From: Colin King <colin.king@canonical.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Minchan Kim <minchan@kernel.org>,
John Hubbard <jhubbard@nvidia.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-mm@kvack.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] mm: cma: Fix potential null dereference on pointer cma
Date: Tue, 16 Mar 2021 10:04:33 +0000 [thread overview]
Message-ID: <20210316100433.17665-1-colin.king@canonical.com> (raw)
From: Colin Ian King <colin.king@canonical.com>
At the start of the function there is a null pointer check on cma
and then branch to error handling label 'out'. The subsequent call
to cma_sysfs_fail_pages_count dereferences cma, hence there is a
potential null pointer deference issue. Fix this by only calling
cma_sysfs_fail_pages_count if cma is not null.
Addresses-Coverity: ("Dereference after null check")
Fixes: dc4764f7e9ac ("mm: cma: support sysfs")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
mm/cma.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/cma.c b/mm/cma.c
index 6d4dbafdb318..90e27458ddb7 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -512,7 +512,8 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
cma_sysfs_alloc_pages_count(cma, count);
} else {
count_vm_event(CMA_ALLOC_FAIL);
- cma_sysfs_fail_pages_count(cma, count);
+ if (cma)
+ cma_sysfs_fail_pages_count(cma, count);
}
return page;
--
2.30.2
next reply other threads:[~2021-03-16 10:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 10:04 Colin King [this message]
2021-03-16 18:09 ` [PATCH] mm: cma: Fix potential null dereference on pointer cma Minchan Kim
2021-03-17 7:13 ` John Hubbard
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