[PATCH] vduse: Fix a possible warning in vduse_create_dev()

From: Harshit Mogalapalli
Date: Fri Nov 25 2022 - 23:00:41 EST


As 'dev->vq_num' is user-controlled data, if user tries to allocate
memory larger than(>=) MAX_ORDER, then kcalloc() will fail, it
creates a stack trace and messes up dmesg with a warning.

Call trace:
-> vduse_ioctl
--> vduse_create_dev
'config->vq_num' is user data as it comes from ioctl, which is
assigned to 'dev->vq_num'.

Add __GFP_NOWARN in order to avoid too large allocation warning.
This is detected by static analysis using smatch.

Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
---
drivers/vdpa/vdpa_user/vduse_dev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 35dceee3ed56..5e9546b16165 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -1512,7 +1512,8 @@ static int vduse_create_dev(struct vduse_dev_config *config,
dev->config_size = config->config_size;
dev->vq_align = config->vq_align;
dev->vq_num = config->vq_num;
- dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs), GFP_KERNEL);
+ dev->vqs = kcalloc(dev->vq_num, sizeof(*dev->vqs),
+ GFP_KERNEL | __GFP_NOWARN);
if (!dev->vqs)
goto err_vqs;

--
2.38.1