[PATCH] blkdebug: ignore invalid rules in non-coroutine context

[Paolo Bonzini <pbonzini@redhat.com>]

blkdebug events can be called from either non-coroutine or coroutine
contexts.  However, suspend actions only make sense from within
a coroutine.  Currently, using those action would lead to an abort() in
qemu_coroutine_yield() ("Co-routine is yielding to no one").  Catch them
and print an error instead.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 block.c                          |  2 +-
 block/blkdebug.c                 | 10 ++++++++--
 include/block/block-io.h         |  2 +-
 include/block/block_int-common.h |  3 ++-
 4 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/block.c b/block.c
index 3f2bd128570e..49c66475c73e 100644
--- a/block.c
+++ b/block.c
@@ -6334,7 +6334,7 @@ BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs)
     return drv->bdrv_get_specific_stats(bs);
 }
 
-void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
+void coroutine_mixed_fn bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
 {
     IO_CODE();
     if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
diff --git a/block/blkdebug.c b/block/blkdebug.c
index 4265ca125e25..ce297961b7db 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -31,6 +31,7 @@
 #include "block/qdict.h"
 #include "qemu/module.h"
 #include "qemu/option.h"
+#include "qemu/error-report.h"
 #include "qapi/qapi-visit-block-core.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qlist.h"
@@ -837,7 +838,7 @@ static void process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
     }
 }
 
-static void blkdebug_debug_event(BlockDriverState *bs, BlkdebugEvent event)
+static void coroutine_mixed_fn blkdebug_debug_event(BlockDriverState *bs, BlkdebugEvent event)
 {
     BDRVBlkdebugState *s = bs->opaque;
     struct BlkdebugRule *rule, *next;
@@ -855,7 +856,12 @@ static void blkdebug_debug_event(BlockDriverState *bs, BlkdebugEvent event)
     }
 
     while (actions_count[ACTION_SUSPEND] > 0) {
-        qemu_coroutine_yield();
+        if (qemu_in_coroutine()) {
+            qemu_coroutine_yield();
+        } else {
+            error_report("Non-coroutine event %s cannot suspend\n",
+                         BlkdebugEvent_lookup.array[event]);
+        }
         actions_count[ACTION_SUSPEND]--;
     }
 }
diff --git a/include/block/block-io.h b/include/block/block-io.h
index 1fa717a545a0..0e7032a23936 100644
--- a/include/block/block-io.h
+++ b/include/block/block-io.h
@@ -175,7 +175,7 @@ void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
 void bdrv_enable_copy_on_read(BlockDriverState *bs);
 void bdrv_disable_copy_on_read(BlockDriverState *bs);
 
-void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
+void coroutine_mixed_fn bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
 
 #define BLKDBG_EVENT(child, evt) \
     do { \
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index c34c525fa6ba..1d4fd5094a5b 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -726,7 +726,8 @@ struct BlockDriver {
     int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_check)(
         BlockDriverState *bs, BdrvCheckResult *result, BdrvCheckMode fix);
 
-    void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event);
+    void coroutine_mixed_fn (*bdrv_debug_event)(BlockDriverState *bs,
+                                                BlkdebugEvent event);
 
     /* io queue for linux-aio */
     void (*bdrv_io_plug)(BlockDriverState *bs);
-- 
2.38.1