linux-stable.git/drivers/virtio, branch v6.12.96

virtio-mmio: fix device release warning on module unload

2026-07-18T14:52:00+00:00

commit c687bc35694698ec4c7f92bf929c3d659f0cecb8 upstream.

Driver core expects devices to be allocated dynamically and complains
loudly when a device that lacks a release function is freed.

Use __root_device_register() to allocate and register the root device
instead of open coding using a static device.

Note that root_device_register(), which also creates a link to the
module, cannot be used as the device is registered when parsing the
module parameters which happens before the module kobject has been set
up.

Fixes: 81a054ce0b46 ("virtio-mmio: Devices parameter parsing")
Cc: stable@vger.kernel.org	# 3.5
Cc: Pawel Moll 
Signed-off-by: Johan Hovold 
Signed-off-by: Michael S. Tsirkin 
Message-ID: <20260427143710.14702-1-johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman

virtio_pci: fix vq info pointer lookup via wrong index

2026-07-18T14:52:00+00:00

commit f7d380fb525c13bdd114369a1979c80c346e6abc upstream.

Unbinding a virtio balloon device:

    echo virtio0 > /sys/bus/virtio/drivers/virtio_balloon/unbind

triggers a NULL pointer dereference. The dmesg says:

    BUG: kernel NULL pointer dereference, address: 0000000000000008
    [...]
    RIP: 0010:__list_del_entry_valid_or_report+0x5/0xf0
    Call Trace:
    
    vp_del_vqs+0x121/0x230
    remove_common+0x135/0x150
    virtballoon_remove+0xee/0x100
    virtio_dev_remove+0x3b/0x80
    device_release_driver_internal+0x187/0x2c0
    unbind_store+0xb9/0xe0
    kernfs_fop_write_iter.llvm.11660790530567441834+0xf6/0x180
    vfs_write+0x2a9/0x3b0
    ksys_write+0x5c/0xd0
    do_syscall_64+0x54/0x230
    entry_SYSCALL_64_after_hwframe+0x29/0x31
    [...]
    

The virtio_balloon device registers 5 queues (inflate, deflate, stats,
free_page, reporting) but only the first two are unconditional. The
stats, free_page and reporting queues are each conditional on their
respective feature bits. When any of these features are absent, the
corresponding vqs_info entry has name == NULL, creating holes in the
array.

The root cause is an indexing mismatch introduced when vq info storage
was changed to be passed as an argument. vp_find_vqs_msix() and
vp_find_vqs_intx() store the info pointer at vp_dev->vqs[i], where 'i'
is the caller's sparse array index. However, the virtqueue itself gets
vq->index assigned from queue_idx, a dense index that skips NULL
entries. When holes exist, 'i' and queue_idx diverge. Later,
vp_del_vqs() looks up info via vp_dev->vqs[vq->index] using the dense
index into the sparsely-populated array, and hits NULL.

Fix this by storing info at vp_dev->vqs[queue_idx] instead of
vp_dev->vqs[i], so the store index matches the lookup index
(vq->index). Apply the fix to both the MSIX and INTX paths.

Cc: Yichun Zhang 
Cc: Jiri Pirko 
Cc: stable@vger.kernel.org # v6.11+
Tested-by: Yuka 
Fixes: 89a1c435aec2 ("virtio_pci: pass vq info as an argument to vp_setup_vq()")
Signed-off-by: Ammar Faizi 
Message-Id: <20260315141808.547081-1-ammarfaizi2@openresty.com>
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Greg Kroah-Hartman

mm/balloon_compaction: convert balloon_page_delete() to balloon_page_finalize()

2026-01-08T09:15:05+00:00

[ Upstream commit 15504b1163007bbfbd9a63460d5c14737c16e96d ]

Let's move the removal of the page from the balloon list into the single
caller, to remove the dependency on the PG_isolated flag and clarify
locking requirements.

Note that for now, balloon_page_delete() was used on two paths:

(1) Removing a page from the balloon for deflation through
    balloon_page_list_dequeue()
(2) Removing an isolated page from the balloon for migration in the
    per-driver migration handlers. Isolated pages were already removed from
    the balloon list during isolation.

So instead of relying on the flag, we can just distinguish both cases
directly and handle it accordingly in the caller.

We'll shuffle the operations a bit such that they logically make more
sense (e.g., remove from the list before clearing flags).

In balloon migration functions we can now move the balloon_page_finalize()
out of the balloon lock and perform the finalization just before dropping
the balloon reference.

Document that the page lock is currently required when modifying the
movability aspects of a page; hopefully we can soon decouple this from the
page lock.

Link: https://lkml.kernel.org/r/20250704102524.326966-3-david@redhat.com
Signed-off-by: David Hildenbrand 
Reviewed-by: Lorenzo Stoakes 
Cc: Alistair Popple 
Cc: Al Viro 
Cc: Arnd Bergmann 
Cc: Brendan Jackman 
Cc: Byungchul Park 
Cc: Chengming Zhou 
Cc: Christian Brauner 
Cc: Christophe Leroy 
Cc: Eugenio Pé rez 
Cc: Greg Kroah-Hartman 
Cc: Gregory Price 
Cc: Harry Yoo 
Cc: "Huang, Ying" 
Cc: Jan Kara 
Cc: Jason Gunthorpe 
Cc: Jason Wang 
Cc: Jerrin Shaji George 
Cc: Johannes Weiner 
Cc: John Hubbard 
Cc: Jonathan Corbet 
Cc: Joshua Hahn 
Cc: Liam Howlett 
Cc: Madhavan Srinivasan 
Cc: Mathew Brost 
Cc: Matthew Wilcox (Oracle) 
Cc: Miaohe Lin 
Cc: Michael Ellerman 
Cc: "Michael S. Tsirkin" 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Minchan Kim 
Cc: Naoya Horiguchi 
Cc: Nicholas Piggin 
Cc: Oscar Salvador 
Cc: Peter Xu 
Cc: Qi Zheng 
Cc: Rakie Kim 
Cc: Rik van Riel 
Cc: Sergey Senozhatsky 
Cc: Shakeel Butt 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Cc: Xuan Zhuo 
Cc: xu xin 
Cc: Zi Yan 
Signed-off-by: Andrew Morton 
Stable-dep-of: 0da2ba35c0d5 ("powerpc/pseries/cmm: adjust BALLOON_MIGRATE when migrating pages")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

virtio_vdpa: fix misleading return in void function

2025-12-18T12:55:09+00:00

[ Upstream commit e40b6abe0b1247d43bc61942aa7534fca7209e44 ]

virtio_vdpa_set_status() is declared as returning void, but it used
"return vdpa_set_status()" Since vdpa_set_status() also returns
void, the return statement is unnecessary and misleading.
Remove it.

Fixes: c043b4a8cf3b ("virtio: introduce a vDPA based transport")
Signed-off-by: Alok Tiwari 
Message-Id: <20251001191653.1713923-1-alok.a.tiwari@oracle.com>
Signed-off-by: Michael S. Tsirkin 
Acked-by: Jason Wang 
Signed-off-by: Sasha Levin

virtio_ring: Fix error reporting in virtqueue_resize

2025-08-01T08:48:39+00:00

[ Upstream commit 45ebc7e6c125ce93d2ddf82cd5bea20121bb0258 ]

The virtqueue_resize() function was not correctly propagating error codes
from its internal resize helper functions, specifically
virtqueue_resize_packet() and virtqueue_resize_split(). If these helpers
returned an error, but the subsequent call to virtqueue_enable_after_reset()
succeeded, the original error from the resize operation would be masked.
Consequently, virtqueue_resize() could incorrectly report success to its
caller despite an underlying resize failure.

This change restores the original code behavior:

       if (vdev->config->enable_vq_after_reset(_vq))
               return -EBUSY;

       return err;

Fix: commit ad48d53b5b3f ("virtio_ring: separate the logic of reset/enable from virtqueue_resize")
Cc: xuanzhuo@linux.alibaba.com
Signed-off-by: Laurent Vivier 
Acked-by: Jason Wang 
Link: https://patch.msgid.link/20250521092236.661410-2-lvivier@redhat.com
Tested-by: Lei Yang 
Acked-by: Michael S. Tsirkin 
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

virtio_ring: Fix data race by tagging event_triggered as racy for KCSAN

2025-05-29T09:01:58+00:00

[ Upstream commit 2e2f925fe737576df2373931c95e1a2b66efdfef ]

syzbot reports a data-race when accessing the event_triggered, here is the
simplified stack when the issue occurred:

==================================================================
BUG: KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed

write to 0xffff8881025bc452 of 1 bytes by task 3288 on cpu 0:
 virtqueue_enable_cb_delayed+0x42/0x3c0 drivers/virtio/virtio_ring.c:2653
 start_xmit+0x230/0x1310 drivers/net/virtio_net.c:3264
 __netdev_start_xmit include/linux/netdevice.h:5151 [inline]
 netdev_start_xmit include/linux/netdevice.h:5160 [inline]
 xmit_one net/core/dev.c:3800 [inline]

read to 0xffff8881025bc452 of 1 bytes by interrupt on cpu 1:
 virtqueue_disable_cb_split drivers/virtio/virtio_ring.c:880 [inline]
 virtqueue_disable_cb+0x92/0x180 drivers/virtio/virtio_ring.c:2566
 skb_xmit_done+0x5f/0x140 drivers/net/virtio_net.c:777
 vring_interrupt+0x161/0x190 drivers/virtio/virtio_ring.c:2715
 __handle_irq_event_percpu+0x95/0x490 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]

value changed: 0x01 -> 0x00
==================================================================

When the data race occurs, the function virtqueue_enable_cb_delayed() sets
event_triggered to false, and virtqueue_disable_cb_split/packed() reads it
as false due to the race condition. Since event_triggered is an unreliable
hint used for optimization, this should only cause the driver temporarily
suggest that the device not send an interrupt notification when the event
index is used.

Fix this KCSAN reported data-race issue by explicitly tagging the access as
data_racy.

Reported-by: syzbot+efe683d57990864b8c8e@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/67c7761a.050a0220.15b4b9.0018.GAE@google.com/
Signed-off-by: Zhongqiu Han 
Message-Id: <20250312130412.3516307-1-quic_zhonhan@quicinc.com>
Signed-off-by: Michael S. Tsirkin 
Acked-by: Jason Wang 
Signed-off-by: Sasha Levin

virtio_ring: add a func argument 'recycle_done' to virtqueue_reset()

2025-05-22T12:29:38+00:00

[ Upstream commit 8d2da07c813ad333c20eb803e15f8c4541f25350 ]

When virtqueue_reset() has actually recycled all unused buffers,
additional work may be required in some cases. Relying solely on its
return status is fragile, so introduce a new function argument
'recycle_done', which is invoked when it really occurs.

Signed-off-by: Koichiro Den 
Acked-by: Jason Wang 
Reviewed-by: Xuan Zhuo 
Signed-off-by: Paolo Abeni 
Stable-dep-of: 76a771ec4c9a ("virtio_net: ensure netdev_tx_reset_queue is called on bind xsk for tx")
Signed-off-by: Sasha Levin

virtio_ring: add a func argument 'recycle_done' to virtqueue_resize()

2024-12-19T17:12:59+00:00

commit 8d6712c892019b9b9dc5c7039edd3c9d770b510b upstream.

When virtqueue_resize() has actually recycled all unused buffers,
additional work may be required in some cases. Relying solely on its
return status is fragile, so introduce a new function argument
'recycle_done', which is invoked when the recycle really occurs.

Cc:  # v6.11+
Signed-off-by: Koichiro Den 
Acked-by: Jason Wang 
Reviewed-by: Xuan Zhuo 
Signed-off-by: Paolo Abeni 
Signed-off-by: Greg Kroah-Hartman

virtio_pci: Fix admin vq cleanup by using correct info pointer

2024-11-06T09:40:07+00:00

vp_modern_avq_cleanup() and vp_del_vqs() clean up admin vq
resources by virtio_pci_vq_info pointer. The info pointer of admin
vq is stored in vp_dev->admin_vq.info instead of vp_dev->vqs[].
Using the info pointer from vp_dev->vqs[] for admin vq causes a
kernel NULL pointer dereference bug.
In vp_modern_avq_cleanup() and vp_del_vqs(), get the info pointer
from vp_dev->admin_vq.info for admin vq to clean up the resources.
Also make info ptr as argument of vp_del_vq() to be symmetric with
vp_setup_vq().

vp_reset calls vp_modern_avq_cleanup, and causes the Call Trace:
==================================================================
BUG: kernel NULL pointer dereference, address:0000000000000000
...
CPU: 49 UID: 0 PID: 4439 Comm: modprobe Not tainted 6.11.0-rc5 #1
RIP: 0010:vp_reset+0x57/0x90 [virtio_pci]
Call Trace:
 
...
 ? vp_reset+0x57/0x90 [virtio_pci]
 ? vp_reset+0x38/0x90 [virtio_pci]
 virtio_reset_device+0x1d/0x30
 remove_vq_common+0x1c/0x1a0 [virtio_net]
 virtnet_remove+0xa1/0xc0 [virtio_net]
 virtio_dev_remove+0x46/0xa0
...
 virtio_pci_driver_exit+0x14/0x810 [virtio_pci]
==================================================================

Fixes: 4c3b54af907e ("virtio_pci_modern: use completion instead of busy loop to wait on admin cmd result")
Signed-off-by: Feng Liu 
Signed-off-by: Jiri Pirko 
Reviewed-by: Parav Pandit 
Message-Id: <20241024135406.81388-1-feliu@nvidia.com>
Signed-off-by: Michael S. Tsirkin

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