From: Song Liu <songliubraving@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Cc: <peterz@infradead.org>, <ast@kernel.org>, <daniel@iogearbox.net>,
<kernel-team@fb.com>, <john.fastabend@gmail.com>,
<kpsingh@chromium.org>, Song Liu <songliubraving@fb.com>,
Andrii Nakryiko <andriin@fb.com>
Subject: [PATCH v4 bpf-next 1/4] perf: expose get/put_callchain_entry()
Date: Sun, 28 Jun 2020 22:55:27 -0700 [thread overview]
Message-ID: <20200629055530.3244342-2-songliubraving@fb.com> (raw)
In-Reply-To: <20200629055530.3244342-1-songliubraving@fb.com>
Sanitize and expose get/put_callchain_entry(). This would be used by bpf
stack map.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
---
include/linux/perf_event.h | 2 ++
kernel/events/callchain.c | 13 ++++++-------
2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index b4bb32082342c..00ab5efa38334 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1244,6 +1244,8 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
extern struct perf_callchain_entry *perf_callchain(struct perf_event *event, struct pt_regs *regs);
extern int get_callchain_buffers(int max_stack);
extern void put_callchain_buffers(void);
+extern struct perf_callchain_entry *get_callchain_entry(int *rctx);
+extern void put_callchain_entry(int rctx);
extern int sysctl_perf_event_max_stack;
extern int sysctl_perf_event_max_contexts_per_stack;
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 334d48b16c36d..c6ce894e4ce94 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -149,7 +149,7 @@ void put_callchain_buffers(void)
}
}
-static struct perf_callchain_entry *get_callchain_entry(int *rctx)
+struct perf_callchain_entry *get_callchain_entry(int *rctx)
{
int cpu;
struct callchain_cpus_entries *entries;
@@ -159,8 +159,10 @@ static struct perf_callchain_entry *get_callchain_entry(int *rctx)
return NULL;
entries = rcu_dereference(callchain_cpus_entries);
- if (!entries)
+ if (!entries) {
+ put_recursion_context(this_cpu_ptr(callchain_recursion), *rctx);
return NULL;
+ }
cpu = smp_processor_id();
@@ -168,7 +170,7 @@ static struct perf_callchain_entry *get_callchain_entry(int *rctx)
(*rctx * perf_callchain_entry__sizeof()));
}
-static void
+void
put_callchain_entry(int rctx)
{
put_recursion_context(this_cpu_ptr(callchain_recursion), rctx);
@@ -183,11 +185,8 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
int rctx;
entry = get_callchain_entry(&rctx);
- if (rctx == -1)
- return NULL;
-
if (!entry)
- goto exit_put;
+ return NULL;
ctx.entry = entry;
ctx.max_stack = max_stack;
--
2.24.1
next prev parent reply other threads:[~2020-06-29 21:22 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-29 5:55 [PATCH v4 bpf-next 0/4] bpf: introduce bpf_get_task_stack() Song Liu
2020-06-29 5:55 ` Song Liu [this message]
2020-06-29 5:55 ` [PATCH v4 bpf-next 2/4] bpf: introduce helper bpf_get_task_stack() Song Liu
2020-06-30 4:18 ` Alexei Starovoitov
2020-06-30 6:12 ` Song Liu
2020-06-29 5:55 ` [PATCH v4 bpf-next 3/4] bpf: allow %pB in bpf_seq_printf() and bpf_trace_printk() Song Liu
2020-06-29 5:55 ` [PATCH v4 bpf-next 4/4] selftests/bpf: add bpf_iter test with bpf_get_task_stack() Song Liu
2020-06-29 15:06 ` Yonghong Song
2020-06-29 16:56 ` Song Liu
2020-06-29 18:22 ` Yonghong Song
2020-06-29 19:25 ` [PATCH v4 bpf-next 0/4] bpf: introduce bpf_get_task_stack() Andrii Nakryiko
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