BUG at fs/afs/file.c:137!
Anton Blanchard
anton at samba.org
Wed Aug 26 23:43:58 EDT 2009
Hi David,
> Can you try the attached patch please?
Thanks! With the attached patch I can no longer hit it.
Anton
> David
> ---
> From: David Howells <dhowells at redhat.com>
> Subject: [PATCH] AFS: Stop readlink() on AFS crashing because file not passed to afs_readpage()
>
> kAFS crashes when asked to read a symbolic link because page_getlink() passes a
> NULL file pointer to read_mapping_page(), but afs_readpage() expects a file
> pointer from which to extract a key.
>
> Modify afs_readpage() to request the appropriate key from the calling
> process's keyrings if a file struct is not supplied with one attached.
>
> Signed-off-by: David Howells <dhowells at redhat.com>
> ---
>
> fs/afs/file.c | 18 +++++++++++++++---
> 1 files changed, 15 insertions(+), 3 deletions(-)
>
>
> diff --git a/fs/afs/file.c b/fs/afs/file.c
> index 1586496..cbc746d 100644
> --- a/fs/afs/file.c
> +++ b/fs/afs/file.c
> @@ -136,9 +136,16 @@ static int afs_readpage(struct file *file, struct page *page)
>
> inode = page->mapping->host;
>
> - ASSERT(file != NULL);
> - key = file->private_data;
> - ASSERT(key != NULL);
> + if (file) {
> + key = file->private_data;
> + ASSERT(key != NULL);
> + } else {
> + key = afs_request_key(AFS_FS_S(inode->i_sb)->volume->cell);
> + if (IS_ERR(key)) {
> + ret = PTR_ERR(key);
> + goto error_nokey;
> + }
> + }
>
> _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index);
>
> @@ -209,12 +216,17 @@ static int afs_readpage(struct file *file, struct page *page)
> unlock_page(page);
> }
>
> + if (!file)
> + key_put(key);
> _leave(" = 0");
> return 0;
>
> error:
> SetPageError(page);
> unlock_page(page);
> + if (!file)
> + key_put(key);
> +error_nokey:
> _leave(" = %d", ret);
> return ret;
> }
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