| Message ID | 20110807174829.GY2203@ZenIV.linux.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sun, Aug 7, 2011 at 12:48 PM, Al Viro <viro@zeniv.linux.org.uk> wrote: > On Sun, Aug 07, 2011 at 11:22:51AM -0500, Steve French wrote: >> I noticed a series of sparse warnings (on all calls to cifs's GetXid >> after building on a newly install fc15 system (yum installed a sparse >> binary dated June 23). >> >> fs/cifs/cifsfs.c:168:15: warning: dereference of noderef expression >> fs/cifs/cifsfs.c:542:15: warning: dereference of noderef expression >> >> Has sparse changed to add a new warning - I see (from quick search) >> others getting this on other modules years ago, but I didn't see >> anything obvious wrong with the definition of the function, and I >> hadn't noticed sparse complaining about it before, and would like to >> remove the 50+ new messages as they clutter the build output. > > It's not sparse change - the whinge comes from current_fsuid(), i.e. direct > read of current->cred, even though it's declared with __rcu. The thing is, > current->cred does *not* need rcu_dereference() - only the task itself > can change it. Easily fixed... your change makes sense - thx Steve -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/cred.h b/include/linux/cred.h index 48e82af..98f46ef 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -265,10 +265,11 @@ static inline void put_cred(const struct cred *_cred) /** * current_cred - Access the current task's subjective credentials * - * Access the subjective credentials of the current task. + * Access the subjective credentials of the current task. RCU-safe, + * since nobody else can modify it. */ #define current_cred() \ - (current->cred) + (*(__force struct cred **)¤t->cred) /** * __task_cred - Access a task's objective credentials @@ -307,7 +308,7 @@ static inline void put_cred(const struct cred *_cred) ({ \ struct user_struct *__u; \ struct cred *__cred; \ - __cred = (struct cred *) current_cred(); \ + __cred = current_cred(); \ __u = get_uid(__cred->user); \ __u; \ }) @@ -322,7 +323,7 @@ static inline void put_cred(const struct cred *_cred) ({ \ struct group_info *__groups; \ struct cred *__cred; \ - __cred = (struct cred *) current_cred(); \ + __cred = current_cred(); \ __groups = get_group_info(__cred->group_info); \ __groups; \ }) @@ -341,7 +342,7 @@ static inline void put_cred(const struct cred *_cred) #define current_cred_xxx(xxx) \ ({ \ - current->cred->xxx; \ + current_cred()->xxx; \ }) #define current_uid() (current_cred_xxx(uid))