From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Jackson Subject: [PATCH 04/15] libxl: Fix leak of ctx->lock Date: Fri, 24 Feb 2012 18:54:52 +0000 Message-ID: <1330109703-6536-5-git-send-email-ian.jackson@eu.citrix.com> References: <1330109703-6536-1-git-send-email-ian.jackson@eu.citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1330109703-6536-1-git-send-email-ian.jackson@eu.citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xensource.com Cc: Ian Jackson List-Id: xen-devel@lists.xenproject.org A mutex created with pthread_mutex_init, like ctx->lock, may need to be destroyed with pthread_mutex_destroy. Also, previously, if libxl__init_recursive_mutex failed, the nascent ctx would be leaked. Add some comments which will hopefully make these kind of mistakes less likely in future. Signed-off-by: Ian Jackson Acked-by: Ian Campbell --- tools/libxl/libxl.c | 17 +++++++++++++---- 1 files changed, 13 insertions(+), 4 deletions(-) diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c index 7735223..fd890cf 100644 --- a/tools/libxl/libxl.c +++ b/tools/libxl/libxl.c @@ -39,10 +39,7 @@ int libxl_ctx_alloc(libxl_ctx **pctx, int version, memset(ctx, 0, sizeof(libxl_ctx)); ctx->lg = lg; - if (libxl__init_recursive_mutex(ctx, &ctx->lock) < 0) { - LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "Failed to initialize mutex"); - return ERROR_FAIL; - } + /* First initialise pointers (cannot fail) */ LIBXL_TAILQ_INIT(&ctx->occurred); @@ -61,6 +58,16 @@ int libxl_ctx_alloc(libxl_ctx **pctx, int version, LIBXL_TAILQ_INIT(&ctx->death_list); libxl__ev_xswatch_init(&ctx->death_watch); + /* The mutex is special because we can't idempotently destroy it */ + + if (libxl__init_recursive_mutex(ctx, &ctx->lock) < 0) { + LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "Failed to initialize mutex"); + free(ctx); + ctx = 0; + } + + /* Now ctx is safe for ctx_free; failures simply set rc and "goto out" */ + rc = libxl__poller_init(ctx, &ctx->poller_app); if (rc) goto out; @@ -150,6 +157,8 @@ int libxl_ctx_free(libxl_ctx *ctx) discard_events(&ctx->occurred); + pthread_mutex_destroy(&ctx->lock); + GC_FREE; free(ctx); return 0; -- 1.7.2.5