Re: [PATCH net-next 03/13] virtio_ring: packed: harden dma unmap for indirect
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2024-09-11 11:28:45
Also in:
bpf, virtualization
As gcc luckily noted: On Tue, Aug 20, 2024 at 03:33:20PM +0800, Xuan Zhuo wrote:
quoted hunk ↗ jump to hunk
@@ -1617,23 +1617,24 @@ static void detach_buf_packed(struct vring_virtqueue *vq, } if (vq->indirect) { + struct vring_desc_extra *extra; u32 len; /* Free the indirect table, if any, now that it's unmapped. */ - desc = state->indir_desc; - if (!desc)
desc is no longer initialized here
+ extra = state->indir;
+ if (!extra)
return;
if (vring_need_unmap_buffer(vq)) {
len = vq->packed.desc_extra[id].len;
for (i = 0; i < len / sizeof(struct vring_packed_desc);
i++)
- vring_unmap_desc_packed(vq, &desc[i]);
+ vring_unmap_extra_packed(vq, &extra[i]);
}
kfree(desc);but freed here
- state->indir_desc = NULL;
+ state->indir = NULL;
} else if (ctx) {
- *ctx = state->indir_desc;
+ *ctx = state->indir;
}
}It seems unlikely this was always 0 on all paths with even a small amount of stress, so now I question how this was tested. Besides, do not ignore compiler warnings, and do not tweak code to just make compiler shut up - they are your friend.
-- 2.32.0.3.g01195cf9f