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Groups > linux.kernel > #1688911
| From | Elena Reshetova <elena.reshetova@intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 06/15] kernel: convert perf_event_context.refcount from atomic_t to refcount_t |
| Date | 2017-07-17 12:50 +0200 |
| Message-ID | <u4bLf-3Tv-65@gated-at.bofh.it> (permalink) |
| References | <u4bLb-3Tv-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
---
include/linux/perf_event.h | 3 ++-
kernel/events/core.c | 12 ++++++------
2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index a3b873f..f7a9802 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -54,6 +54,7 @@ struct perf_guest_info_callbacks {
#include <linux/perf_regs.h>
#include <linux/workqueue.h>
#include <linux/cgroup.h>
+#include <linux/refcount.h>
#include <asm/local.h>
struct perf_callchain_entry {
@@ -750,7 +751,7 @@ struct perf_event_context {
int nr_stat;
int nr_freq;
int rotate_disable;
- atomic_t refcount;
+ refcount_t refcount;
struct task_struct *task;
/*
diff --git a/kernel/events/core.c b/kernel/events/core.c
index dbb4f68..faf9925 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1109,7 +1109,7 @@ static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
static void get_ctx(struct perf_event_context *ctx)
{
- WARN_ON(!atomic_inc_not_zero(&ctx->refcount));
+ refcount_inc(&ctx->refcount);
}
static void free_ctx(struct rcu_head *head)
@@ -1123,7 +1123,7 @@ static void free_ctx(struct rcu_head *head)
static void put_ctx(struct perf_event_context *ctx)
{
- if (atomic_dec_and_test(&ctx->refcount)) {
+ if (refcount_dec_and_test(&ctx->refcount)) {
if (ctx->parent_ctx)
put_ctx(ctx->parent_ctx);
if (ctx->task && ctx->task != TASK_TOMBSTONE)
@@ -1201,7 +1201,7 @@ perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
again:
rcu_read_lock();
ctx = ACCESS_ONCE(event->ctx);
- if (!atomic_inc_not_zero(&ctx->refcount)) {
+ if (!refcount_inc_not_zero(&ctx->refcount)) {
rcu_read_unlock();
goto again;
}
@@ -1329,7 +1329,7 @@ perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
}
if (ctx->task == TASK_TOMBSTONE ||
- !atomic_inc_not_zero(&ctx->refcount)) {
+ !refcount_inc_not_zero(&ctx->refcount)) {
raw_spin_unlock(&ctx->lock);
ctx = NULL;
} else {
@@ -3760,7 +3760,7 @@ static void __perf_event_init_context(struct perf_event_context *ctx)
INIT_LIST_HEAD(&ctx->pinned_groups);
INIT_LIST_HEAD(&ctx->flexible_groups);
INIT_LIST_HEAD(&ctx->event_list);
- atomic_set(&ctx->refcount, 1);
+ refcount_set(&ctx->refcount, 1);
}
static struct perf_event_context *
@@ -9770,7 +9770,7 @@ __perf_event_ctx_lock_double(struct perf_event *group_leader,
again:
rcu_read_lock();
gctx = READ_ONCE(group_leader->ctx);
- if (!atomic_inc_not_zero(&gctx->refcount)) {
+ if (!refcount_inc_not_zero(&gctx->refcount)) {
rcu_read_unlock();
goto again;
}
--
2.7.4
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[PATCH 00/15] v3 kernel core pieces refcount conversions Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 07/15] kernel: convert ring_buffer.refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 02/15] kernel: convert signal_struct.sigcnt from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 04/15] kernel: convert task_struct.usage from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 13/15] sched: convert numa_group.refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 03/15] kernel: convert user_struct.__count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 09/15] kernel: convert uprobe.ref from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 14/15] kernel: convert futex_pi_state.refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
Re: [PATCH 14/15] kernel: convert futex_pi_state.refcount from atomic_t to refcount_t Thomas Gleixner <tglx@linutronix.de> - 2017-07-17 16:30 +0200
RE: [PATCH 14/15] kernel: convert futex_pi_state.refcount from atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-07-17 19:00 +0200
RE: [PATCH 14/15] kernel: convert futex_pi_state.refcount from atomic_t to refcount_t Thomas Gleixner <tglx@linutronix.de> - 2017-07-17 20:00 +0200
RE: [PATCH 14/15] kernel: convert futex_pi_state.refcount from atomic_t to refcount_t "Reshetova, Elena" <elena.reshetova@intel.com> - 2017-07-18 11:40 +0200
[PATCH 15/15] kernel: convert kcov.refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 10/15] kernel: convert nsproxy.count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 11/15] kernel: convert group_info.usage from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 01/15] kernel: convert sighand_struct.count from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 05/15] kernel: convert task_struct.stack_refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 06/15] kernel: convert perf_event_context.refcount from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
[PATCH 12/15] kernel: convert cred.usage from atomic_t to refcount_t Elena Reshetova <elena.reshetova@intel.com> - 2017-07-17 12:50 +0200
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