| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <9d7a9f37-f037-00b8-afd3-72bb840a90df@amd.com>
Date: Tue, 6 Sep 2022 11:20:53 +0530
From: Ravi Bangoria <ravi.bangoria@....com>
To: peterz@...radead.org
Cc: acme@...nel.org, alexander.shishkin@...ux.intel.com,
jolsa@...hat.com, namhyung@...nel.org, songliubraving@...com,
eranian@...gle.com, ak@...ux.intel.com, mark.rutland@....com,
frederic@...nel.org, maddy@...ux.ibm.com, irogers@...gle.com,
will@...nel.org, robh@...nel.org, mingo@...hat.com,
catalin.marinas@....com, linux-arm-kernel@...ts.infradead.org,
linux-perf-users@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
linux-s390@...r.kernel.org, linux-kernel@...r.kernel.org,
sandipan.das@....com, ananth.narayan@....com, kim.phillips@....com,
santosh.shukla@....com, ravi.bangoria@....com
Subject: Re: [PATCH] perf: Rewrite core context handling
> @@ -9752,10 +9889,13 @@ void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
> struct trace_entry *entry = record;
>
> rcu_read_lock();
> - ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
> + ctx = rcu_dereference(task->perf_event_ctxp);
> if (!ctx)
> goto unlock;
>
> + // XXX iterate groups instead, we should be able to
> + // find the subtree for the perf_tracepoint pmu and CPU.
> +
> list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
> if (event->cpu != smp_processor_id())
> continue;
This one was simple enough so I prepared a patch for this. Let
me know if you see any issues with below diff.
---
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 820c56c66b26..e0232e0bb74e 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9807,6 +9807,44 @@ static struct pmu perf_swevent = {
#ifdef CONFIG_EVENT_TRACING
+static void tp_perf_event_destroy(struct perf_event *event)
+{
+ perf_trace_destroy(event);
+}
+
+static int perf_tp_event_init(struct perf_event *event)
+{
+ int err;
+
+ if (event->attr.type != PERF_TYPE_TRACEPOINT)
+ return -ENOENT;
+
+ /*
+ * no branch sampling for tracepoint events
+ */
+ if (has_branch_stack(event))
+ return -EOPNOTSUPP;
+
+ err = perf_trace_init(event);
+ if (err)
+ return err;
+
+ event->destroy = tp_perf_event_destroy;
+
+ return 0;
+}
+
+static struct pmu perf_tracepoint = {
+ .task_ctx_nr = perf_sw_context,
+
+ .event_init = perf_tp_event_init,
+ .add = perf_trace_add,
+ .del = perf_trace_del,
+ .start = perf_swevent_start,
+ .stop = perf_swevent_stop,
+ .read = perf_swevent_read,
+};
+
static int perf_tp_filter_match(struct perf_event *event,
struct perf_sample_data *data)
{
@@ -9856,6 +9894,49 @@ void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
}
EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
+
+static void __perf_tp_event_target_task(u64 count, void *record,
+ struct pt_regs *regs,
+ struct perf_sample_data *data,
+ struct perf_event *event)
+{
+ struct trace_entry *entry = record;
+
+ if (event->attr.config != entry->type)
+ return;
+ /* Cannot deliver synchronous signal to other task. */
+ if (event->attr.sigtrap)
+ return;
+ if (perf_tp_event_match(event, data, regs))
+ perf_swevent_event(event, count, data, regs);
+}
+
+static void perf_tp_event_target_task(u64 count, void *record,
+ struct pt_regs *regs,
+ struct perf_sample_data *data,
+ struct perf_event_context *ctx)
+{
+ struct perf_event *event, *sibling;
+
+ event = perf_event_groups_first(&ctx->pinned_groups, smp_processor_id(),
+ &perf_tracepoint, NULL);
+ for (; event; event = perf_event_groups_next(event, &perf_tracepoint)) {
+ __perf_tp_event_target_task(count, record, regs, data, event);
+ for_each_sibling_event(sibling, event) {
+ __perf_tp_event_target_task(count, record, regs, data, sibling);
+ }
+ }
+
+ event = perf_event_groups_first(&ctx->flexible_groups, smp_processor_id(),
+ &perf_tracepoint, NULL);
+ for (; event; event = perf_event_groups_next(event, &perf_tracepoint)) {
+ __perf_tp_event_target_task(count, record, regs, data, event);
+ for_each_sibling_event(sibling, event) {
+ __perf_tp_event_target_task(count, record, regs, data, sibling);
+ }
+ }
+}
+
void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
struct pt_regs *regs, struct hlist_head *head, int rctx,
struct task_struct *task)
@@ -9886,29 +9967,15 @@ void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
*/
if (task && task != current) {
struct perf_event_context *ctx;
- struct trace_entry *entry = record;
rcu_read_lock();
ctx = rcu_dereference(task->perf_event_ctxp);
if (!ctx)
goto unlock;
- // XXX iterate groups instead, we should be able to
- // find the subtree for the perf_tracepoint pmu and CPU.
-
- list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
- if (event->cpu != smp_processor_id())
- continue;
- if (event->attr.type != PERF_TYPE_TRACEPOINT)
- continue;
- if (event->attr.config != entry->type)
- continue;
- /* Cannot deliver synchronous signal to other task. */
- if (event->attr.sigtrap)
- continue;
- if (perf_tp_event_match(event, &data, regs))
- perf_swevent_event(event, count, &data, regs);
- }
+ raw_spin_lock(&ctx->lock);
+ perf_tp_event_target_task(count, record, regs, &data, ctx);
+ raw_spin_unlock(&ctx->lock);
unlock:
rcu_read_unlock();
}
@@ -9917,44 +9984,6 @@ void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
}
EXPORT_SYMBOL_GPL(perf_tp_event);
-static void tp_perf_event_destroy(struct perf_event *event)
-{
- perf_trace_destroy(event);
-}
-
-static int perf_tp_event_init(struct perf_event *event)
-{
- int err;
-
- if (event->attr.type != PERF_TYPE_TRACEPOINT)
- return -ENOENT;
-
- /*
- * no branch sampling for tracepoint events
- */
- if (has_branch_stack(event))
- return -EOPNOTSUPP;
-
- err = perf_trace_init(event);
- if (err)
- return err;
-
- event->destroy = tp_perf_event_destroy;
-
- return 0;
-}
-
-static struct pmu perf_tracepoint = {
- .task_ctx_nr = perf_sw_context,
-
- .event_init = perf_tp_event_init,
- .add = perf_trace_add,
- .del = perf_trace_del,
- .start = perf_swevent_start,
- .stop = perf_swevent_stop,
- .read = perf_swevent_read,
-};
-
#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
/*
* Flags in config, used by dynamic PMU kprobe and uprobe
---
Powered by blists - more mailing lists