From 4a47d3a1ff10e564bf04f27ac14552df64f60cdf Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Mon, 23 Sep 2013 11:42:28 -0700 Subject: vhost/scsi: Use GFP_ATOMIC with percpu_ida_alloc for obtaining tag Fix GFP_KERNEL -> GFP_ATOMIC usage of percpu_ida_alloc() within vhost_scsi_get_tag(), as this code is expected to be called directly from interrupt context. v2 changes: - Handle possible tag < 0 failure with GFP_ATOMIC Acked-by: Michael S. Tsirkin Acked-by: Asias He Cc: Kent Overstreet Signed-off-by: Nicholas Bellinger --- drivers/vhost/scsi.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'drivers/vhost/scsi.c') diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 592b31698fc..ce5221fa393 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -728,7 +728,12 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq, } se_sess = tv_nexus->tvn_se_sess; - tag = percpu_ida_alloc(&se_sess->sess_tag_pool, GFP_KERNEL); + tag = percpu_ida_alloc(&se_sess->sess_tag_pool, GFP_ATOMIC); + if (tag < 0) { + pr_err("Unable to obtain tag for tcm_vhost_cmd\n"); + return ERR_PTR(-ENOMEM); + } + cmd = &((struct tcm_vhost_cmd *)se_sess->sess_cmd_map)[tag]; sg = cmd->tvc_sgl; pages = cmd->tvc_upages; -- cgit v1.2.3-70-g09d2 From 60a01f558af9c48b0bb31f303c479e32721add3f Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Fri, 25 Oct 2013 10:44:15 -0700 Subject: vhost/scsi: Fix incorrect usage of get_user_pages_fast write parameter This patch addresses a long-standing bug where the get_user_pages_fast() write parameter used for setting the underlying page table entry permission bits was incorrectly set to write=1 for data_direction=DMA_TO_DEVICE, and passed into get_user_pages_fast() via vhost_scsi_map_iov_to_sgl(). However, this parameter is intended to signal WRITEs to pinned userspace PTEs for the virtio-scsi DMA_FROM_DEVICE -> READ payload case, and *not* for the virtio-scsi DMA_TO_DEVICE -> WRITE payload case. This bug would manifest itself as random process segmentation faults on KVM host after repeated vhost starts + stops and/or with lots of vhost endpoints + LUNs. Cc: Stefan Hajnoczi Cc: Michael S. Tsirkin Cc: Asias He Cc: # 3.6+ Signed-off-by: Nicholas Bellinger --- drivers/vhost/scsi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/vhost/scsi.c') diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index ce5221fa393..e663921eebb 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -1056,7 +1056,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq) if (data_direction != DMA_NONE) { ret = vhost_scsi_map_iov_to_sgl(cmd, &vq->iov[data_first], data_num, - data_direction == DMA_TO_DEVICE); + data_direction == DMA_FROM_DEVICE); if (unlikely(ret)) { vq_err(vq, "Failed to map iov to sgl\n"); goto err_free; -- cgit v1.2.3-70-g09d2