fix(quest): ignore a finished wait when its KGSL context was recreated

tools/quest/kgsl_compat.c

@@ -31,11 +31,12 @@ static void report(const char *operation, int error) {
 }
 
 struct tracked_context {
-    unsigned int context, queued, retired;
+    unsigned int context, queued, retired, generation;
 };
 
 static struct tracked_context *tracked;
 static unsigned int tracked_count, tracked_capacity;
+static unsigned int next_generation;
 static char tracked_lock;
 
 static void tracked_acquire(void) {
@@ -65,6 +66,7 @@ static int tracked_find(unsigned int context, int create) {
     }
     tracked[free_slot].context = context;
     tracked[free_slot].queued = tracked[free_slot].retired = 0;
+    tracked[free_slot].generation = ++next_generation;
     return free_slot;
 }
 
@@ -92,6 +94,7 @@ static int read_timestamp(quest_ioctl_fn real, int fd, struct kgsl_cmdstream_rea
     int slot = tracked_find(query->context_id, 0);
     unsigned int queued = slot < 0 ? 0 : tracked[slot].queued;
     unsigned int retired = slot < 0 ? 0 : tracked[slot].retired;
+    unsigned int generation = slot < 0 ? 0 : tracked[slot].generation;
     tracked_release();
     if (slot < 0 || (query->type != KGSL_TIMESTAMP_RETIRED && query->type != KGSL_TIMESTAMP_QUEUED)) {
         errno = EACCES;
@@ -105,7 +108,8 @@ static int read_timestamp(quest_ioctl_fn real, int fd, struct kgsl_cmdstream_rea
             retired = queued;
             tracked_acquire();
             slot = tracked_find(query->context_id, 0);
-            if (slot >= 0 && (int)(retired - tracked[slot].retired) > 0) tracked[slot].retired = retired;
+            if (slot >= 0 && tracked[slot].generation == generation &&
+                (int)(retired - tracked[slot].retired) > 0) tracked[slot].retired = retired;
             tracked_release();
         } else if (errno != ETIMEDOUT) {
             return -1;

tools/quest/test_kgsl_compat.c

@@ -45,6 +45,7 @@ static struct kgsl_gpumem_alloc_id reset(void) {
 }
 static int read_error, wait_error, waits;
 static unsigned int waited_for;
+static void (*during_wait)(void);
 static int timestamp_mock(int fd, unsigned long request, void *arg) {
     assert(fd == 42);
     if (request == IOCTL_KGSL_GPU_COMMAND || request == IOCTL_KGSL_DRAWCTXT_DESTROY) return 0;
@@ -57,6 +58,7 @@ static int timestamp_mock(int fd, unsigned long request, void *arg) {
         assert(w->timeout == 0);
         waits++;
         waited_for = w->timestamp;
+        if (during_wait) during_wait();
         if (wait_error) { errno = wait_error; return -1; }
         return 0;
     }
@@ -73,6 +75,13 @@ static int read_ts(unsigned int context, unsigned int type, unsigned int *timest
     *timestamp = q.timestamp;
     return rc;
 }
+static void submit(unsigned int context, unsigned int timestamp);
+static void recreate_context(void) {
+    struct kgsl_drawctxt_destroy gone = {.drawctxt_id = 8};
+    during_wait = NULL;
+    assert(quest_kgsl_ioctl(timestamp_mock, 42, IOCTL_KGSL_DRAWCTXT_DESTROY, &gone) == 0);
+    submit(8, 20);
+}
 static void timestamp_scenarios(void) {
     unsigned int ts;
     read_error = EACCES;
@@ -99,6 +108,13 @@ static void timestamp_scenarios(void) {
     assert(read_ts(5, KGSL_TIMESTAMP_QUEUED, &ts) == -1 && errno == EACCES);
     for (unsigned int c = 100; c < 100 + 129; c++) submit(c, c);
     for (unsigned int c = 100; c < 100 + 129; c++) assert(read_ts(c, KGSL_TIMESTAMP_QUEUED, &ts) == 0 && ts == c);
+    submit(8, 5);
+    during_wait = recreate_context;
+    assert(read_ts(8, KGSL_TIMESTAMP_RETIRED, &ts) == 0 && ts == 5);
+    wait_error = ETIMEDOUT;
+    assert(read_ts(8, KGSL_TIMESTAMP_RETIRED, &ts) == 0 && ts == 0 && waited_for == 20);
+    wait_error = 0;
+    assert(read_ts(8, KGSL_TIMESTAMP_RETIRED, &ts) == 0 && ts == 20);
     read_error = EIO;
     submit(6, 3);
     assert(read_ts(6, KGSL_TIMESTAMP_QUEUED, &ts) == -1 && errno == EIO);