[Libguestfs] [nbdkit PATCH 1/4] server: Check for pthread lock failures

Low-level pthread locks should not fail except in extreme cases of programmer bugs; we're better off calling attention to such bugs rather than just assuming that they work and continuing on with possibly inconsistent state. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- server/connections.c | 20 ++++++++++++-------- server/locks.c | 42 ++++++++++++++++++++++++++---------------- 2 files changed, 38 insertions(+), 24 deletions(-) diff --git a/server/connections.c b/server/connections.c index a30a541..b7d9a6a 100644 --- a/server/connections.c +++ b/server/connections.c @@ -91,11 +91,13 @@ connection_get_status (struct connection *conn) { int r; - if (conn->nworkers) - pthread_mutex_lock (&conn->status_lock); + if (conn->nworkers && + pthread_mutex_lock (&conn->status_lock)) + abort (); r = conn->status; - if (conn->nworkers) - pthread_mutex_unlock (&conn->status_lock); + if (conn->nworkers && + pthread_mutex_unlock (&conn->status_lock)) + abort (); return r; } @@ -105,12 +107,14 @@ connection_get_status (struct connection *conn) int connection_set_status (struct connection *conn, int value) { - if (conn->nworkers) - pthread_mutex_lock (&conn->status_lock); + if (conn->nworkers && + pthread_mutex_lock (&conn->status_lock)) + abort (); if (value < conn->status) conn->status = value; - if (conn->nworkers) - pthread_mutex_unlock (&conn->status_lock); + if (conn->nworkers && + pthread_mutex_unlock (&conn->status_lock)) + abort (); return value; } diff --git a/server/locks.c b/server/locks.c index f4d6497..d70baf2 100644 --- a/server/locks.c +++ b/server/locks.c @@ -55,49 +55,59 @@ lock_init_thread_model (void) void lock_connection (void) { - if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_CONNECTIONS) - pthread_mutex_lock (&connection_lock); + if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_CONNECTIONS && + pthread_mutex_lock (&connection_lock)) + abort (); } void unlock_connection (void) { - if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_CONNECTIONS) - pthread_mutex_unlock (&connection_lock); + if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_CONNECTIONS && + pthread_mutex_unlock (&connection_lock)) + abort (); } void lock_request (struct connection *conn) { - if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS) - pthread_mutex_lock (&all_requests_lock); + if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS && + pthread_mutex_lock (&all_requests_lock)) + abort (); - if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS) - pthread_mutex_lock (&conn->request_lock); + if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS && + pthread_mutex_lock (&conn->request_lock)) + abort (); - pthread_rwlock_rdlock (&unload_prevention_lock); + if (pthread_rwlock_rdlock (&unload_prevention_lock)) + abort (); } void unlock_request (struct connection *conn) { - pthread_rwlock_unlock (&unload_prevention_lock); + if (pthread_rwlock_unlock (&unload_prevention_lock)) + abort (); - if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS) - pthread_mutex_unlock (&conn->request_lock); + if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS && + pthread_mutex_unlock (&conn->request_lock)) + abort (); - if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS) - pthread_mutex_unlock (&all_requests_lock); + if (thread_model <= NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS && + pthread_mutex_unlock (&all_requests_lock)) + abort (); } void lock_unload (void) { - pthread_rwlock_wrlock (&unload_prevention_lock); + if (pthread_rwlock_wrlock (&unload_prevention_lock)) + abort (); } void unlock_unload (void) { - pthread_rwlock_unlock (&unload_prevention_lock); + if (pthread_rwlock_unlock (&unload_prevention_lock)) + abort (); } -- 2.20.1