This is a note to let you know that I've just added the patch titled
vhost-vdpa: fix an iotlb memory leak
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vhost-vdpa-fix-an-iotlb-memory-leak.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6db7d7a9c1377e3b9d2cdf358d139717f9d744cb
Author: Stefano Garzarella <sgarzare@xxxxxxxxxx>
Date: Wed Nov 9 16:42:13 2022 +0100
vhost-vdpa: fix an iotlb memory leak
[ Upstream commit c070c1912a83432530cbb4271d5b9b11fa36b67a ]
Before commit 3d5698793897 ("vhost-vdpa: introduce asid based IOTLB")
we called vhost_vdpa_iotlb_unmap(v, iotlb, 0ULL, 0ULL - 1) during
release to free all the resources allocated when processing user IOTLB
messages through vhost_vdpa_process_iotlb_update().
That commit changed the handling of IOTLB a bit, and we accidentally
removed some code called during the release.
We partially fixed this with commit 037d4305569a ("vhost-vdpa: call
vhost_vdpa_cleanup during the release") but a potential memory leak is
still there as showed by kmemleak if the application does not send
VHOST_IOTLB_INVALIDATE or crashes:
unreferenced object 0xffff888007fbaa30 (size 16):
comm "blkio-bench", pid 914, jiffies 4294993521 (age 885.500s)
hex dump (first 16 bytes):
40 73 41 07 80 88 ff ff 00 00 00 00 00 00 00 00 @sA.............
backtrace:
[<0000000087736d2a>] kmem_cache_alloc_trace+0x142/0x1c0
[<0000000060740f50>] vhost_vdpa_process_iotlb_msg+0x68c/0x901 [vhost_vdpa]
[<0000000083e8e205>] vhost_chr_write_iter+0xc0/0x4a0 [vhost]
[<000000008f2f414a>] vhost_vdpa_chr_write_iter+0x18/0x20 [vhost_vdpa]
[<00000000de1cd4a0>] vfs_write+0x216/0x4b0
[<00000000a2850200>] ksys_write+0x71/0xf0
[<00000000de8e720b>] __x64_sys_write+0x19/0x20
[<0000000018b12cbb>] do_syscall_64+0x3f/0x90
[<00000000986ec465>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
Let's fix this calling vhost_vdpa_iotlb_unmap() on the whole range in
vhost_vdpa_remove_as(). We move that call before vhost_dev_cleanup()
since we need a valid v->vdev.mm in vhost_vdpa_pa_unmap().
vhost_iotlb_reset() call can be removed, since vhost_vdpa_iotlb_unmap()
on the whole range removes all the entries.
The kmemleak log reported was observed with a vDPA device that has `use_va`
set to true (e.g. VDUSE). This patch has been tested with both types of
devices.
Fixes: 037d4305569a ("vhost-vdpa: call vhost_vdpa_cleanup during the release")
Fixes: 3d5698793897 ("vhost-vdpa: introduce asid based IOTLB")
Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
Message-Id: <20221109154213.146789-1-sgarzare@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 166044642fd5..b08e07fc7d1f 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -65,6 +65,10 @@ static DEFINE_IDA(vhost_vdpa_ida);
static dev_t vhost_vdpa_major;
+static void vhost_vdpa_iotlb_unmap(struct vhost_vdpa *v,
+ struct vhost_iotlb *iotlb,
+ u64 start, u64 last);
+
static inline u32 iotlb_to_asid(struct vhost_iotlb *iotlb)
{
struct vhost_vdpa_as *as = container_of(iotlb, struct
@@ -135,7 +139,7 @@ static int vhost_vdpa_remove_as(struct vhost_vdpa *v, u32 asid)
return -EINVAL;
hlist_del(&as->hash_link);
- vhost_iotlb_reset(&as->iotlb);
+ vhost_vdpa_iotlb_unmap(v, &as->iotlb, 0ULL, 0ULL - 1);
kfree(as);
return 0;
@@ -1162,14 +1166,14 @@ static void vhost_vdpa_cleanup(struct vhost_vdpa *v)
struct vhost_vdpa_as *as;
u32 asid;
- vhost_dev_cleanup(&v->vdev);
- kfree(v->vdev.vqs);
-
for (asid = 0; asid < v->vdpa->nas; asid++) {
as = asid_to_as(v, asid);
if (as)
vhost_vdpa_remove_as(v, asid);
}
+
+ vhost_dev_cleanup(&v->vdev);
+ kfree(v->vdev.vqs);
}
static int vhost_vdpa_open(struct inode *inode, struct file *filep)
