Tested-by: Jia Zhu <[email protected]>
在 2024/1/9 19:20, David Howells 写道:
> In __cachefiles_prepare_write(), the start and pos variables were made
> unsigned 64-bit so that the casts in the checking could be got rid of -
> which should be fine since absolute file offsets can't be negative, except
> that an error code may be obtained from vfs_llseek(), which *would* be
> negative. This breaks the error check.
>
> Fix this for now by reverting pos and start to be signed and putting back
> the casts. Unfortunately, the error value checks cannot be replaced with
> IS_ERR_VALUE() as long might be 32-bits.
>
> Fixes: 7097c96411d2 ("cachefiles: Fix __cachefiles_prepare_write()")
> Reported-by: Simon Horman <[email protected]>
> Reported-by: kernel test robot <[email protected]>
> Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
> Signed-off-by: David Howells <[email protected]>
> Reviewed-by: Simon Horman <[email protected]>
> cc: Gao Xiang <[email protected]>
> cc: Yiqun Leng <[email protected]>
> cc: Jia Zhu <[email protected]>
> cc: Jeff Layton <[email protected]>
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> ---
> fs/cachefiles/io.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c
> index 3eec26967437..9a2cb2868e90 100644
> --- a/fs/cachefiles/io.c
> +++ b/fs/cachefiles/io.c
> @@ -522,7 +522,7 @@ int __cachefiles_prepare_write(struct cachefiles_object *object,
> bool no_space_allocated_yet)
> {
> struct cachefiles_cache *cache = object->volume->cache;
> - unsigned long long start = *_start, pos;
> + loff_t start = *_start, pos;
> size_t len = *_len;
> int ret;
>
> @@ -556,7 +556,7 @@ int __cachefiles_prepare_write(struct cachefiles_object *object,
> cachefiles_trace_seek_error);
> return pos;
> }
> - if (pos >= start + *_len)
> + if ((u64)pos >= (u64)start + *_len)
> goto check_space; /* Unallocated region */
>
> /* We have a block that's at least partially filled - if we're low on
> @@ -575,7 +575,7 @@ int __cachefiles_prepare_write(struct cachefiles_object *object,
> cachefiles_trace_seek_error);
> return pos;
> }
> - if (pos >= start + *_len)
> + if ((u64)pos >= (u64)start + *_len)
> return 0; /* Fully allocated */
>
> /* Partially allocated, but insufficient space: cull. */
>