
     mm-shmem-dont-truncate-page-if-memory-failure-happens-fix.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-shmem-dont-truncate-page-if-memory-failure-happens-fix.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-shmem-dont-truncate-page-if-memory-failure-happens-fix.patch

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------------------------------------------------------
From: Nathan Chancellor <nathan@kernel.org>
Subject: mm/memory_failure: initialize extra_pins in me_pagecache_clean()

Clang warns:

mm/memory-failure.c:892:6: error: variable 'extra_pins' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
        if (!mapping) {
            ^~~~~~~~
mm/memory-failure.c:915:32: note: uninitialized use occurs here
        if (has_extra_refcount(ps, p, extra_pins))
                                      ^~~~~~~~~~
mm/memory-failure.c:892:2: note: remove the 'if' if its condition is always false
        if (!mapping) {
        ^~~~~~~~~~~~~~~
mm/memory-failure.c:879:6: error: variable 'extra_pins' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
        if (PageAnon(p)) {
            ^~~~~~~~~~~
mm/memory-failure.c:915:32: note: uninitialized use occurs here
        if (has_extra_refcount(ps, p, extra_pins))
                                      ^~~~~~~~~~
mm/memory-failure.c:879:2: note: remove the 'if' if its condition is always false
        if (PageAnon(p)) {
        ^~~~~~~~~~~~~~~~~~
mm/memory-failure.c:871:17: note: initialize the variable 'extra_pins' to silence this warning
        bool extra_pins;
                       ^
                        = 0
2 errors generated.

Initialize extra_pins to false so that it is not used uninitialized.

Link: https://lkml.kernel.org/r/20211021180336.2328086-1-nathan@kernel.org
Fixes: d882a43a0011 ("mm: shmem: don't truncate page if memory failure happens")
Link: https://github.com/ClangBuiltLinux/linux/issues/1487
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Acked-by: Yang Shi <shy828301@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory-failure.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/memory-failure.c~mm-shmem-dont-truncate-page-if-memory-failure-happens-fix
+++ a/mm/memory-failure.c
@@ -868,7 +868,7 @@ static int me_pagecache_clean(struct pag
 {
 	int ret;
 	struct address_space *mapping;
-	bool extra_pins;
+	bool extra_pins = false;
 
 	delete_from_lru_cache(p);
 
_

Patches currently in -mm which might be from nathan@kernel.org are

mm-shmem-dont-truncate-page-if-memory-failure-happens-fix.patch


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