[PATCH 0/4] MR9026: server: Use the access time and signal state to detect hung queue.

[PATCH 1/4] server: Update queue access time in set_queue_mask request.

[Rémi Bernon]

From: Rémi Bernon

This is called before waiting on the queue and makes the access time
reliable to detect hung queues.
---
 server/queue.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/server/queue.c b/server/queue.c
index 3f06c15d006..f139793e400 100644
--- a/server/queue.c
+++ b/server/queue.c
@@ -3161,6 +3161,7 @@ DECL_HANDLER(set_queue_mask)

SHARED_WRITE_BEGIN( queue_shm, queue_shm_t )
     {
+        shared->access_time  = monotonic_time;
         shared->wake_mask    = req->wake_mask;
         shared->changed_mask = req->changed_mask;
         reply->wake_bits     = shared->wake_bits;

[PATCH 2/4] win32u: Check the queue access time before skipping set_queue_mask.

[Rémi Bernon]

From: Rémi Bernon

---
 dlls/win32u/message.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/dlls/win32u/message.c b/dlls/win32u/message.c
index d3ef83785bb..df64e059177 100644
--- a/dlls/win32u/message.c
+++ b/dlls/win32u/message.c
@@ -3229,7 +3229,10 @@ static BOOL check_queue_masks( UINT wake_mask, UINT changed_mask )
     UINT status;

while ((status = get_shared_queue( &lock, &queue_shm )) == STATUS_PENDING)
-        skip = queue_shm->wake_mask == wake_mask && queue_shm->changed_mask == changed_mask;
+    {
+        if (queue_shm->wake_mask != wake_mask || queue_shm->changed_mask != changed_mask) skip = FALSE;
+        else skip = get_tick_count() - (UINT64)queue_shm->access_time / 10000 < 3000; /* avoid hung queue */
+    }

if (status) return FALSE;
     return skip;

[PATCH 3/4] server: Use the access time and signal state to detect hung queue.

[Rémi Bernon]

From: Rémi Bernon

---
 server/queue.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/server/queue.c b/server/queue.c
index f139793e400..a1d2595e856 100644
--- a/server/queue.c
+++ b/server/queue.c
@@ -1283,9 +1283,8 @@ static void cleanup_results( struct msg_queue *queue )
 /* check if the thread owning the queue is hung (not checking for messages) */
 static int is_queue_hung( struct msg_queue *queue )
 {
-    if (monotonic_time - queue->shared->access_time <= 5 * TICKS_PER_SEC)
-        return 0;  /* less than 5 seconds since last get message -> not hung */
-    return !queue->waiting;
+    /* queue is hung if it's signaled and thread didn't access it for more than 5 seconds */
+    return queue->signaled && monotonic_time - queue->shared->access_time > 5 * TICKS_PER_SEC;
 }

static int msg_queue_select( struct msg_queue *queue, int events )

[PATCH 4/4] server: Remove the now unnecessary queue waiting flag.

[Rémi Bernon]

From: Rémi Bernon

---
 server/queue.c | 27 ++++++---------------------
 1 file changed, 6 insertions(+), 21 deletions(-)

diff --git a/server/queue.c b/server/queue.c
index a1d2595e856..268c921a914 100644
--- a/server/queue.c
+++ b/server/queue.c
@@ -134,7 +134,6 @@ struct msg_queue
     struct thread_input   *input;           /* thread input descriptor */
     struct hook_table     *hooks;           /* hook table */
     int                    keystate_lock;   /* owns an input keystate lock */
-    int                    waiting;         /* is thread waiting on queue */
     queue_shm_t           *shared;          /* queue in session shared memory */
 };

@@ -319,7 +318,6 @@ static struct msg_queue *create_msg_queue( struct thread *thread, struct thread_
         queue->input           = (struct thread_input *)grab_object( input );
         queue->hooks           = NULL;
         queue->keystate_lock   = 0;
-        queue->waiting         = 0;
         list_init( &queue->send_result );
         list_init( &queue->callback_result );
         list_init( &queue->pending_timers );
@@ -1287,23 +1285,6 @@ static int is_queue_hung( struct msg_queue *queue )
     return queue->signaled && monotonic_time - queue->shared->access_time > 5 * TICKS_PER_SEC;
 }

-static int msg_queue_select( struct msg_queue *queue, int events )
-{
-    if (queue->waiting == !!events)
-    {
-        set_error( STATUS_ACCESS_DENIED );
-        return 0;
-    }
-    queue->waiting = !!events;
-
-    if (queue->fd)
-    {
-        if (events && check_fd_events( queue->fd, POLLIN )) signal_queue_sync( queue );
-        else set_fd_events( queue->fd, events );
-    }
-    return 1;
-}
-
 static int msg_queue_add_queue( struct object *obj, struct wait_queue_entry *entry )
 {
     struct msg_queue *queue = (struct msg_queue *)obj;
@@ -1315,7 +1296,11 @@ static int msg_queue_add_queue( struct object *obj, struct wait_queue_entry *ent
         return 0;
     }

-    if (!msg_queue_select( queue, POLLIN )) return 0;
+    if (queue->fd)
+    {
+        if (check_fd_events( queue->fd, POLLIN )) signal_queue_sync( queue );
+        else set_fd_events( queue->fd, POLLIN );
+    }
     add_queue( obj, entry );
     return 1;
 }
@@ -1325,7 +1310,7 @@ static void msg_queue_remove_queue(struct object *obj, struct wait_queue_entry *
     struct msg_queue *queue = (struct msg_queue *)obj;

remove_queue( obj, entry );
-    msg_queue_select( queue, 0 );
+    if (queue->fd) set_fd_events( queue->fd, 0 );
 }

static void msg_queue_dump( struct object *obj, int verbose )