* [PATCH tip/core/rcu 1/3] rcu: Record kvfree_call_rcu() call stack for KASAN
2021-01-06 1:01 [PATCH tip/core/rcu 0/3] kfree_rcu() updates for v5.12 Paul E. McKenney
@ 2021-01-06 1:01 ` paulmck
2021-01-06 1:01 ` [PATCH tip/core/rcu 2/3] rcu: Introduce kfree_rcu() single-argument macro paulmck
2021-01-06 1:01 ` [PATCH tip/core/rcu 3/3] rcu: Eliminate the __kvfree_rcu() macro paulmck
2 siblings, 0 replies; 4+ messages in thread
From: paulmck @ 2021-01-06 1:01 UTC (permalink / raw)
To: rcu
Cc: linux-kernel, kernel-team, mingo, jiangshanlai, akpm,
mathieu.desnoyers, josh, tglx, peterz, rostedt, dhowells,
edumazet, fweisbec, oleg, joel, Zqiang, Paul E . McKenney
From: Zqiang <qiang.zhang@windriver.com>
This commit adds a call to kasan_record_aux_stack() in kvfree_call_rcu()
in order to record the call stack of the code that caused the object
to be freed. Please note that this function does not update the
allocated/freed state, which is important because RCU readers might
still be referencing this object.
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Zqiang <qiang.zhang@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tree.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 40e5e3d..2db736c 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3498,6 +3498,7 @@ void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
goto unlock_return;
}
+ kasan_record_aux_stack(ptr);
success = kvfree_call_rcu_add_ptr_to_bulk(krcp, ptr);
if (!success) {
run_page_cache_worker(krcp);
--
2.9.5
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH tip/core/rcu 2/3] rcu: Introduce kfree_rcu() single-argument macro
2021-01-06 1:01 [PATCH tip/core/rcu 0/3] kfree_rcu() updates for v5.12 Paul E. McKenney
2021-01-06 1:01 ` [PATCH tip/core/rcu 1/3] rcu: Record kvfree_call_rcu() call stack for KASAN paulmck
@ 2021-01-06 1:01 ` paulmck
2021-01-06 1:01 ` [PATCH tip/core/rcu 3/3] rcu: Eliminate the __kvfree_rcu() macro paulmck
2 siblings, 0 replies; 4+ messages in thread
From: paulmck @ 2021-01-06 1:01 UTC (permalink / raw)
To: rcu
Cc: linux-kernel, kernel-team, mingo, jiangshanlai, akpm,
mathieu.desnoyers, josh, tglx, peterz, rostedt, dhowells,
edumazet, fweisbec, oleg, joel, Uladzislau Rezki (Sony),
Paul E . McKenney
From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
There is a kvfree_rcu() single argument macro that handles pointers
returned by kvmalloc(). Even though it also handles pointer returned by
kmalloc(), readability suffers.
This commit therefore updates the kfree_rcu() macro to explicitly pair
with kmalloc(), thus improving readability.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
include/linux/rcupdate.h | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index de08264..b95373e 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -851,8 +851,9 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
/**
* kfree_rcu() - kfree an object after a grace period.
- * @ptr: pointer to kfree
- * @rhf: the name of the struct rcu_head within the type of @ptr.
+ * @ptr: pointer to kfree for both single- and double-argument invocations.
+ * @rhf: the name of the struct rcu_head within the type of @ptr,
+ * but only for double-argument invocations.
*
* Many rcu callbacks functions just call kfree() on the base structure.
* These functions are trivial, but their size adds up, and furthermore
@@ -875,13 +876,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
* The BUILD_BUG_ON check must not involve any function calls, hence the
* checks are done in macros here.
*/
-#define kfree_rcu(ptr, rhf) \
-do { \
- typeof (ptr) ___p = (ptr); \
- \
- if (___p) \
- __kvfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \
-} while (0)
+#define kfree_rcu kvfree_rcu
/**
* kvfree_rcu() - kvfree an object after a grace period.
@@ -913,7 +908,14 @@ do { \
kvfree_rcu_arg_2, kvfree_rcu_arg_1)(__VA_ARGS__)
#define KVFREE_GET_MACRO(_1, _2, NAME, ...) NAME
-#define kvfree_rcu_arg_2(ptr, rhf) kfree_rcu(ptr, rhf)
+#define kvfree_rcu_arg_2(ptr, rhf) \
+do { \
+ typeof (ptr) ___p = (ptr); \
+ \
+ if (___p) \
+ __kvfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \
+} while (0)
+
#define kvfree_rcu_arg_1(ptr) \
do { \
typeof(ptr) ___p = (ptr); \
--
2.9.5
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH tip/core/rcu 3/3] rcu: Eliminate the __kvfree_rcu() macro
2021-01-06 1:01 [PATCH tip/core/rcu 0/3] kfree_rcu() updates for v5.12 Paul E. McKenney
2021-01-06 1:01 ` [PATCH tip/core/rcu 1/3] rcu: Record kvfree_call_rcu() call stack for KASAN paulmck
2021-01-06 1:01 ` [PATCH tip/core/rcu 2/3] rcu: Introduce kfree_rcu() single-argument macro paulmck
@ 2021-01-06 1:01 ` paulmck
2 siblings, 0 replies; 4+ messages in thread
From: paulmck @ 2021-01-06 1:01 UTC (permalink / raw)
To: rcu
Cc: linux-kernel, kernel-team, mingo, jiangshanlai, akpm,
mathieu.desnoyers, josh, tglx, peterz, rostedt, dhowells,
edumazet, fweisbec, oleg, joel, Uladzislau Rezki (Sony),
Paul E . McKenney
From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
This commit open-codes the __kvfree_rcu() macro, thus saving a
few lines of code and improving readability.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
include/linux/rcupdate.h | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index b95373e..f1576cd 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -840,15 +840,6 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
*/
#define __is_kvfree_rcu_offset(offset) ((offset) < 4096)
-/*
- * Helper macro for kfree_rcu() to prevent argument-expansion eyestrain.
- */
-#define __kvfree_rcu(head, offset) \
- do { \
- BUILD_BUG_ON(!__is_kvfree_rcu_offset(offset)); \
- kvfree_call_rcu(head, (rcu_callback_t)(unsigned long)(offset)); \
- } while (0)
-
/**
* kfree_rcu() - kfree an object after a grace period.
* @ptr: pointer to kfree for both single- and double-argument invocations.
@@ -866,7 +857,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
* Because the functions are not allowed in the low-order 4096 bytes of
* kernel virtual memory, offsets up to 4095 bytes can be accommodated.
* If the offset is larger than 4095 bytes, a compile-time error will
- * be generated in __kvfree_rcu(). If this error is triggered, you can
+ * be generated in kvfree_rcu_arg_2(). If this error is triggered, you can
* either fall back to use of call_rcu() or rearrange the structure to
* position the rcu_head structure into the first 4096 bytes.
*
@@ -912,8 +903,11 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
do { \
typeof (ptr) ___p = (ptr); \
\
- if (___p) \
- __kvfree_rcu(&((___p)->rhf), offsetof(typeof(*(ptr)), rhf)); \
+ if (___p) { \
+ BUILD_BUG_ON(!__is_kvfree_rcu_offset(offsetof(typeof(*(ptr)), rhf))); \
+ kvfree_call_rcu(&((___p)->rhf), (rcu_callback_t)(unsigned long) \
+ (offsetof(typeof(*(ptr)), rhf))); \
+ } \
} while (0)
#define kvfree_rcu_arg_1(ptr) \
--
2.9.5
^ permalink raw reply related [flat|nested] 4+ messages in thread