kernel/linux.git/drivers/vhost/scsi.c, branch v6.12.80

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

2025-08-15T10:13:58+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: Return queue full for page alloc failures during copy

2025-05-29T09:02:38+00:00

[ Upstream commit 891b99eab0f89dbe08d216f4ab71acbeaf7a3102 ] This has us return queue full if we can't allocate a page during the copy operation so the initiator can retry. Signed-off-by: Mike Christie Message-Id: <20241203191705.19431-5-michael.christie@oracle.com> Signed-off-by: Michael S. Tsirkin Acked-by: Stefan Hajnoczi Signed-off-by: Sasha Levin

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

2025-05-29T09:01:59+00:00

[ Upstream commit f591cf9fce724e5075cc67488c43c6e39e8cbe27 ] 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 Signed-off-by: Sasha Levin

vhost-scsi: Fix vhost_scsi_send_status()

2025-05-02T05:59:01+00:00

[ Upstream commit 58465d86071b61415e25fb054201f61e83d21465 ] Although the support of VIRTIO_F_ANY_LAYOUT + VIRTIO_F_VERSION_1 was signaled by the commit 664ed90e621c ("vhost/scsi: Set VIRTIO_F_ANY_LAYOUT + VIRTIO_F_VERSION_1 feature bits"), vhost_scsi_send_bad_target() still assumes the response in a single descriptor. Similar issue in vhost_scsi_send_bad_target() has been fixed in previous commit. In addition, similar issue for vhost_scsi_complete_cmd_work() has been fixed by the commit 6dd88fd59da8 ("vhost-scsi: unbreak any layout for response"). Fixes: 3ca51662f818 ("vhost-scsi: Add better resource allocation failure handling") Signed-off-by: Dongli Zhang Acked-by: Jason Wang Reviewed-by: Mike Christie Message-Id: <20250403063028.16045-4-dongli.zhang@oracle.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin

vhost-scsi: Fix vhost_scsi_send_bad_target()

2025-05-02T05:59:01+00:00

[ Upstream commit b182687135474d7ed905a07cc6cb2734b359e13e ] Although the support of VIRTIO_F_ANY_LAYOUT + VIRTIO_F_VERSION_1 was signaled by the commit 664ed90e621c ("vhost/scsi: Set VIRTIO_F_ANY_LAYOUT + VIRTIO_F_VERSION_1 feature bits"), vhost_scsi_send_bad_target() still assumes the response in a single descriptor. In addition, although vhost_scsi_send_bad_target() is used by both I/O queue and control queue, the response header is always virtio_scsi_cmd_resp. It is required to use virtio_scsi_ctrl_tmf_resp or virtio_scsi_ctrl_an_resp for control queue. Fixes: 664ed90e621c ("vhost/scsi: Set VIRTIO_F_ANY_LAYOUT + VIRTIO_F_VERSION_1 feature bits") Signed-off-by: Dongli Zhang Acked-by: Jason Wang Reviewed-by: Mike Christie Message-Id: <20250403063028.16045-3-dongli.zhang@oracle.com> Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin

vhost-scsi: Add better resource allocation failure handling

2025-05-02T05:59:00+00:00

[ Upstream commit 3ca51662f8186b569b8fb282242c20ccbb3993c2 ] If we can't allocate mem to map in data for a request or can't find a tag for a command, we currently drop the command. This leads to the error handler running to clean it up. Instead of dropping the command this has us return an error telling the initiator that it queued more commands than we can handle. The initiator will then reduce how many commands it will send us and retry later. Signed-off-by: Mike Christie Message-Id: <20241203191705.19431-4-michael.christie@oracle.com> Signed-off-by: Michael S. Tsirkin Acked-by: Stefan Hajnoczi Stable-dep-of: b18268713547 ("vhost-scsi: Fix vhost_scsi_send_bad_target()") Signed-off-by: Sasha Levin

vhost-scsi: Fix handling of multiple calls to vhost_scsi_set_endpoint

2025-04-10T12:39:22+00:00

[ Upstream commit 5dd639a1646ef5fe8f4bf270fad47c5c3755b9b6 ] If vhost_scsi_set_endpoint is called multiple times without a vhost_scsi_clear_endpoint between them, we can hit multiple bugs found by Haoran Zhang: 1. Use-after-free when no tpgs are found: This fixes a use after free that occurs when vhost_scsi_set_endpoint is called more than once and calls after the first call do not find any tpgs to add to the vs_tpg. When vhost_scsi_set_endpoint first finds tpgs to add to the vs_tpg array match=true, so we will do: vhost_vq_set_backend(vq, vs_tpg); ... kfree(vs->vs_tpg); vs->vs_tpg = vs_tpg; If vhost_scsi_set_endpoint is called again and no tpgs are found match=false so we skip the vhost_vq_set_backend call leaving the pointer to the vs_tpg we then free via: kfree(vs->vs_tpg); vs->vs_tpg = vs_tpg; If a scsi request is then sent we do: vhost_scsi_handle_vq -> vhost_scsi_get_req -> vhost_vq_get_backend which sees the vs_tpg we just did a kfree on. 2. Tpg dir removal hang: This patch fixes an issue where we cannot remove a LIO/target layer tpg (and structs above it like the target) dir due to the refcount dropping to -1. The problem is that if vhost_scsi_set_endpoint detects a tpg is already in the vs->vs_tpg array or if the tpg has been removed so target_depend_item fails, the undepend goto handler will do target_undepend_item on all tpgs in the vs_tpg array dropping their refcount to 0. At this time vs_tpg contains both the tpgs we have added in the current vhost_scsi_set_endpoint call as well as tpgs we added in previous calls which are also in vs->vs_tpg. Later, when vhost_scsi_clear_endpoint runs it will do target_undepend_item on all the tpgs in the vs->vs_tpg which will drop their refcount to -1. Userspace will then not be able to remove the tpg and will hang when it tries to do rmdir on the tpg dir. 3. Tpg leak: This fixes a bug where we can leak tpgs and cause them to be un-removable because the target name is overwritten when vhost_scsi_set_endpoint is called multiple times but with different target names. The bug occurs if a user has called VHOST_SCSI_SET_ENDPOINT and setup a vhost-scsi device to target/tpg mapping, then calls VHOST_SCSI_SET_ENDPOINT again with a new target name that has tpgs we haven't seen before (target1 has tpg1 but target2 has tpg2). When this happens we don't teardown the old target tpg mapping and just overwrite the target name and the vs->vs_tpg array. Later when we do vhost_scsi_clear_endpoint, we are passed in either target1 or target2's name and we will only match that target's tpgs when we loop over the vs->vs_tpg. We will then return from the function without doing target_undepend_item on the tpgs. Because of all these bugs, it looks like being able to call vhost_scsi_set_endpoint multiple times was never supported. The major user, QEMU, already has checks to prevent this use case. So to fix the issues, this patch prevents vhost_scsi_set_endpoint from being called if it's already successfully added tpgs. To add, remove or change the tpg config or target name, you must do a vhost_scsi_clear_endpoint first. Fixes: 25b98b64e284 ("vhost scsi: alloc cmds per vq instead of session") Fixes: 4f7f46d32c98 ("tcm_vhost: Use vq->private_data to indicate if the endpoint is setup") Reported-by: Haoran Zhang Closes: https://lore.kernel.org/virtualization/e418a5ee-45ca-4d18-9b5d-6f8b6b1add8e@oracle.com/T/#me6c0041ce376677419b9b2563494172a01487ecb Signed-off-by: Mike Christie Reviewed-by: Stefan Hajnoczi Message-Id: <20250129210922.121533-1-michael.christie@oracle.com> Signed-off-by: Michael S. Tsirkin Acked-by: Stefano Garzarella Signed-off-by: Sasha Levin

Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

2024-10-07T18:33:26+00:00

Pull virtio fixes from Michael Tsirkin: "Several small bugfixes all over the place. Most notably, fixes the vsock allocation with GFP_KERNEL in atomic context, which has been triggering warnings for lots of testers" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: vhost/scsi: null-ptr-dereference in vhost_scsi_get_req() vsock/virtio: use GFP_ATOMIC under RCU read lock virtio_console: fix misc probe bugs virtio_ring: tag event_triggered as racy for KCSAN vdpa/octeon_ep: Fix format specifier for pointers in debug messages

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

2024-10-07T15:47:56+00:00

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

move asm/unaligned.h to linux/unaligned.h

2024-10-02T21:23:23+00:00

asm/unaligned.h is always an include of asm-generic/unaligned.h; might as well move that thing to linux/unaligned.h and include that - there's nothing arch-specific in that header. auto-generated by the following: for i in `git grep -l -w asm/unaligned.h`; do sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i done for i in `git grep -l -w asm-generic/unaligned.h`; do sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i done git mv include/asm-generic/unaligned.h include/linux/unaligned.h git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h