From: Elena Reshetova <elena.reshetova@intel.com> To: mingo@redhat.com Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, viro@zeniv.linux.org.uk, tj@kernel.org, hannes@cmpxchg.org, lizefan@huawei.com, acme@kernel.org, alexander.shishkin@linux.intel.com, eparis@redhat.com, akpm@linux-foundation.org, arnd@arndb.de, luto@kernel.org, keescook@chromium.org, tglx@linutronix.de, dvhart@infradead.org, ebiederm@xmission.com, linux-mm@kvack.org, axboe@kernel.dk, Elena Reshetova <elena.reshetova@intel.com> Subject: [PATCH 08/15] perf/ring_buffer: convert ring_buffer.refcount to refcount_t Date: Fri, 20 Oct 2017 15:15:50 +0300 [thread overview] Message-ID: <1508501757-15784-9-git-send-email-elena.reshetova@intel.com> (raw) In-Reply-To: <1508501757-15784-1-git-send-email-elena.reshetova@intel.com> atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable ring_buffer.refcount is used as pure reference counter. Convert it to refcount_t and fix up the operations. 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> --- kernel/events/core.c | 4 ++-- kernel/events/internal.h | 3 ++- kernel/events/ring_buffer.c | 2 +- 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 7272b47..66d7e18 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5107,7 +5107,7 @@ struct ring_buffer *ring_buffer_get(struct perf_event *event) rcu_read_lock(); rb = rcu_dereference(event->rb); if (rb) { - if (!atomic_inc_not_zero(&rb->refcount)) + if (!refcount_inc_not_zero(&rb->refcount)) rb = NULL; } rcu_read_unlock(); @@ -5117,7 +5117,7 @@ struct ring_buffer *ring_buffer_get(struct perf_event *event) void ring_buffer_put(struct ring_buffer *rb) { - if (!atomic_dec_and_test(&rb->refcount)) + if (!refcount_dec_and_test(&rb->refcount)) return; WARN_ON_ONCE(!list_empty(&rb->event_list)); diff --git a/kernel/events/internal.h b/kernel/events/internal.h index 843e970..1cdd9fa 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -3,13 +3,14 @@ #include <linux/hardirq.h> #include <linux/uaccess.h> +#include <linux/refcount.h> /* Buffer handling */ #define RING_BUFFER_WRITABLE 0x01 struct ring_buffer { - atomic_t refcount; + refcount_t refcount; struct rcu_head rcu_head; #ifdef CONFIG_PERF_USE_VMALLOC struct work_struct work; diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index f684d8e..86e1379 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -284,7 +284,7 @@ ring_buffer_init(struct ring_buffer *rb, long watermark, int flags) else rb->overwrite = 1; - atomic_set(&rb->refcount, 1); + refcount_set(&rb->refcount, 1); INIT_LIST_HEAD(&rb->event_list); spin_lock_init(&rb->event_lock); -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: Elena Reshetova <elena.reshetova@intel.com> To: mingo@redhat.com Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, viro@zeniv.linux.org.uk, tj@kernel.org, hannes@cmpxchg.org, lizefan@huawei.com, acme@kernel.org, alexander.shishkin@linux.intel.com, eparis@redhat.com, akpm@linux-foundation.org, arnd@arndb.de, luto@kernel.org, keescook@chromium.org, tglx@linutronix.de, dvhart@infradead.org, ebiederm@xmission.com, linux-mm@kvack.org, axboe@kernel.dk, Elena Reshetova <elena.reshetova@intel.com> Subject: [PATCH 08/15] perf/ring_buffer: convert ring_buffer.refcount to refcount_t Date: Fri, 20 Oct 2017 15:15:50 +0300 [thread overview] Message-ID: <1508501757-15784-9-git-send-email-elena.reshetova@intel.com> (raw) In-Reply-To: <1508501757-15784-1-git-send-email-elena.reshetova@intel.com> atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable ring_buffer.refcount is used as pure reference counter. Convert it to refcount_t and fix up the operations. 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> --- kernel/events/core.c | 4 ++-- kernel/events/internal.h | 3 ++- kernel/events/ring_buffer.c | 2 +- 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 7272b47..66d7e18 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5107,7 +5107,7 @@ struct ring_buffer *ring_buffer_get(struct perf_event *event) rcu_read_lock(); rb = rcu_dereference(event->rb); if (rb) { - if (!atomic_inc_not_zero(&rb->refcount)) + if (!refcount_inc_not_zero(&rb->refcount)) rb = NULL; } rcu_read_unlock(); @@ -5117,7 +5117,7 @@ struct ring_buffer *ring_buffer_get(struct perf_event *event) void ring_buffer_put(struct ring_buffer *rb) { - if (!atomic_dec_and_test(&rb->refcount)) + if (!refcount_dec_and_test(&rb->refcount)) return; WARN_ON_ONCE(!list_empty(&rb->event_list)); diff --git a/kernel/events/internal.h b/kernel/events/internal.h index 843e970..1cdd9fa 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -3,13 +3,14 @@ #include <linux/hardirq.h> #include <linux/uaccess.h> +#include <linux/refcount.h> /* Buffer handling */ #define RING_BUFFER_WRITABLE 0x01 struct ring_buffer { - atomic_t refcount; + refcount_t refcount; struct rcu_head rcu_head; #ifdef CONFIG_PERF_USE_VMALLOC struct work_struct work; diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index f684d8e..86e1379 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -284,7 +284,7 @@ ring_buffer_init(struct ring_buffer *rb, long watermark, int flags) else rb->overwrite = 1; - atomic_set(&rb->refcount, 1); + refcount_set(&rb->refcount, 1); INIT_LIST_HEAD(&rb->event_list); spin_lock_init(&rb->event_lock); -- 2.7.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-10-20 12:16 UTC|newest] Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-10-20 12:15 [PATCH 00/15] v5 kernel core pieces refcount conversions Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 01/15] sched: convert sighand_struct.count to refcount_t Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:43 ` Thomas Gleixner 2017-10-20 12:43 ` Thomas Gleixner 2017-10-23 10:22 ` Reshetova, Elena 2017-10-23 10:22 ` Reshetova, Elena 2017-10-23 10:26 ` Thomas Gleixner 2017-10-23 10:26 ` Thomas Gleixner 2017-10-23 10:26 ` Thomas Gleixner 2017-10-23 10:45 ` Reshetova, Elena 2017-10-23 10:45 ` Reshetova, Elena 2017-10-20 12:15 ` [PATCH 02/15] sched: convert signal_struct.sigcnt " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 03/15] sched: convert user_struct.__count " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 04/15] sched: convert numa_group.refcount " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 05/15] sched/task_struct: convert task_struct.usage " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 06/15] sched/task_struct: convert task_struct.stack_refcount " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 07/15] perf: convert perf_event_context.refcount " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova [this message] 2017-10-20 12:15 ` [PATCH 08/15] perf/ring_buffer: convert ring_buffer.refcount " Elena Reshetova 2017-10-20 12:15 ` [PATCH 09/15] perf/ring_buffer: convert ring_buffer.aux_refcount " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 10/15] uprobes: convert uprobe.ref " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 11/15] nsproxy: convert nsproxy.count " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 12/15] groups: convert group_info.usage " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 13/15] creds: convert cred.usage " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 14/15] kcov: convert kcov.refcount " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova 2017-10-20 12:15 ` [PATCH 15/15] bdi: convert bdi_writeback_congested.refcnt from atomic_t " Elena Reshetova 2017-10-20 12:15 ` Elena Reshetova -- strict thread matches above, loose matches on Subject: below -- 2017-08-30 12:22 [PATCH 00/15] v5 kernel core pieces refcount conversions Elena Reshetova 2017-08-30 12:22 ` [PATCH 08/15] perf/ring_buffer: convert ring_buffer.refcount to refcount_t Elena Reshetova 2017-08-25 9:41 [PATCH 00/15] v4 kernel core pieces refcount conversions Elena Reshetova 2017-08-25 9:41 ` [PATCH 08/15] perf/ring_buffer: convert ring_buffer.refcount to refcount_t Elena Reshetova 2017-07-18 10:29 [PATCH 00/15] v4 kernel core pieces refcount conversions Elena Reshetova 2017-07-18 10:30 ` [PATCH 08/15] perf/ring_buffer: convert ring_buffer.refcount to refcount_t Elena Reshetova
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