2022-05-28 19:44:13

by Tom Rix

Subject: [PATCH] cifs: set length when cifs_copy_pages_to_iter is successful

clang build fails with
fs/cifs/smb2ops.c:4984:7: error: variable 'length' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
if (rdata->result != 0) {
^~~~~~~~~~~~~~~~~~

handle_read_data() returns the number of bytes handled by setting the length variable.
This only happens in the copy_to_iter() branch, it needs to also happen in the
cifs_copy_pages_to_iter() branch. When cifs_copy_pages_to_iter() is successful,
its parameter data_len is how many bytes were handled, so set length to data_len.

Fixes: 67fd8cff2b0f ("cifs: Change the I/O paths to use an iterator rather than a page list")
Signed-off-by: Tom Rix <[email protected]>
---
fs/cifs/smb2ops.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 3630e132781f..bfad482ec186 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -4988,7 +4988,7 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
dequeue_mid(mid, rdata->result);
return 0;
}
- rdata->got_bytes = pages_len;
+ length = rdata->got_bytes = pages_len;

} else if (buf_len >= data_offset + data_len) {
/* read response payload is in buf */
--
2.27.0

2022-05-28 20:44:00

by Nick Desaulniers

Subject: Re: [PATCH] cifs: set length when cifs_copy_pages_to_iter is successful

+ Steve's @microsoft.com email addr.

On Thu, May 26, 2022 at 7:02 AM Tom Rix <[email protected]> wrote:
>
> clang build fails with
> fs/cifs/smb2ops.c:4984:7: error: variable 'length' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
> if (rdata->result != 0) {
> ^~~~~~~~~~~~~~~~~~
>
> handle_read_data() returns the number of bytes handled by setting the length variable.
> This only happens in the copy_to_iter() branch, it needs to also happen in the
> cifs_copy_pages_to_iter() branch. When cifs_copy_pages_to_iter() is successful,
> its parameter data_len is how many bytes were handled, so set length to data_len.
>
> Fixes: 67fd8cff2b0f ("cifs: Change the I/O paths to use an iterator rather than a page list")
> Signed-off-by: Tom Rix <[email protected]>
> ---
> fs/cifs/smb2ops.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index 3630e132781f..bfad482ec186 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -4988,7 +4988,7 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
> dequeue_mid(mid, rdata->result);
> return 0;
> }
> - rdata->got_bytes = pages_len;
> + length = rdata->got_bytes = pages_len;
>
> } else if (buf_len >= data_offset + data_len) {
> /* read response payload is in buf */
> --
> 2.27.0
>


--
Thanks,
~Nick Desaulniers

2022-05-28 23:32:43

by Steve French

Subject: Re: [PATCH] cifs: set length when cifs_copy_pages_to_iter is successful

Presumably this was in Dave Howell's patch set which we took out of
for-next to restructure in some of Al's feedback and some things found
during testing. So nothing to fix in current mainline or for-next ...
right?

On Sat, May 28, 2022 at 3:40 PM Nick Desaulniers
<[email protected]> wrote:
>
> + Steve's @microsoft.com email addr.
>
> On Thu, May 26, 2022 at 7:02 AM Tom Rix <[email protected]> wrote:
> >
> > clang build fails with
> > fs/cifs/smb2ops.c:4984:7: error: variable 'length' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
> > if (rdata->result != 0) {
> > ^~~~~~~~~~~~~~~~~~
> >
> > handle_read_data() returns the number of bytes handled by setting the length variable.
> > This only happens in the copy_to_iter() branch, it needs to also happen in the
> > cifs_copy_pages_to_iter() branch. When cifs_copy_pages_to_iter() is successful,
> > its parameter data_len is how many bytes were handled, so set length to data_len.
> >
> > Fixes: 67fd8cff2b0f ("cifs: Change the I/O paths to use an iterator rather than a page list")
> > Signed-off-by: Tom Rix <[email protected]>
> > ---
> > fs/cifs/smb2ops.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> > index 3630e132781f..bfad482ec186 100644
> > --- a/fs/cifs/smb2ops.c
> > +++ b/fs/cifs/smb2ops.c
> > @@ -4988,7 +4988,7 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
> > dequeue_mid(mid, rdata->result);
> > return 0;
> > }
> > - rdata->got_bytes = pages_len;
> > + length = rdata->got_bytes = pages_len;
> >
> > } else if (buf_len >= data_offset + data_len) {
> > /* read response payload is in buf */
> > --
> > 2.27.0
> >
>
>
> --
> Thanks,
> ~Nick Desaulniers



--
Thanks,

Steve

2022-05-29 18:01:44

by Tom Rix

Subject: Re: [PATCH] cifs: set length when cifs_copy_pages_to_iter is successful

On 5/28/22 4:31 PM, Steve French wrote:
> Presumably this was in Dave Howell's patch set which we took out of
> for-next to restructure in some of Al's feedback and some things found
> during testing. So nothing to fix in current mainline or for-next ...
> right?

Yup. Nothing to fix.

So drop this patch.

Tom

>
> On Sat, May 28, 2022 at 3:40 PM Nick Desaulniers
> <[email protected]> wrote:
>> + Steve's @microsoft.com email addr.
>>
>> On Thu, May 26, 2022 at 7:02 AM Tom Rix <[email protected]> wrote:
>>> clang build fails with
>>> fs/cifs/smb2ops.c:4984:7: error: variable 'length' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
>>> if (rdata->result != 0) {
>>> ^~~~~~~~~~~~~~~~~~
>>>
>>> handle_read_data() returns the number of bytes handled by setting the length variable.
>>> This only happens in the copy_to_iter() branch, it needs to also happen in the
>>> cifs_copy_pages_to_iter() branch. When cifs_copy_pages_to_iter() is successful,
>>> its parameter data_len is how many bytes were handled, so set length to data_len.
>>>
>>> Fixes: 67fd8cff2b0f ("cifs: Change the I/O paths to use an iterator rather than a page list")
>>> Signed-off-by: Tom Rix <[email protected]>
>>> ---
>>> fs/cifs/smb2ops.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
>>> index 3630e132781f..bfad482ec186 100644
>>> --- a/fs/cifs/smb2ops.c
>>> +++ b/fs/cifs/smb2ops.c
>>> @@ -4988,7 +4988,7 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
>>> dequeue_mid(mid, rdata->result);
>>> return 0;
>>> }
>>> - rdata->got_bytes = pages_len;
>>> + length = rdata->got_bytes = pages_len;
>>>
>>> } else if (buf_len >= data_offset + data_len) {
>>> /* read response payload is in buf */
>>> --
>>> 2.27.0
>>>
>>
>> --
>> Thanks,
>> ~Nick Desaulniers
>
>