Re: [PATCH v2] plugins/hotblocks: Fix potential deadlock in plugin_exit() function

[Philippe Mathieu-Daudé]

On 21/9/23 11:23, Cong Liu wrote:

This patch fixes a potential deadlock in the plugin_exit() function of QEMU.
The original code does not release the lock mutex if it is NULL. This patch
adds a check for it being NULL and releases the mutex in that case.

Signed-off-by: Cong Liu <liuco...@kylinos.cn>
Suggested-by: Philippe Mathieu-Daudé <phi...@linaro.org>

Not really suggested, just reviewed ;)

Reviewed-by: Philippe Mathieu-Daudé <phi...@linaro.org>

---
  contrib/plugins/hotblocks.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/contrib/plugins/hotblocks.c b/contrib/plugins/hotblocks.c
index 6b74d25fead6..b99b93ad8dc7 100644
--- a/contrib/plugins/hotblocks.c
+++ b/contrib/plugins/hotblocks.c
@@ -69,9 +69,9 @@ static void plugin_exit(qemu_plugin_id_t id, void *p)
          }

g_list_free(it);

-        g_mutex_unlock(&lock);
      }

+ g_mutex_unlock(&lock);

      qemu_plugin_outs(report->str);
  }