The patch titled
eCryptfs: use page_alloc not kmalloc to get a page of memory
has been added to the -mm tree. Its filename is
ecryptfs-use-page_alloc-not-kmalloc-to-get-a-page-of-memory.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: eCryptfs: use page_alloc not kmalloc to get a page of memory
From: Eric Sandeen <sandeen@xxxxxxxxxx>
With SLUB debugging turned on in 2.6.26, I was getting memory corruption
when testing eCryptfs. The root cause turned out to be that eCryptfs was
doing kmalloc(PAGE_CACHE_SIZE); virt_to_page() and treating that as a nice
page-aligned chunk of memory. But at least with SLUB debugging on, this
is not always true, and the page we get from virt_to_page does not
necessarily match the PAGE_CACHE_SIZE worth of memory we got from kmalloc.
My simple testcase was 2 loops doing "rm -f fileX; cp /tmp/fileX ." for 2
different multi-megabyte files. With this change I no longer see the
corruption.
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Acked-by: Michael Halcrow <mhalcrow@xxxxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx> [2.6.25.x, 2.6.26.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ecryptfs/crypto.c | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)
diff -puN fs/ecryptfs/crypto.c~ecryptfs-use-page_alloc-not-kmalloc-to-get-a-page-of-memory fs/ecryptfs/crypto.c
--- a/fs/ecryptfs/crypto.c~ecryptfs-use-page_alloc-not-kmalloc-to-get-a-page-of-memory
+++ a/fs/ecryptfs/crypto.c
@@ -475,8 +475,8 @@ int ecryptfs_encrypt_page(struct page *p
{
struct inode *ecryptfs_inode;
struct ecryptfs_crypt_stat *crypt_stat;
- char *enc_extent_virt = NULL;
- struct page *enc_extent_page;
+ char *enc_extent_virt;
+ struct page *enc_extent_page = NULL;
loff_t extent_offset;
int rc = 0;
@@ -492,14 +492,14 @@ int ecryptfs_encrypt_page(struct page *p
page->index);
goto out;
}
- enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
- if (!enc_extent_virt) {
+ enc_extent_page = alloc_page(GFP_USER);
+ if (!enc_extent_page) {
rc = -ENOMEM;
ecryptfs_printk(KERN_ERR, "Error allocating memory for "
"encrypted extent\n");
goto out;
}
- enc_extent_page = virt_to_page(enc_extent_virt);
+ enc_extent_virt = kmap(enc_extent_page);
for (extent_offset = 0;
extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
extent_offset++) {
@@ -527,7 +527,10 @@ int ecryptfs_encrypt_page(struct page *p
}
}
out:
- kfree(enc_extent_virt);
+ if (enc_extent_page) {
+ kunmap(enc_extent_page);
+ __free_page(enc_extent_page);
+ }
return rc;
}
@@ -609,8 +612,8 @@ int ecryptfs_decrypt_page(struct page *p
{
struct inode *ecryptfs_inode;
struct ecryptfs_crypt_stat *crypt_stat;
- char *enc_extent_virt = NULL;
- struct page *enc_extent_page;
+ char *enc_extent_virt;
+ struct page *enc_extent_page = NULL;
unsigned long extent_offset;
int rc = 0;
@@ -627,14 +630,14 @@ int ecryptfs_decrypt_page(struct page *p
page->index);
goto out;
}
- enc_extent_virt = kmalloc(PAGE_CACHE_SIZE, GFP_USER);
- if (!enc_extent_virt) {
+ enc_extent_page = alloc_page(GFP_USER);
+ if (!enc_extent_page) {
rc = -ENOMEM;
ecryptfs_printk(KERN_ERR, "Error allocating memory for "
"encrypted extent\n");
goto out;
}
- enc_extent_page = virt_to_page(enc_extent_virt);
+ enc_extent_virt = kmap(enc_extent_page);
for (extent_offset = 0;
extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
extent_offset++) {
@@ -662,7 +665,10 @@ int ecryptfs_decrypt_page(struct page *p
}
}
out:
- kfree(enc_extent_virt);
+ if (enc_extent_page) {
+ kunmap(enc_extent_page);
+ __free_page(enc_extent_page);
+ }
return rc;
}
_
Patches currently in -mm which might be from sandeen@xxxxxxxxxx are
origin.patch
ecryptfs-use-page_alloc-not-kmalloc-to-get-a-page-of-memory.patch
linux-next.patch
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