when the thread pool is dynamically expanded, threads should
not be created from the existing workers; they should be created
from the newly expanded workers

Signed-off-by: Wei Gong <gongwei833x@gmail.com>
---
 src/util/virthreadpool.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/src/util/virthreadpool.c b/src/util/virthreadpool.c
index d45fa92061..de8113df81 100644
--- a/src/util/virthreadpool.c
+++ b/src/util/virthreadpool.c
@@ -184,7 +184,8 @@ virThreadPoolExpand(virThreadPool *pool, size_t gain, bool priority)
     size_t i = 0;
     struct virThreadPoolWorkerData *data = NULL;
 
-    VIR_EXPAND_N(*workers, *curWorkers, gain);
+    VIR_REALLOC_N(*workers, *curWorkers + gain);
+    memset(&(*workers)[*curWorkers], 0, sizeof(virThread) * gain);
 
     for (i = 0; i < gain; i++) {
         g_autofree char *name = NULL;
@@ -199,7 +200,7 @@ virThreadPoolExpand(virThreadPool *pool, size_t gain, bool priority)
         else
             name = g_strdup(pool->jobName);
 
-        if (virThreadCreateFull(&(*workers)[i],
+        if (virThreadCreateFull(&(*workers)[*curWorkers],
                                 false,
                                 virThreadPoolWorker,
                                 name,
@@ -207,15 +208,13 @@ virThreadPoolExpand(virThreadPool *pool, size_t gain, bool priority)
                                 data) < 0) {
             VIR_FREE(data);
             virReportSystemError(errno, "%s", _("Failed to create thread"));
-            goto error;
+            return -1;
         }
+
+        (*curWorkers)++;
     }
 
     return 0;
-
- error:
-    *curWorkers -= gain - i;
-    return -1;
 }
 
 virThreadPool *
-- 
2.32.1 (Apple Git-133)
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On 3/18/24 14:31, Wei Gong wrote:
> when the thread pool is dynamically expanded, threads should
> not be created from the existing workers; they should be created
> from the newly expanded workers
> 
> Signed-off-by: Wei Gong <gongwei833x@gmail.com>
> ---
>  src/util/virthreadpool.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/src/util/virthreadpool.c b/src/util/virthreadpool.c
> index d45fa92061..de8113df81 100644
> --- a/src/util/virthreadpool.c
> +++ b/src/util/virthreadpool.c
> @@ -184,7 +184,8 @@ virThreadPoolExpand(virThreadPool *pool, size_t gain, bool priority)
>      size_t i = 0;
>      struct virThreadPoolWorkerData *data = NULL;
>  
> -    VIR_EXPAND_N(*workers, *curWorkers, gain);
> +    VIR_REALLOC_N(*workers, *curWorkers + gain);

> +    memset(&(*workers)[*curWorkers], 0, sizeof(virThread) * gain);

I don't think it's safe to do this ^^^.

Firstly, pthread_t is an opaque type. We don't know if all zeroes are
valid value (that's why there are functions like pthread_equal()) or if
it's a valid init value.
Secondly, since *curWorkers is incremented at only after successful
thread creation, we can no longer get it to point to an uninitialized
array item.

I'll drop this line before pushing.

>  
>      for (i = 0; i < gain; i++) {
>          g_autofree char *name = NULL;
> @@ -199,7 +200,7 @@ virThreadPoolExpand(virThreadPool *pool, size_t gain, bool priority)
>          else
>              name = g_strdup(pool->jobName);
>  
> -        if (virThreadCreateFull(&(*workers)[i],
> +        if (virThreadCreateFull(&(*workers)[*curWorkers],
>                                  false,
>                                  virThreadPoolWorker,
>                                  name,
> @@ -207,15 +208,13 @@ virThreadPoolExpand(virThreadPool *pool, size_t gain, bool priority)
>                                  data) < 0) {
>              VIR_FREE(data);
>              virReportSystemError(errno, "%s", _("Failed to create thread"));
> -            goto error;
> +            return -1;
>          }
> +
> +        (*curWorkers)++;
>      }
>  
>      return 0;
> -
> - error:
> -    *curWorkers -= gain - i;
> -    return -1;
>  }
>  
>  virThreadPool *

Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

and merged. Congratulations on your first libvirt contribution!

Michal
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