* [PATCH] mshv: Fix use-after-free in mshv_map_user_memory error path
@ 2026-03-12 16:02 Stanislav Kinsburskii
2026-03-13 21:12 ` Wei Liu
0 siblings, 1 reply; 2+ messages in thread
From: Stanislav Kinsburskii @ 2026-03-12 16:02 UTC (permalink / raw)
To: kys, haiyangz, wei.liu, decui, longli; +Cc: linux-hyperv, linux-kernel
In the error path of mshv_map_user_memory(), calling vfree() directly on
the region leaves the MMU notifier registered. When userspace later unmaps
the memory, the notifier fires and accesses the freed region, causing a
use-after-free and potential kernel panic.
Replace vfree() with mshv_partition_put() to properly unregister
the MMU notifier before freeing the region.
Fixes: b9a66cd5ccbb9 ("mshv: Add support for movable memory regions")
Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
---
drivers/hv/mshv_root_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
index d753f41d3b57..796f3ca8308f 100644
--- a/drivers/hv/mshv_root_main.c
+++ b/drivers/hv/mshv_root_main.c
@@ -1388,7 +1388,7 @@ mshv_map_user_memory(struct mshv_partition *partition,
return 0;
errout:
- vfree(region);
+ mshv_region_put(region);
return ret;
}
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] mshv: Fix use-after-free in mshv_map_user_memory error path
2026-03-12 16:02 [PATCH] mshv: Fix use-after-free in mshv_map_user_memory error path Stanislav Kinsburskii
@ 2026-03-13 21:12 ` Wei Liu
0 siblings, 0 replies; 2+ messages in thread
From: Wei Liu @ 2026-03-13 21:12 UTC (permalink / raw)
To: Stanislav Kinsburskii
Cc: kys, haiyangz, wei.liu, decui, longli, linux-hyperv, linux-kernel
On Thu, Mar 12, 2026 at 04:02:53PM +0000, Stanislav Kinsburskii wrote:
> In the error path of mshv_map_user_memory(), calling vfree() directly on
> the region leaves the MMU notifier registered. When userspace later unmaps
> the memory, the notifier fires and accesses the freed region, causing a
> use-after-free and potential kernel panic.
>
> Replace vfree() with mshv_partition_put() to properly unregister
> the MMU notifier before freeing the region.
>
> Fixes: b9a66cd5ccbb9 ("mshv: Add support for movable memory regions")
> Signed-off-by: Stanislav Kinsburskii <skinsburskii@linux.microsoft.com>
Applied to hyperv-fixes. Thanks.
^ permalink raw reply [flat|nested] 2+ messages in thread
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