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From: Arnd Bergmann <arnd@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>,
	Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Tom Rix <trix@redhat.com>,
	"Liam R. Howlett" <Liam.Howlett@oracle.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Suren Baghdasaryan <surenb@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev
Subject: [PATCH 1/3] mm/mmap/vma_merge: actually set next to NULL if not applicable
Date: Thu, 23 Mar 2023 12:58:34 +0100	[thread overview]
Message-ID: <20230323115903.1483668-1-arnd@kernel.org> (raw)

From: Arnd Bergmann <arnd@arndb.de>

As clang builds point out, the variable 'next' is now uninitialized
in some conditions as a result of a previous patch that tried to
rely on it being NULL here:

mm/mmap.c:939:11: error: variable 'next' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
        else if (!curr)
                 ^~~~~
mm/mmap.c:952:15: note: uninitialized use occurs here
        merge_next = next && mpol_equal(policy, vma_policy(next)) &&
                     ^~~~

Fixes: e887ecae997e ("mm/mmap/vma_merge: set next to NULL if not applicable")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 mm/mmap.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/mmap.c b/mm/mmap.c
index 54099a604cf8..c01d43bd694e 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -939,6 +939,8 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm,
 	else if (!curr)
 		/* Is there a VMA next to a hole (case 1 - 3) or prev (4)? */
 		next = vma_lookup(mm, end);
+	else
+		next = NULL;
 
 	/* Can we merge the predecessor? */
 	if (prev && addr == prev->vm_end && mpol_equal(vma_policy(prev), policy)
-- 
2.39.2



             reply	other threads:[~2023-03-23 11:59 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-23 11:58 Arnd Bergmann [this message]
2023-03-23 11:58 ` [PATCH 2/3] mm: vmalloc: fix vmap_ram_vread_iter() return value Arnd Bergmann
2023-03-23 12:05   ` Lorenzo Stoakes
2023-03-23 11:58 ` [PATCH 3/3] mm: vmalloc: mark zero_iter() static Arnd Bergmann
2023-03-23 12:06   ` Lorenzo Stoakes
2023-03-23 12:03 ` [PATCH 1/3] mm/mmap/vma_merge: actually set next to NULL if not applicable Lorenzo Stoakes

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