linux.git/include, branch v6.6.120

tty: fix tty_port_tty_*hangup() kernel-doc

2026-01-11T14:22:33+00:00

commit 6241b49540a65a6d5274fa938fd3eb4cbfe2e076 upstream.

The commit below added a new helper, but omitted to move (and add) the
corressponding kernel-doc. Do it now.

Signed-off-by: "Jiri Slaby (SUSE)" 
Fixes: 2b5eac0f8c6e ("tty: introduce and use tty_port_tty_vhangup() helper")
Link: https://lore.kernel.org/all/b23d566c-09dc-7374-cc87-0ad4660e8b2e@linux.intel.com/
Reported-by: Ilpo Järvinen 
Cc: Jonathan Corbet 
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/20250624080641.509959-6-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

RDMA/rxe: Remove the direct link to net_device

2026-01-11T14:22:31+00:00

[ Upstream commit 2ac5415022d16d63d912a39a06f32f1f51140261 ]

The similar patch in siw is in the link:
https://git.kernel.org/rdma/rdma/c/16b87037b48889

This problem also occurred in RXE. The following analyze this problem.
In the following Call Traces:
"
BUG: KASAN: slab-use-after-free in dev_get_flags+0x188/0x1d0 net/core/dev.c:8782
Read of size 4 at addr ffff8880554640b0 by task kworker/1:4/5295

CPU: 1 UID: 0 PID: 5295 Comm: kworker/1:4 Not tainted
6.12.0-rc3-syzkaller-00399-g9197b73fd7bb #0
Hardware name: Google Compute Engine/Google Compute Engine,
BIOS Google 09/13/2024
Workqueue: infiniband ib_cache_event_task
Call Trace:
 
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 dev_get_flags+0x188/0x1d0 net/core/dev.c:8782
 rxe_query_port+0x12d/0x260 drivers/infiniband/sw/rxe/rxe_verbs.c:60
 __ib_query_port drivers/infiniband/core/device.c:2111 [inline]
 ib_query_port+0x168/0x7d0 drivers/infiniband/core/device.c:2143
 ib_cache_update+0x1a9/0xb80 drivers/infiniband/core/cache.c:1494
 ib_cache_event_task+0xf3/0x1e0 drivers/infiniband/core/cache.c:1568
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 
"

1). In the link [1],

"
 infiniband syz2: set down
"

This means that on 839.350575, the event ib_cache_event_task was sent andi
queued in ib_wq.

2). In the link [1],

"
 team0 (unregistering): Port device team_slave_0 removed
"

It indicates that before 843.251853, the net device should be freed.

3). In the link [1],

"
 BUG: KASAN: slab-use-after-free in dev_get_flags+0x188/0x1d0
"

This means that on 850.559070, this slab-use-after-free problem occurred.

In all, on 839.350575, the event ib_cache_event_task was sent and queued
in ib_wq,

before 843.251853, the net device veth was freed.

on 850.559070, this event was executed, and the mentioned freed net device
was called. Thus, the above call trace occurred.

[1] https://syzkaller.appspot.com/x/log.txt?x=12e7025f980000

Reported-by: syzbot+4b87489410b4efd181bf@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=4b87489410b4efd181bf
Fixes: 8700e3e7c485 ("Soft RoCE driver")
Signed-off-by: Zhu Yanjun 
Link: https://patch.msgid.link/20241220222325.2487767-1-yanjun.zhu@linux.dev
Signed-off-by: Leon Romanovsky 
Signed-off-by: Sasha Levin 
[Shivani: - exported ib_device_get_netdev() function.
          - added ib_device_get_netdev() to ib_verbs.h.]
Signed-off-by: Shivani Agarwal 
Signed-off-by: Greg Kroah-Hartman

sched/fair: Proportional newidle balance

2026-01-11T14:22:30+00:00

commit 33cf66d88306663d16e4759e9d24766b0aaa2e17 upstream.

Add a randomized algorithm that runs newidle balancing proportional to
its success rate.

This improves schbench significantly:

 6.18-rc4:			2.22 Mrps/s
 6.18-rc4+revert:		2.04 Mrps/s
 6.18-rc4+revert+random:	2.18 Mrps/S

Conversely, per Adam Li this affects SpecJBB slightly, reducing it by 1%:

 6.17:			-6%
 6.17+revert:		 0%
 6.17+revert+random:	-1%

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Dietmar Eggemann 
Tested-by: Dietmar Eggemann 
Tested-by: Chris Mason 
Link: https://lkml.kernel.org/r/6825c50d-7fa7-45d8-9b81-c6e7e25738e2@meta.com
Link: https://patch.msgid.link/20251107161739.770122091@infradead.org
[ Ajay: Modified to apply on v6.6 ]
Signed-off-by: Ajay Kaher 
Signed-off-by: Greg Kroah-Hartman

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

2026-01-11T14:22:28+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

net: Remove RTNL dance for SIOCBRADDIF and SIOCBRDELIF.

2026-01-11T14:22:25+00:00

commit ed3ba9b6e280e14cc3148c1b226ba453f02fa76c upstream.

SIOCBRDELIF is passed to dev_ioctl() first and later forwarded to
br_ioctl_call(), which causes unnecessary RTNL dance and the splat
below [0] under RTNL pressure.

Let's say Thread A is trying to detach a device from a bridge and
Thread B is trying to remove the bridge.

In dev_ioctl(), Thread A bumps the bridge device's refcnt by
netdev_hold() and releases RTNL because the following br_ioctl_call()
also re-acquires RTNL.

In the race window, Thread B could acquire RTNL and try to remove
the bridge device.  Then, rtnl_unlock() by Thread B will release RTNL
and wait for netdev_put() by Thread A.

Thread A, however, must hold RTNL after the unlock in dev_ifsioc(),
which may take long under RTNL pressure, resulting in the splat by
Thread B.

  Thread A (SIOCBRDELIF)           Thread B (SIOCBRDELBR)
  ----------------------           ----------------------
  sock_ioctl                       sock_ioctl
  `- sock_do_ioctl                 `- br_ioctl_call
     `- dev_ioctl                     `- br_ioctl_stub
        |- rtnl_lock                     |
        |- dev_ifsioc                    '
        '  |- dev = __dev_get_by_name(...)
           |- netdev_hold(dev, ...)      .
       /   |- rtnl_unlock  ------.       |
       |   |- br_ioctl_call       `--->  |- rtnl_lock
  Race |   |  `- br_ioctl_stub           |- br_del_bridge
  Window   |     |                       |  |- dev = __dev_get_by_name(...)
       |   |     |  May take long        |  `- br_dev_delete(dev, ...)
       |   |     |  under RTNL pressure  |     `- unregister_netdevice_queue(dev, ...)
       |   |     |               |       `- rtnl_unlock
       \   |     |- rtnl_lock  <-'          `- netdev_run_todo
           |     |- ...                        `- netdev_run_todo
           |     `- rtnl_unlock                   |- __rtnl_unlock
           |                                      |- netdev_wait_allrefs_any
           |- netdev_put(dev, ...)  <----------------'
                                                Wait refcnt decrement
                                                and log splat below

To avoid blocking SIOCBRDELBR unnecessarily, let's not call
dev_ioctl() for SIOCBRADDIF and SIOCBRDELIF.

In the dev_ioctl() path, we do the following:

  1. Copy struct ifreq by get_user_ifreq in sock_do_ioctl()
  2. Check CAP_NET_ADMIN in dev_ioctl()
  3. Call dev_load() in dev_ioctl()
  4. Fetch the master dev from ifr.ifr_name in dev_ifsioc()

3. can be done by request_module() in br_ioctl_call(), so we move
1., 2., and 4. to br_ioctl_stub().

Note that 2. is also checked later in add_del_if(), but it's better
performed before RTNL.

SIOCBRADDIF and SIOCBRDELIF have been processed in dev_ioctl() since
the pre-git era, and there seems to be no specific reason to process
them there.

[0]:
unregister_netdevice: waiting for wpan3 to become free. Usage count = 2
ref_tracker: wpan3@ffff8880662d8608 has 1/1 users at
     __netdev_tracker_alloc include/linux/netdevice.h:4282 [inline]
     netdev_hold include/linux/netdevice.h:4311 [inline]
     dev_ifsioc+0xc6a/0x1160 net/core/dev_ioctl.c:624
     dev_ioctl+0x255/0x10c0 net/core/dev_ioctl.c:826
     sock_do_ioctl+0x1ca/0x260 net/socket.c:1213
     sock_ioctl+0x23a/0x6c0 net/socket.c:1318
     vfs_ioctl fs/ioctl.c:51 [inline]
     __do_sys_ioctl fs/ioctl.c:906 [inline]
     __se_sys_ioctl fs/ioctl.c:892 [inline]
     __x64_sys_ioctl+0x1a4/0x210 fs/ioctl.c:892
     do_syscall_x64 arch/x86/entry/common.c:52 [inline]
     do_syscall_64+0xcb/0x250 arch/x86/entry/common.c:83
     entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fixes: 893b19587534 ("net: bridge: fix ioctl locking")
Reported-by: syzkaller 
Reported-by: yan kang 
Reported-by: yue sun 
Closes: https://lore.kernel.org/netdev/SY8P300MB0421225D54EB92762AE8F0F2A1D32@SY8P300MB0421.AUSP300.PROD.OUTLOOK.COM/
Signed-off-by: Kuniyuki Iwashima 
Acked-by: Stanislav Fomichev 
Reviewed-by: Ido Schimmel 
Acked-by: Nikolay Aleksandrov 
Link: https://patch.msgid.link/20250316192851.19781-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni 
[cascardo: fixed conflict at dev_ifsioc]
Signed-off-by: Thadeu Lima de Souza Cascardo 
Signed-off-by: Greg Kroah-Hartman

tty: introduce and use tty_port_tty_vhangup() helper

2026-01-11T14:22:25+00:00

[ Upstream commit 2b5eac0f8c6e79bc152c8804f9f88d16717013ab ]

This code (tty_get -> vhangup -> tty_put) is repeated on few places.
Introduce a helper similar to tty_port_tty_hangup() (asynchronous) to
handle even vhangup (synchronous).

And use it on those places.

In fact, reuse the tty_port_tty_hangup()'s code and call tty_vhangup()
depending on a new bool parameter.

Signed-off-by: "Jiri Slaby (SUSE)" 
Cc: Karsten Keil 
Cc: David Lin 
Cc: Johan Hovold 
Cc: Alex Elder 
Cc: Oliver Neukum 
Cc: Marcel Holtmann 
Cc: Johan Hedberg 
Cc: Luiz Augusto von Dentz 
Reviewed-by: Ilpo Järvinen 
Link: https://lore.kernel.org/r/20250611100319.186924-2-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman 
Stable-dep-of: 74098cc06e75 ("xhci: dbgtty: fix device unregister: fixup")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mm: consider non-anon swap cache folios in folio_expected_ref_count()

2026-01-11T14:22:24+00:00

[ Upstream commit f183663901f21fe0fba8bd31ae894bc529709ee0 ]

Currently, folio_expected_ref_count() only adds references for the swap
cache if the folio is anonymous.  However, according to the comment above
the definition of PG_swapcache in enum pageflags, shmem folios can also
have PG_swapcache set.  This patch makes sure references for the swap
cache are added if folio_test_swapcache(folio) is true.

This issue was found when trying to hot-unplug memory in a QEMU/KVM
virtual machine.  When initiating hot-unplug when most of the guest memory
is allocated, hot-unplug hangs partway through removal due to migration
failures.  The following message would be printed several times, and would
be printed again about every five seconds:

[   49.641309] migrating pfn b12f25 failed ret:7
[   49.641310] page: refcount:2 mapcount:0 mapping:0000000033bd8fe2 index:0x7f404d925 pfn:0xb12f25
[   49.641311] aops:swap_aops
[   49.641313] flags: 0x300000000030508(uptodate|active|owner_priv_1|reclaim|swapbacked|node=0|zone=3)
[   49.641314] raw: 0300000000030508 ffffed312c4bc908 ffffed312c4bc9c8 0000000000000000
[   49.641315] raw: 00000007f404d925 00000000000c823b 00000002ffffffff 0000000000000000
[   49.641315] page dumped because: migration failure

When debugging this, I found that these migration failures were due to
__migrate_folio() returning -EAGAIN for a small set of folios because the
expected reference count it calculates via folio_expected_ref_count() is
one less than the actual reference count of the folios.  Furthermore, all
of the affected folios were not anonymous, but had the PG_swapcache flag
set, inspiring this patch.  After applying this patch, the memory
hot-unplug behaves as expected.

I tested this on a machine running Ubuntu 24.04 with kernel version
6.8.0-90-generic and 64GB of memory.  The guest VM is managed by libvirt
and runs Ubuntu 24.04 with kernel version 6.18 (though the head of the
mm-unstable branch as a Dec 16, 2025 was also tested and behaves the same)
and 48GB of memory.  The libvirt XML definition for the VM can be found at
[1].  CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_MOVABLE is set in the guest
kernel so the hot-pluggable memory is automatically onlined.

Below are the steps to reproduce this behavior:

1) Define and start and virtual machine
  host$ virsh -c qemu:///system define ./test_vm.xml # test_vm.xml from [1]
  host$ virsh -c qemu:///system start test_vm

2) Setup swap in the guest
  guest$ sudo fallocate -l 32G /swapfile
  guest$ sudo chmod 0600 /swapfile
  guest$ sudo mkswap /swapfile
  guest$ sudo swapon /swapfile

3) Use alloc_data [2] to allocate most of the remaining guest memory
  guest$ ./alloc_data 45

4) In a separate guest terminal, monitor the amount of used memory
  guest$ watch -n1 free -h

5) When alloc_data has finished allocating, initiate the memory
hot-unplug using the provided xml file [3]
  host$ virsh -c qemu:///system detach-device test_vm ./remove.xml --live

After initiating the memory hot-unplug, you should see the amount of
available memory in the guest decrease, and the amount of used swap data
increase.  If everything works as expected, when all of the memory is
unplugged, there should be around 8.5-9GB of data in swap.  If the
unplugging is unsuccessful, the amount of used swap data will settle below
that.  If that happens, you should be able to see log messages in dmesg
similar to the one posted above.

Link: https://lkml.kernel.org/r/20251216200727.2360228-1-bijan311@gmail.com
Link: https://github.com/BijanT/linux_patch_files/blob/main/test_vm.xml [1]
Link: https://github.com/BijanT/linux_patch_files/blob/main/alloc_data.c [2]
Link: https://github.com/BijanT/linux_patch_files/blob/main/remove.xml [3]
Fixes: 86ebd50224c0 ("mm: add folio_expected_ref_count() for reference count calculation")
Signed-off-by: Bijan Tabatabai 
Acked-by: David Hildenbrand (Red Hat) 
Acked-by: Zi Yan 
Reviewed-by: Baolin Wang 
Cc: Liam Howlett 
Cc: Lorenzo Stoakes 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Shivank Garg 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Cc: Kairui Song 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mm: simplify folio_expected_ref_count()

2026-01-11T14:22:23+00:00

[ Upstream commit 78cb1a13c42a6d843e21389f74d1edb90ed07288 ]

Now that PAGE_MAPPING_MOVABLE is gone, we can simplify and rely on the
folio_test_anon() test only.

... but staring at the users, this function should never even have been
called on movable_ops pages. E.g.,
* __buffer_migrate_folio() does not make sense for them
* folio_migrate_mapping() does not make sense for them
* migrate_huge_page_move_mapping() does not make sense for them
* __migrate_folio() does not make sense for them
* ... and khugepaged should never stumble over them

Let's simply refuse typed pages (which includes slab) except hugetlb, and
WARN.

Link: https://lkml.kernel.org/r/20250704102524.326966-26-david@redhat.com
Signed-off-by: David Hildenbrand 
Reviewed-by: Zi Yan 
Reviewed-by: Lorenzo Stoakes 
Reviewed-by: Harry Yoo 
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: "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 
Signed-off-by: Andrew Morton 
Stable-dep-of: f183663901f2 ("mm: consider non-anon swap cache folios in folio_expected_ref_count()")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

mptcp: pm: ignore unknown endpoint flags

2026-01-11T14:22:22+00:00

[ Upstream commit 0ace3297a7301911e52d8195cb1006414897c859 ]

Before this patch, the kernel was saving any flags set by the userspace,
even unknown ones. This doesn't cause critical issues because the kernel
is only looking at specific ones. But on the other hand, endpoints dumps
could tell the userspace some recent flags seem to be supported on older
kernel versions.

Instead, ignore all unknown flags when parsing them. By doing that, the
userspace can continue to set unsupported flags, but it has a way to
verify what is supported by the kernel.

Note that it sounds better to continue accepting unsupported flags not
to change the behaviour, but also that eases things on the userspace
side by adding "optional" endpoint types only supported by newer kernel
versions without having to deal with the different kernel versions.

A note for the backports: there will be conflicts in mptcp.h on older
versions not having the mentioned flags, the new line should still be
added last, and the '5' needs to be adapted to have the same value as
the last entry.

Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-1-9e4781a6c1b8@kernel.org
Signed-off-by: Jakub Kicinski 
[ GENMASK(5, 0) => GENMASK(4, 0) + context ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

ALSA: wavefront: Use standard print API

2026-01-11T14:22:20+00:00

[ Upstream commit 8b4ac5429938dd5f1fbf2eea0687f08cbcccb6be ]

Use the standard print API with dev_*() instead of the old house-baked
one.  It gives better information and allows dynamically control of
debug prints.

Reviewed-by: Jaroslav Kysela 
Signed-off-by: Takashi Iwai 
Link: https://patch.msgid.link/20240807133452.9424-36-tiwai@suse.de
Stable-dep-of: 0c4a13ba8859 ("ALSA: wavefront: Fix integer overflow in sample size validation")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman