* [PATCH] plugins/hotblocks: Fix potential deadlock in plugin_exit() function
@ 2023-09-21 6:12 Cong Liu
2023-09-21 7:43 ` Philippe Mathieu-Daudé
0 siblings, 1 reply; 4+ messages in thread
From: Cong Liu @ 2023-09-21 6:12 UTC (permalink / raw)
To: Alex Bennée, Alexandre Iooss, Mahmoud Mandour; +Cc: Cong Liu, qemu-devel
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 <liucong2@kylinos.cn>
---
contrib/plugins/hotblocks.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/contrib/plugins/hotblocks.c b/contrib/plugins/hotblocks.c
index 6b74d25fead6..1f713f1904f3 100644
--- a/contrib/plugins/hotblocks.c
+++ b/contrib/plugins/hotblocks.c
@@ -70,6 +70,8 @@ static void plugin_exit(qemu_plugin_id_t id, void *p)
g_list_free(it);
g_mutex_unlock(&lock);
+ } else {
+ g_mutex_unlock(&lock);
}
qemu_plugin_outs(report->str);
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] plugins/hotblocks: Fix potential deadlock in plugin_exit() function
2023-09-21 6:12 [PATCH] plugins/hotblocks: Fix potential deadlock in plugin_exit() function Cong Liu
@ 2023-09-21 7:43 ` Philippe Mathieu-Daudé
2023-09-21 9:23 ` [PATCH v2] " Cong Liu
0 siblings, 1 reply; 4+ messages in thread
From: Philippe Mathieu-Daudé @ 2023-09-21 7:43 UTC (permalink / raw)
To: Cong Liu, Alex Bennée, Alexandre Iooss, Mahmoud Mandour; +Cc: qemu-devel
Hi Cong,
On 21/9/23 08:12, 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.
You are correct.
> Signed-off-by: Cong Liu <liucong2@kylinos.cn>
> ---
> contrib/plugins/hotblocks.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/contrib/plugins/hotblocks.c b/contrib/plugins/hotblocks.c
> index 6b74d25fead6..1f713f1904f3 100644
> --- a/contrib/plugins/hotblocks.c
> +++ b/contrib/plugins/hotblocks.c
> @@ -70,6 +70,8 @@ static void plugin_exit(qemu_plugin_id_t id, void *p)
>
> g_list_free(it);
> g_mutex_unlock(&lock);
> + } else {
> + g_mutex_unlock(&lock);
> }
The code stays simpler if you simply move the unlock call out
of the if() statement, here.
>
> qemu_plugin_outs(report->str);
Regards,
Phil.
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH v2] plugins/hotblocks: Fix potential deadlock in plugin_exit() function
2023-09-21 7:43 ` Philippe Mathieu-Daudé
@ 2023-09-21 9:23 ` Cong Liu
2023-09-21 10:24 ` Philippe Mathieu-Daudé
0 siblings, 1 reply; 4+ messages in thread
From: Cong Liu @ 2023-09-21 9:23 UTC (permalink / raw)
To: philmd, Alex Bennée, Alexandre Iooss, Mahmoud Mandour
Cc: liucong2, qemu-devel
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 <liucong2@kylinos.cn>
Suggested-by: Philippe Mathieu-Daudé <philmd@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);
}
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2] plugins/hotblocks: Fix potential deadlock in plugin_exit() function
2023-09-21 9:23 ` [PATCH v2] " Cong Liu
@ 2023-09-21 10:24 ` Philippe Mathieu-Daudé
0 siblings, 0 replies; 4+ messages in thread
From: Philippe Mathieu-Daudé @ 2023-09-21 10:24 UTC (permalink / raw)
To: Cong Liu, Alex Bennée, Alexandre Iooss, Mahmoud Mandour; +Cc: qemu-devel
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 <liucong2@kylinos.cn>
> Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Not really suggested, just reviewed ;)
Reviewed-by: Philippe Mathieu-Daudé <philmd@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);
> }
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-09-21 13:33 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2023-09-21 6:12 [PATCH] plugins/hotblocks: Fix potential deadlock in plugin_exit() function Cong Liu
2023-09-21 7:43 ` Philippe Mathieu-Daudé
2023-09-21 9:23 ` [PATCH v2] " Cong Liu
2023-09-21 10:24 ` Philippe Mathieu-Daudé
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