Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
sched_ext: Pass held rq to SCX_CALL_OP() for dump_cpu/dump_task
scx_dump_state() walks CPUs with rq_lock_irqsave() held and invokes
ops.dump_cpu / ops.dump_task with NULL locked_rq, leaving
scx_locked_rq_state NULL. If the BPF callback calls a kfunc that
re-acquires rq based on scx_locked_rq() - e.g. scx_bpf_cpuperf_set(cpu)
- it re-acquires the already-held rq.
Pass the held rq to SCX_CALL_OP(). Thread it into scx_dump_task() too.
The pre-loop ops.dump call runs before rq_lock_irqsave() so keeps
rq=NULL.
Fixes: 07814a9439a3 ("sched_ext: Print debug dump after an error exit")
Cc: stable@vger.kernel.org # v6.12+
Reported-by: Chris Mason <clm@meta.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
+6
-8
+6
-8
kernel/sched/ext.c
+6
-8
kernel/sched/ext.c
···
6117
6117
scx_dump_data.cpu = -1;
6118
6118
}
6119
6119
6120
-
static void scx_dump_task(struct scx_sched *sch,
6121
-
struct seq_buf *s, struct scx_dump_ctx *dctx,
6122
-
struct task_struct *p, char marker)
6120
+
static void scx_dump_task(struct scx_sched *sch, struct seq_buf *s, struct scx_dump_ctx *dctx,
6121
+
struct rq *rq, struct task_struct *p, char marker)
6123
6122
{
6124
6123
static unsigned long bt[SCX_EXIT_BT_LEN];
6125
6124
struct scx_sched *task_sch = scx_task_sched(p);
···
6159
6160
6160
6161
if (SCX_HAS_OP(sch, dump_task)) {
6161
6162
ops_dump_init(s, " ");
6162
-
SCX_CALL_OP(sch, dump_task, NULL, dctx, p);
6163
+
SCX_CALL_OP(sch, dump_task, rq, dctx, p);
6163
6164
ops_dump_exit();
6164
6165
}
6165
6166
···
6283
6284
used = seq_buf_used(&ns);
6284
6285
if (SCX_HAS_OP(sch, dump_cpu)) {
6285
6286
ops_dump_init(&ns, " ");
6286
-
SCX_CALL_OP(sch, dump_cpu, NULL,
6287
-
&dctx, cpu, idle);
6287
+
SCX_CALL_OP(sch, dump_cpu, rq, &dctx, cpu, idle);
6288
6288
ops_dump_exit();
6289
6289
}
6290
6290
···
6306
6308
6307
6309
if (rq->curr->sched_class == &ext_sched_class &&
6308
6310
(dump_all_tasks || scx_task_on_sched(sch, rq->curr)))
6309
-
scx_dump_task(sch, &s, &dctx, rq->curr, '*');
6311
+
scx_dump_task(sch, &s, &dctx, rq, rq->curr, '*');
6310
6312
6311
6313
list_for_each_entry(p, &rq->scx.runnable_list, scx.runnable_node)
6312
6314
if (dump_all_tasks || scx_task_on_sched(sch, p))
6313
-
scx_dump_task(sch, &s, &dctx, p, ' ');
6315
+
scx_dump_task(sch, &s, &dctx, rq, p, ' ');
6314
6316
next:
6315
6317
rq_unlock_irqrestore(rq, &rf);
6316
6318
}