This is a note to let you know that I've just added the patch titled vhost-vdpa: set v->config_ctx to NULL if eventfd_ctx_fdget() fails to the 5.11-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-set-v-config_ctx-to-null-if-eventfd_ctx_fdget-fails.patch and it can be found in the queue-5.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 0bde59c1723a29e294765c96dbe5c7fb639c2f96 Mon Sep 17 00:00:00 2001 From: Stefano Garzarella <sgarzare@xxxxxxxxxx> Date: Thu, 11 Mar 2021 14:52:57 +0100 Subject: vhost-vdpa: set v->config_ctx to NULL if eventfd_ctx_fdget() fails From: Stefano Garzarella <sgarzare@xxxxxxxxxx> commit 0bde59c1723a29e294765c96dbe5c7fb639c2f96 upstream. In vhost_vdpa_set_config_call() if eventfd_ctx_fdget() fails the 'v->config_ctx' contains an error instead of a valid pointer. Since we consider 'v->config_ctx' valid if it is not NULL, we should set it to NULL in this case to avoid to use an invalid pointer in other functions such as vhost_vdpa_config_put(). Fixes: 776f395004d8 ("vhost_vdpa: Support config interrupt in vdpa") Cc: lingshan.zhu@xxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> Link: https://lore.kernel.org/r/20210311135257.109460-3-sgarzare@xxxxxxxxxx Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Acked-by: Jason Wang <jasowang@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/vhost/vdpa.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -331,8 +331,12 @@ static long vhost_vdpa_set_config_call(s if (!IS_ERR_OR_NULL(ctx)) eventfd_ctx_put(ctx); - if (IS_ERR(v->config_ctx)) - return PTR_ERR(v->config_ctx); + if (IS_ERR(v->config_ctx)) { + long ret = PTR_ERR(v->config_ctx); + + v->config_ctx = NULL; + return ret; + } v->vdpa->config->set_config_cb(v->vdpa, &cb); Patches currently in stable-queue which might be from sgarzare@xxxxxxxxxx are queue-5.11/vhost-vdpa-set-v-config_ctx-to-null-if-eventfd_ctx_fdget-fails.patch queue-5.11/vhost-vdpa-fix-use-after-free-of-v-config_ctx.patch