github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-09-23 22:14:03 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

rcu-tasks: Apply READ_ONCE() and WRITE_ONCE() to fix data race

Browse Source 
Now that rcutorture tests readers from interrupt handlers, KCSAN spotted
an additional data race.  This commit therefore fixes it by applying
READ_ONCE() and WRITE_ONCE().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney 2026-07-12 10:50:08 -07:00
parent ef21090071
commit 647dd6e094
1 changed files with 8 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
include/linux/rcupdate_trace.h
View File

@ -95,10 +95,13 @@ static inline void rcu_read_unlock_tasks_trace(struct srcu_ctr __percpu *scp)
*/
static inline void rcu_read_lock_trace(void)
{
int n;
struct task_struct *t = current;
rcu_try_lock_acquire(&rcu_tasks_trace_srcu_struct.dep_map);
if (t->trc_reader_nesting++) {
n = READ_ONCE(t->trc_reader_nesting);
WRITE_ONCE(t->trc_reader_nesting, n + 1);
if (n) {
// In case we interrupted a Tasks Trace RCU reader.
return;
}
@ -119,12 +122,15 @@ static inline void rcu_read_lock_trace(void)
*/
static inline void rcu_read_unlock_trace(void)
{
int n;
struct srcu_ctr __percpu *scp;
struct task_struct *t = current;
scp = t->trc_reader_scp;
barrier(); // scp before nesting to protect against interrupt handler.
if (!--t->trc_reader_nesting) {
n = READ_ONCE(t->trc_reader_nesting) - 1;
WRITE_ONCE(t->trc_reader_nesting, n);
if (!n) {
if (!IS_ENABLED(CONFIG_TASKS_TRACE_RCU_NO_MB))
smp_mb(); // Placeholder for more selective ordering
__srcu_read_unlock_fast(&rcu_tasks_trace_srcu_struct, scp);