From: Masami Hiramatsu <mhiramat@kernel.org>
To: Brendan Gregg <brendan.d.gregg@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Alexei Starovoitov <ast@kernel.org>
Cc: mhiramat@kernel.org, Ingo Molnar <mingo@kernel.org>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
Daniel Borkmann <daniel@iogearbox.net>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
"David S . Miller" <davem@davemloft.net>,
paulmck@kernel.org, joel@joelfernandes.org,
"Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Subject: [RFT PATCH 07/13] kprobes: Use normal list traversal API if a mutex is held
Date: Thu, 16 Jan 2020 23:45:23 +0900 [thread overview]
Message-ID: <157918592332.29301.1564446199611592837.stgit@devnote2> (raw)
In-Reply-To: <157918584866.29301.6941815715391411338.stgit@devnote2>
Use normal list traversal API instead of rcu_read_lock,
RCU list traversal and rcu_read_unlock pair if a mutex
which protects the list is held in the methods of
kprobe_insn_cache.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
kernel/kprobes.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 848c14e92ccc..09b0e33bc845 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -141,8 +141,7 @@ kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
/* Since the slot array is not protected by rcu, we need a mutex */
mutex_lock(&c->mutex);
retry:
- rcu_read_lock();
- list_for_each_entry_rcu(kip, &c->pages, list) {
+ list_for_each_entry(kip, &c->pages, list) {
if (kip->nused < slots_per_page(c)) {
int i;
for (i = 0; i < slots_per_page(c); i++) {
@@ -150,7 +149,6 @@ kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
kip->slot_used[i] = SLOT_USED;
kip->nused++;
slot = kip->insns + (i * c->insn_size);
- rcu_read_unlock();
goto out;
}
}
@@ -159,7 +157,6 @@ kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
WARN_ON(1);
}
}
- rcu_read_unlock();
/* If there are any garbage slots, collect it and try again. */
if (c->nr_garbage && collect_garbage_slots(c) == 0)
@@ -244,8 +241,7 @@ void __free_insn_slot(struct kprobe_insn_cache *c,
long idx;
mutex_lock(&c->mutex);
- rcu_read_lock();
- list_for_each_entry_rcu(kip, &c->pages, list) {
+ list_for_each_entry(kip, &c->pages, list) {
idx = ((long)slot - (long)kip->insns) /
(c->insn_size * sizeof(kprobe_opcode_t));
if (idx >= 0 && idx < slots_per_page(c))
@@ -255,7 +251,6 @@ void __free_insn_slot(struct kprobe_insn_cache *c,
WARN_ON(1);
kip = NULL;
out:
- rcu_read_unlock();
/* Mark and sweep: this may sleep */
if (kip) {
/* Check double free */
next prev parent reply other threads:[~2020-01-16 14:45 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-16 14:44 [RFT PATCH 00/13] tracing: kprobes: Introduce async unregistration Masami Hiramatsu
2020-01-16 14:44 ` [RFT PATCH 01/13] kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex Masami Hiramatsu
2020-01-16 14:44 ` [RFT PATCH 02/13] kprobes: Remove redundant arch_disarm_kprobe() call Masami Hiramatsu
2020-01-16 14:44 ` [RFT PATCH 03/13] kprobes: Postpone optimizer until a bunch of probes (un)registered Masami Hiramatsu
2020-01-16 14:44 ` [RFT PATCH 04/13] kprobes: Make optimizer delay to 1 second Masami Hiramatsu
2020-01-22 0:29 ` Steven Rostedt
2020-01-22 7:23 ` Masami Hiramatsu
2020-01-22 12:11 ` Steven Rostedt
2020-01-22 13:12 ` Masami Hiramatsu
2020-01-22 16:54 ` Paul E. McKenney
2020-01-23 1:33 ` Masami Hiramatsu
2020-01-23 2:26 ` Paul E. McKenney
2020-01-23 6:13 ` Masami Hiramatsu
2020-01-23 10:03 ` Paul E. McKenney
2020-01-16 14:45 ` [RFT PATCH 05/13] tracing/kprobe: Use call_rcu to defer freeing event_file_link Masami Hiramatsu
2020-01-27 15:02 ` kbuild test robot
2020-01-27 15:02 ` [RFC PATCH] tracing/kprobe: trace_kprobe_disabled_finished can be static kbuild test robot
2020-01-28 15:02 ` Masami Hiramatsu
2020-01-16 14:45 ` [RFT PATCH 06/13] kprobes: Enable kprobe-booster with CONFIG_PREEMPT=y Masami Hiramatsu
2020-01-16 14:45 ` Masami Hiramatsu [this message]
2020-01-16 14:45 ` [RFT PATCH 08/13] kprobes: Use workqueue for reclaiming kprobe insn cache pages Masami Hiramatsu
2020-01-16 14:45 ` [RFT PATCH 09/13] kprobes: Free kprobe_insn_page asynchronously Masami Hiramatsu
2020-01-16 14:45 ` [RFT PATCH 10/13] kprobes: Make free_*insn_slot() mutex-less Masami Hiramatsu
2020-01-16 14:46 ` [RFT PATCH 11/13] kprobes: Add asynchronous unregistration APIs Masami Hiramatsu
2020-01-16 14:46 ` [RFT PATCH 12/13] tracing/kprobe: Free probe event asynchronously Masami Hiramatsu
2020-01-16 14:46 ` [RFT PATCH 13/13] tracing/kprobe: perf_event: Remove local kprobe " Masami Hiramatsu
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