kernel/linux.git/drivers/vhost/scsi.c, branch v5.10.263

use less confusing names for iov_iter direction initializers

2026-06-19T11:21:45+00:00

[ Upstream commit de4eda9de2d957ef2d6a8365a01e26a435e958cb ] READ/WRITE proved to be actively confusing - the meanings are "data destination, as used with read(2)" and "data source, as used with write(2)", but people keep interpreting those as "we read data from it" and "we write data to it", i.e. exactly the wrong way. Call them ITER_DEST and ITER_SOURCE - at least that is harder to misinterpret... Signed-off-by: Al Viro Stable-dep-of: a4f0b001782b ("vsock/virtio: reset connection on receiving queue overflow") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

vhost-scsi: Fix log flooding with target does not exist errors

2025-08-28T14:22:35+00:00

[ Upstream commit 69cd720a8a5e9ef0f05ce5dd8c9ea6e018245c82 ] As part of the normal initiator side scanning the guest's scsi layer will loop over all possible targets and send an inquiry. Since the max number of targets for virtio-scsi is 256, this can result in 255 error messages about targets not existing if you only have a single target. When there's more than 1 vhost-scsi device each with a single target, then you get N * 255 log messages. It looks like the log message was added by accident in: commit 3f8ca2e115e5 ("vhost/scsi: Extract common handling code from control queue handler") when we added common helpers. Then in: commit 09d7583294aa ("vhost/scsi: Use common handling code in request queue handler") we converted the scsi command processing path to use the new helpers so we started to see the extra log messages during scanning. The patches were just making some code common but added the vq_err call and I'm guessing the patch author forgot to enable the vq_err call (vq_err is implemented by pr_debug which defaults to off). So this patch removes the call since it's expected to hit this path during device discovery. Fixes: 09d7583294aa ("vhost/scsi: Use common handling code in request queue handler") Signed-off-by: Mike Christie Reviewed-by: Stefan Hajnoczi Reviewed-by: Stefano Garzarella Message-Id: <20250611210113.10912-1-michael.christie@oracle.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin

vhost-scsi: protect vq->log_used with vq->mutex

2025-07-17T16:28:00+00:00

commit f591cf9fce724e5075cc67488c43c6e39e8cbe27 upstream. The vhost-scsi completion path may access vq->log_base when vq->log_used is already set to false. vhost-thread QEMU-thread vhost_scsi_complete_cmd_work() -> vhost_add_used() -> vhost_add_used_n() if (unlikely(vq->log_used)) QEMU disables vq->log_used via VHOST_SET_VRING_ADDR. mutex_lock(&vq->mutex); vq->log_used = false now! mutex_unlock(&vq->mutex); QEMU gfree(vq->log_base) log_used() -> log_write(vq->log_base) Assuming the VMM is QEMU. The vq->log_base is from QEMU userpace and can be reclaimed via gfree(). As a result, this causes invalid memory writes to QEMU userspace. The control queue path has the same issue. Signed-off-by: Dongli Zhang Acked-by: Jason Wang Reviewed-by: Mike Christie Message-Id: <20250403063028.16045-2-dongli.zhang@oracle.com> Signed-off-by: Michael S. Tsirkin [ Resolved conflicts in drivers/vhost/scsi.c bacause vhost_scsi_complete_cmd_work() has been refactored. ] Signed-off-by: Xinyu Zheng Signed-off-by: Greg Kroah-Hartman

vhost/scsi: null-ptr-dereference in vhost_scsi_get_req()

2024-10-17T13:08:28+00:00

commit 221af82f606d928ccef19a16d35633c63026f1be upstream. Since commit 3f8ca2e115e5 ("vhost/scsi: Extract common handling code from control queue handler") a null pointer dereference bug can be triggered when guest sends an SCSI AN request. In vhost_scsi_ctl_handle_vq(), `vc.target` is assigned with `&v_req.tmf.lun[1]` within a switch-case block and is then passed to vhost_scsi_get_req() which extracts `vc->req` and `tpg`. However, for a `VIRTIO_SCSI_T_AN_*` request, tpg is not required, so `vc.target` is set to NULL in this branch. Later, in vhost_scsi_get_req(), `vc->target` is dereferenced without being checked, leading to a null pointer dereference bug. This bug can be triggered from guest. When this bug occurs, the vhost_worker process is killed while holding `vq->mutex` and the corresponding tpg will remain occupied indefinitely. Below is the KASAN report: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 PID: 840 Comm: poc Not tainted 6.10.0+ #1 Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:vhost_scsi_get_req+0x165/0x3a0 Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 2b 02 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 65 30 4c 89 e2 48 c1 ea 03 <0f> b6 04 02 4c 89 e2 83 e2 07 38 d0 7f 08 84 c0 0f 85 be 01 00 00 RSP: 0018:ffff888017affb50 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffff88801b000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888017affcb8 RBP: ffff888017affb80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffff888017affc88 R14: ffff888017affd1c R15: ffff888017993000 FS: 000055556e076500(0000) GS:ffff88806b100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000200027c0 CR3: 0000000010ed0004 CR4: 0000000000370ef0 Call Trace: ? show_regs+0x86/0xa0 ? die_addr+0x4b/0xd0 ? exc_general_protection+0x163/0x260 ? asm_exc_general_protection+0x27/0x30 ? vhost_scsi_get_req+0x165/0x3a0 vhost_scsi_ctl_handle_vq+0x2a4/0xca0 ? __pfx_vhost_scsi_ctl_handle_vq+0x10/0x10 ? __switch_to+0x721/0xeb0 ? __schedule+0xda5/0x5710 ? __kasan_check_write+0x14/0x30 ? _raw_spin_lock+0x82/0xf0 vhost_scsi_ctl_handle_kick+0x52/0x90 vhost_run_work_list+0x134/0x1b0 vhost_task_fn+0x121/0x350 ... ---[ end trace 0000000000000000 ]--- Let's add a check in vhost_scsi_get_req. Fixes: 3f8ca2e115e5 ("vhost/scsi: Extract common handling code from control queue handler") Signed-off-by: Haoran Zhang [whitespace fixes] Signed-off-by: Mike Christie Message-Id: Signed-off-by: Michael S. Tsirkin Signed-off-by: Greg Kroah-Hartman

vhost scsi: fix error return code in vhost_scsi_set_endpoint()

2020-12-30T10:54:00+00:00

[ Upstream commit 2e1139d613c7fb0956e82f72a8281c0a475ad4f8 ] Fix to return a negative error code from the error handling case instead of 0, as done elsewhere in this function. Fixes: 25b98b64e284 ("vhost scsi: alloc cmds per vq instead of session") Reported-by: Hulk Robot Signed-off-by: Zhang Changzhong Link: https://lore.kernel.org/r/1607071411-33484-1-git-send-email-zhangchangzhong@huawei.com Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin

vhost scsi: fix lun reset completion handling

2020-11-25T09:22:13+00:00

vhost scsi owns the scsi se_cmd but lio frees the se_cmd->se_tmr before calling release_cmd, so while with normal cmd completion we can access the se_cmd from the vhost work, we can't do the same with se_cmd->se_tmr. This has us copy the tmf response in vhost_scsi_queue_tm_rsp to our internal vhost-scsi tmf struct for when it gets sent to the guest from our worker thread. Fixes: efd838fec17b ("vhost scsi: Add support for LUN resets.") Signed-off-by: Mike Christie Acked-by: Stefan Hajnoczi Link: https://lore.kernel.org/r/1605887459-3864-1-git-send-email-michael.christie@oracle.com Signed-off-by: Michael S. Tsirkin

vhost scsi: Add support for LUN resets.

2020-11-15T22:30:55+00:00

In newer versions of virtio-scsi we just reset the timer when an a command times out, so TMFs are never sent for the cmd time out case. However, in older kernels and for the TMF inject cases, we can still get resets and we end up just failing immediately so the guest might see the device get offlined and IO errors. For the older kernel cases, we want the same end result as the modern virtio-scsi driver where we let the lower levels fire their error handling and handle the problem. And at the upper levels we want to wait. This patch ties the LUN reset handling into the LIO TMF code which will just wait for outstanding commands to complete like we are doing in the modern virtio-scsi case. Note: I did not handle the ABORT case to keep this simple. For ABORTs LIO just waits on the cmd like how it does for the RESET case. If an ABORT fails, the guest OS ends up escalating to LUN RESET, so in the end we get the same behavior where we wait on the outstanding cmds. Signed-off-by: Mike Christie Link: https://lore.kernel.org/r/1604986403-4931-6-git-send-email-michael.christie@oracle.com Signed-off-by: Michael S. Tsirkin Acked-by: Stefan Hajnoczi

vhost scsi: add lun parser helper

2020-11-15T22:30:55+00:00

Move code to parse lun from req's lun_buf to helper, so tmf code can use it in the next patch. Signed-off-by: Mike Christie Reviewed-by: Paolo Bonzini Acked-by: Jason Wang Link: https://lore.kernel.org/r/1604986403-4931-5-git-send-email-michael.christie@oracle.com Signed-off-by: Michael S. Tsirkin Acked-by: Stefan Hajnoczi

vhost scsi: fix cmd completion race

2020-11-15T22:30:55+00:00

We might not do the final se_cmd put from vhost_scsi_complete_cmd_work. When the last put happens a little later then we could race where vhost_scsi_complete_cmd_work does vhost_signal, the guest runs and sends more IO, and vhost_scsi_handle_vq runs but does not find any free cmds. This patch has us delay completing the cmd until the last lio core ref is dropped. We then know that once we signal to the guest that the cmd is completed that if it queues a new command it will find a free cmd. Signed-off-by: Mike Christie Reviewed-by: Maurizio Lombardi Link: https://lore.kernel.org/r/1604986403-4931-4-git-send-email-michael.christie@oracle.com Signed-off-by: Michael S. Tsirkin Acked-by: Stefan Hajnoczi

vhost scsi: alloc cmds per vq instead of session

2020-11-15T22:30:55+00:00

We currently are limited to 256 cmds per session. This leads to problems where if the user has increased virtqueue_size to more than 2 or cmd_per_lun to more than 256 vhost_scsi_get_tag can fail and the guest will get IO errors. This patch moves the cmd allocation to per vq so we can easily match whatever the user has specified for num_queues and virtqueue_size/cmd_per_lun. It also makes it easier to control how much memory we preallocate. For cases, where perf is not as important and we can use the current defaults (1 vq and 128 cmds per vq) memory use from preallocate cmds is cut in half. For cases, where we are willing to use more memory for higher perf, cmd mem use will now increase as the num queues and queue depth increases. Signed-off-by: Mike Christie Link: https://lore.kernel.org/r/1604986403-4931-3-git-send-email-michael.christie@oracle.com Signed-off-by: Michael S. Tsirkin Reviewed-by: Maurizio Lombardi Acked-by: Stefan Hajnoczi