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From: Roberto Bergantinos Corpas <rbergant@redhat.com>
To: sfrench@samba.org
Cc: linux-cifs@vger.kernel.org
Subject: [PATCH] CIFS: cifs_read_allocate_pages: don't iterate through whole page array on ENOMEM
Date: Tue, 28 May 2019 09:38:14 +0200	[thread overview]
Message-ID: <20190528073814.984-1-rbergant@redhat.com> (raw)

 In cifs_read_allocate_pages, in case of ENOMEM, we go through
whole rdata->pages array but we have failed the allocation before
nr_pages, therefore we may end up calling put_page with NULL
pointer, causing oops

Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com>
---
 fs/cifs/file.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index ce9a5be11df5..06e27ac6d82c 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3216,7 +3216,9 @@ cifs_read_allocate_pages(struct cifs_readdata *rdata, unsigned int nr_pages)
 	}
 
 	if (rc) {
-		for (i = 0; i < nr_pages; i++) {
+		unsigned int nr_page_failed = i;
+
+		for (i = 0; i < nr_page_failed; i++) {
 			put_page(rdata->pages[i]);
 			rdata->pages[i] = NULL;
 		}
-- 
2.14.5


                 reply	other threads:[~2019-05-28  7:38 UTC|newest]

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