Anirudh Rayabharam e2ae38cf3d vhost: fix hung thread due to erroneous iotlb entries ... In vhost_iotlb_add_range_ctx(), range size can overflow to 0 when start is 0 and last is ULONG_MAX. One instance where it can happen is when userspace sends an IOTLB message with iova=size=uaddr=0 (vhost_process_iotlb_msg). So, an entry with size = 0, start = 0, last = ULONG_MAX ends up in the iotlb. Next time a packet is sent, iotlb_access_ok() loops indefinitely due to that erroneous entry. Call Trace: <TASK> iotlb_access_ok+0x21b/0x3e0 drivers/vhost/vhost.c:1340 vq_meta_prefetch+0xbc/0x280 drivers/vhost/vhost.c:1366 vhost_transport_do_send_pkt+0xe0/0xfd0 drivers/vhost/vsock.c:104 vhost_worker+0x23d/0x3d0 drivers/vhost/vhost.c:372 kthread+0x2e9/0x3a0 kernel/kthread.c:377 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK> Reported by syzbot at: https://syzkaller.appspot.com/bug?extid=0abd373e2e50d704db87 To fix this, do two things: 1. Return -EINVAL in vhost_chr_write_iter() when userspace asks to map a range with size 0. 2. Fix vhost_iotlb_add_range_ctx() to handle the range [0, ULONG_MAX] by splitting it into two entries. Fixes: 0bbe30668d ("vhost: factor out IOTLB") Reported-by: syzbot+0abd373e2e50d704db87@syzkaller.appspotmail.com Tested-by: syzbot+0abd373e2e50d704db87@syzkaller.appspotmail.com Signed-off-by: Anirudh Rayabharam <mail@anirudhrb.com> Link: https://lore.kernel.org/r/20220305095525.5145-1-mail@anirudhrb.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com>		2022-03-06 06:05:45 -05:00
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iotlb.c	vhost: fix hung thread due to erroneous iotlb entries	2022-03-06 06:05:45 -05:00
Kconfig	vhost_vdpa: implement IRQ offloading in vhost_vdpa	2020-08-05 11:08:42 -04:00
Makefile	vhost: introduce vDPA-based backend	2020-04-02 10:41:40 -04:00
net.c	vhost_net: fix OoB on sendmsg() failure.	2021-09-09 10:52:12 +01:00
scsi.c	vhost scsi: Convert to SPDX identifier	2021-09-05 16:23:08 -04:00
test.c	vhost/test: fix memory leak of vhost virtqueues	2022-01-14 18:50:53 -05:00
test.h	tools/virtio: Add --reset	2020-06-22 12:34:21 -04:00
vdpa.c	vdpa: factor out vdpa_set_features_unlocked for vdpa internal use	2022-03-04 11:56:33 -05:00
vhost.c	vhost: fix hung thread due to erroneous iotlb entries	2022-03-06 06:05:45 -05:00
vhost.h	vhost: fix up vhost_work coding style	2021-07-03 04:50:55 -04:00
vringh.c	vringh: Use wiov->used to check for read/write desc order	2021-08-11 06:44:24 -04:00
vsock.c	vhost/vsock: don't check owner in vhost_vsock_stop() while releasing	2022-02-23 12:32:33 +00:00