[PATCH] smb/client: avoid possible NULL dereference in cifs_free_subrequest()

[Steve French]

Updated patch to change Fixes tag and Cc: David


On Fri, Aug 9, 2024 at 10:42 AM Steve French <smfrench at gmail.com> wrote:
>
> On Fri, Aug 9, 2024 at 10:11 AM Dan Carpenter <dan.carpenter at linaro.org> wrote:
> >
> > On Fri, Aug 09, 2024 at 06:00:26PM +0300, Dan Carpenter wrote:
> > > On Thu, Aug 08, 2024 at 08:23:32PM +0800, Su Hui wrote:
> > > > Clang static checker (scan-build) warning:
> > > >     cifsglob.h:line 890, column 3
> > > >     Access to field 'ops' results in a dereference of a null pointer.
> > > >
> > > > Commit 519be989717c ("cifs: Add a tracepoint to track credits involved in
> > > > R/W requests") adds a check for 'rdata->server', and let clang throw this
> > > > warning about NULL dereference.
> > > >
> > > > When 'rdata->credits.value != 0 && rdata->server == NULL' happens,
> > > > add_credits_and_wake_if() will call rdata->server->ops->add_credits().
> > > > This will cause NULL dereference problem. Add a check for 'rdata->server'
> > > > to avoid NULL dereference.
> > > >
> > > > Signed-off-by: Su Hui <suhui at nfschina.com>
> > >
> > > Needs a Fixes tag.
> > >
> > > Also when you add a Fixes tag, then get_maintainer will add the David Howells
> > > automatically.  I've added him manually.
> > >
> >
> > Actually, David should have been CC'd but the fixes tag wouldn't have pointed
> > to his patch.
> >
> > This is an inconsistent NULL checking warning.  It's not clear to me if the NULL
> > checks should be removed or more added.  If David were trying to fix a NULL
> > pointer dereference and accidentally left one unchecked dereference out then the
> > Fixes tag would point to his patch.  Since David was doing something unrelated
>
> Looks like (if this is even possible for server to to be null) then I
> will need to change
> the fixes to commit 69c3c023af25. I will update the tag in the current
> patch in for-next
>
> Author: David Howells <dhowells at redhat.com>
> Date:   Fri Oct 6 18:16:15 2023 +0100
>
>     cifs: Implement netfslib hooks
>
>     Provide implementation of the netfslib hooks that will be used by netfslib
>     to ask cifs to set up and perform operations.
> --
> Thanks,
>
> Steve



-- 
Thanks,

Steve
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