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| author | Joel Fernandes (Google) <joel@joelfernandes.org> | 2018-12-12 14:37:10 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.ibm.com> | 2019-01-25 15:35:24 -0800 |
| commit | 423a86a610cad121742ebe698ef98a3b4c87b5dd (patch) | |
| tree | 9117e80180d67b87476ba360d5f19505c783ae55 | |
| parent | c2d8089de7f0b849af11c271278fe6b904db5df2 (diff) | |
rcu: Add sparse check to rcu_assign_pointer()
The rcu_assign_pointer() function currently doesn't do any sparse checking
on the assigned-to pointer. So its possible that a pointer that is
not __rcu annotated is assigned with rcu_assign_pointer without sparse
complaints. Because rcu_dereference() already does such checking,
this commit makes rcu_assign_pointer() to do the same. The extra
error could be helpful in cases where an RCU pointer is assigned with
rcu_assign_pointer() but not annotated with __rcu.
This doesn't generate any code in the normal case because __CHECKER__ is
defined only in the context of sparse.
This commit also renames rcu_dereference_sparse() to rcu_check_parse()
since the checking now happens not only during derereferencing but also
during assignment.
Test: Introduced an rcu_assign_pointer in code and checked the output of
sparse with and without this change. The change correctly causes sparse
to throw an error.
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
| -rw-r--r-- | include/linux/rcupdate.h | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 6f8f047c4068..4a2cce4d4bd9 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -309,16 +309,16 @@ static inline void rcu_preempt_sleep_check(void) { } */ #ifdef __CHECKER__ -#define rcu_dereference_sparse(p, space) \ +#define rcu_check_sparse(p, space) \ ((void)(((typeof(*p) space *)p) == p)) #else /* #ifdef __CHECKER__ */ -#define rcu_dereference_sparse(p, space) +#define rcu_check_sparse(p, space) #endif /* #else #ifdef __CHECKER__ */ #define __rcu_access_pointer(p, space) \ ({ \ typeof(*p) *_________p1 = (typeof(*p) *__force)READ_ONCE(p); \ - rcu_dereference_sparse(p, space); \ + rcu_check_sparse(p, space); \ ((typeof(*p) __force __kernel *)(_________p1)); \ }) #define __rcu_dereference_check(p, c, space) \ @@ -326,13 +326,13 @@ static inline void rcu_preempt_sleep_check(void) { } /* Dependency order vs. p above. */ \ typeof(*p) *________p1 = (typeof(*p) *__force)READ_ONCE(p); \ RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_check() usage"); \ - rcu_dereference_sparse(p, space); \ + rcu_check_sparse(p, space); \ ((typeof(*p) __force __kernel *)(________p1)); \ }) #define __rcu_dereference_protected(p, c, space) \ ({ \ RCU_LOCKDEP_WARN(!(c), "suspicious rcu_dereference_protected() usage"); \ - rcu_dereference_sparse(p, space); \ + rcu_check_sparse(p, space); \ ((typeof(*p) __force __kernel *)(p)); \ }) #define rcu_dereference_raw(p) \ @@ -382,6 +382,7 @@ static inline void rcu_preempt_sleep_check(void) { } #define rcu_assign_pointer(p, v) \ ({ \ uintptr_t _r_a_p__v = (uintptr_t)(v); \ + rcu_check_sparse(p, __rcu); \ \ if (__builtin_constant_p(v) && (_r_a_p__v) == (uintptr_t)NULL) \ WRITE_ONCE((p), (typeof(p))(_r_a_p__v)); \ @@ -785,7 +786,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) */ #define RCU_INIT_POINTER(p, v) \ do { \ - rcu_dereference_sparse(p, __rcu); \ + rcu_check_sparse(p, __rcu); \ WRITE_ONCE(p, RCU_INITIALIZER(v)); \ } while (0) |