From 990e331218dba6b671854cec24f639ff45763d7d Mon Sep 17 00:00:00 2001 From: Keir Fraser Date: Wed, 12 May 2010 08:49:13 +0100 Subject: [PATCH] xs: avoid pthread_join deadlock in xs_daemon_close Doing a pthread_cancel and join on the reader thread while holding all the request/reply/watch mutexes can deadlock if the thread needs to take any of those mutexes to exit. Kill off the reader thread before taking any mutexes (which should be redundant if we're single-threaded at that point). Signed-off-by: Jeremy Fitzhardinge --- tools/xenstore/xs.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/tools/xenstore/xs.c b/tools/xenstore/xs.c index 6a87ccf708..53e3d44345 100644 --- a/tools/xenstore/xs.c +++ b/tools/xenstore/xs.c @@ -260,10 +260,6 @@ void xs_daemon_destroy_postfork(struct xs_handle *h) void xs_daemon_close(struct xs_handle *h) { - mutex_lock(&h->request_mutex); - mutex_lock(&h->reply_mutex); - mutex_lock(&h->watch_mutex); - #ifdef USE_PTHREAD if (h->read_thr_exists) { pthread_cancel(h->read_thr); @@ -271,6 +267,10 @@ void xs_daemon_close(struct xs_handle *h) } #endif + mutex_lock(&h->request_mutex); + mutex_lock(&h->reply_mutex); + mutex_lock(&h->watch_mutex); + close_free_msgs(h); mutex_unlock(&h->request_mutex); -- 2.39.5