zink: fix heap-use-after-free on batch_state with sub-allocated pipe_resources

zink_bo_create can run into a heap-use-after-free when the bo is still
referencing an batch_state from an older destroyed context. In order to
fix this, every context gives back their batch_states to the zink, where
they can be reused from for new contexts.

Cc: mesa-stable
Suggested-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26889>

src/gallium/drivers/zink/zink_batch.c

@@ -446,6 +446,18 @@ get_batch_state(struct zink_context *ctx, struct zink_batch *batch)
       if (bs == ctx->last_free_batch_state)
          ctx->last_free_batch_state = NULL;
    }
+   /* try from the ones that are given back to the screen next */
+   if (!bs) {
+      simple_mtx_lock(&screen->free_batch_states_lock);
+      if (screen->free_batch_states) {
+         bs = screen->free_batch_states;
+         bs->ctx = ctx;
+         screen->free_batch_states = bs->next;
+         if (bs == screen->last_free_batch_state)
+            screen->last_free_batch_state = NULL;
+      }
+      simple_mtx_unlock(&screen->free_batch_states_lock);
+   }
    if (!bs && ctx->batch_states) {
       /* states are stored sequentially, so if the first one doesn't work, none of them will */
       if (zink_screen_check_last_finished(screen, ctx->batch_states->fence.batch_id) ||

src/gallium/drivers/zink/zink_context.c

@@ -162,16 +162,41 @@ zink_context_destroy(struct pipe_context *pctx)
    while (bs) {
       struct zink_batch_state *bs_next = bs->next;
       zink_clear_batch_state(ctx, bs);
-      zink_batch_state_destroy(screen, bs);
+      /* restore link as we insert them into the screens free_batch_states
+       * list below
+       */
+      bs->next = bs_next;
       bs = bs_next;
    }
    bs = ctx->free_batch_states;
    while (bs) {
       struct zink_batch_state *bs_next = bs->next;
       zink_clear_batch_state(ctx, bs);
-      zink_batch_state_destroy(screen, bs);
+      /* restore link as we insert them into the screens free_batch_states
+       * list below
+       */
+      bs->next = bs_next;
       bs = bs_next;
    }
+   simple_mtx_lock(&screen->free_batch_states_lock);
+   if (ctx->batch_states) {
+      if (screen->free_batch_states)
+         screen->last_free_batch_state->next = ctx->batch_states;
+      else {
+         screen->free_batch_states = ctx->batch_states;
+         screen->last_free_batch_state = screen->free_batch_states;
+      }
+      while (screen->last_free_batch_state->next)
+         screen->last_free_batch_state = screen->last_free_batch_state->next;
+   }
+   if (ctx->free_batch_states) {
+      if (screen->free_batch_states)
+         screen->last_free_batch_state->next = ctx->free_batch_states;
+      else
+         screen->free_batch_states = ctx->free_batch_states;
+      screen->last_free_batch_state = ctx->last_free_batch_state;
+   }
+   simple_mtx_unlock(&screen->free_batch_states_lock);
    if (ctx->batch.state) {
       zink_clear_batch_state(ctx, ctx->batch.state);
       zink_batch_state_destroy(screen, ctx->batch.state);

src/gallium/drivers/zink/zink_screen.c

@@ -1463,6 +1463,12 @@ static void
 zink_destroy_screen(struct pipe_screen *pscreen)
 {
    struct zink_screen *screen = zink_screen(pscreen);
+   struct zink_batch_state *bs = screen->free_batch_states;
+   while (bs) {
+      struct zink_batch_state *bs_next = bs->next;
+      zink_batch_state_destroy(screen, bs);
+      bs = bs_next;
+   }
 
 #ifdef HAVE_RENDERDOC_APP_H
    if (screen->renderdoc_capture_all && p_atomic_dec_zero(&num_screens))
@@ -3498,6 +3504,7 @@ zink_internal_create_screen(const struct pipe_screen_config *config, int64_t dev
       screen->base_descriptor_size = MAX4(screen->db_size[0], screen->db_size[1], screen->db_size[2], screen->db_size[3]);
    }
 
+   simple_mtx_init(&screen->free_batch_states_lock, mtx_plain);
    simple_mtx_init(&screen->dt_lock, mtx_plain);
 
    util_idalloc_mt_init_tc(&screen->buffer_ids);

src/gallium/drivers/zink/zink_types.h

@@ -1416,6 +1416,10 @@ struct zink_screen {
    simple_mtx_t copy_context_lock;
    struct zink_context *copy_context;
 
+   struct zink_batch_state *free_batch_states; //unused batch states
+   struct zink_batch_state *last_free_batch_state; //for appending
+   simple_mtx_t free_batch_states_lock;
+
    simple_mtx_t semaphores_lock;
    struct util_dynarray semaphores;
    struct util_dynarray fd_semaphores;