From c33ceb0250b3a51f7f53993e51e2032ddbe88fe2 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Fri, 1 Mar 2013 11:26:12 -0500 Subject: [PATCH] Fix: set wait/wake fd to -1 before close Else triggers double-close race. Signed-off-by: Mathieu Desnoyers --- libringbuffer/shm.h | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/libringbuffer/shm.h b/libringbuffer/shm.h index 3d22a313..a1ddc4cd 100644 --- a/libringbuffer/shm.h +++ b/libringbuffer/shm.h @@ -141,6 +141,7 @@ int shm_close_wait_fd(struct lttng_ust_shm_handle *handle, { struct shm_object_table *table = handle->table; struct shm_object *obj; + int wait_fd; size_t index; int ret; @@ -148,14 +149,15 @@ int shm_close_wait_fd(struct lttng_ust_shm_handle *handle, if (caa_unlikely(index >= table->allocated_len)) return -EPERM; obj = &table->objects[index]; - if (obj->wait_fd[0] < 0) + wait_fd = obj->wait_fd[0]; + if (wait_fd < 0) return -ENOENT; - ret = close(obj->wait_fd[0]); + obj->wait_fd[0] = -1; + ret = close(wait_fd); if (ret) { ret = -errno; return ret; } - obj->wait_fd[0] = -1; return 0; } @@ -165,6 +167,7 @@ int shm_close_wakeup_fd(struct lttng_ust_shm_handle *handle, { struct shm_object_table *table = handle->table; struct shm_object *obj; + int wakeup_fd; size_t index; int ret; @@ -172,14 +175,15 @@ int shm_close_wakeup_fd(struct lttng_ust_shm_handle *handle, if (caa_unlikely(index >= table->allocated_len)) return -EPERM; obj = &table->objects[index]; - if (obj->wait_fd[1] < 0) + wakeup_fd = obj->wait_fd[1]; + if (wakeup_fd < 0) return -ENOENT; - ret = close(obj->wait_fd[1]); + obj->wait_fd[1] = -1; + ret = close(wakeup_fd); if (ret) { ret = -errno; return ret; } - obj->wait_fd[1] = -1; return 0; } -- 2.34.1