diff options
| author | Andrew Morton <akpm@osdl.org> | 2006-10-11 01:21:46 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-10-11 11:14:21 -0700 |
| commit | e5657933863f43cc6bb76a54d659303dafaa9e58 (patch) | |
| tree | 7f6351194953b0d167ea79749d9fcaf9ae7f6a1f /fs | |
| parent | e0ab2928cc2202f13f0574d4c6f567f166d307eb (diff) | |
[PATCH] grow_buffers() infinite loop fix
If grow_buffers() is for some reason passed a block number which wants to lie
outside the maximum-addressable pagecache range (PAGE_SIZE * 4G bytes) then it
will accidentally truncate `index' and will then instnatiate a page at the
wrong pagecache offset. This causes __getblk_slow() to go into an infinite
loop.
This can happen with corrupted disks, or with software errors elsewhere.
Detect that, and handle it.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/buffer.c | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index eeb8ac1aa85..2a7828c0e59 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1042,8 +1042,21 @@ grow_buffers(struct block_device *bdev, sector_t block, int size) } while ((size << sizebits) < PAGE_SIZE); index = block >> sizebits; - block = index << sizebits; + /* + * Check for a block which wants to lie outside our maximum possible + * pagecache index. (this comparison is done using sector_t types). + */ + if (unlikely(index != block >> sizebits)) { + char b[BDEVNAME_SIZE]; + + printk(KERN_ERR "%s: requested out-of-range block %llu for " + "device %s\n", + __FUNCTION__, (unsigned long long)block, + bdevname(bdev, b)); + return -EIO; + } + block = index << sizebits; /* Create a page with the proper size buffers.. */ page = grow_dev_page(bdev, block, index, size); if (!page) @@ -1070,12 +1083,16 @@ __getblk_slow(struct block_device *bdev, sector_t block, int size) for (;;) { struct buffer_head * bh; + int ret; bh = __find_get_block(bdev, block, size); if (bh) return bh; - if (!grow_buffers(bdev, block, size)) + ret = grow_buffers(bdev, block, size); + if (ret < 0) + return NULL; + if (ret == 0) free_more_memory(); } } |