Tetsuo reported the following lockdep splat when the TSC synchronization
fails during CPU hotplug:

tsc: Marking TSC unstable due to check_tsc_sync_source failed

WARNING: inconsistent lock state
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
ffffffff8cfa1c78 (watchdog_lock){?.-.}-{2:2}, at: clocksource_watchdog+0x23/0x5a0
{IN-HARDIRQ-W} state was registered at:
_raw_spin_lock_irqsave+0x3f/0x60
clocksource_mark_unstable+0x1b/0x90
mark_tsc_unstable+0x41/0x50
check_tsc_sync_source+0x14f/0x180
sysvec_call_function_single+0x69/0x90

Possible unsafe locking scenario:
lock(watchdog_lock);
<Interrupt>
lock(watchdog_lock);

stack backtrace:
_raw_spin_lock+0x30/0x40
clocksource_watchdog+0x23/0x5a0
run_timer_softirq+0x2a/0x50
sysvec_apic_timer_interrupt+0x6e/0x90

The reason is the recent conversion of the TSC synchronization function
during CPU hotplug on the control CPU to a SMP function call. In case
that the synchronization with the upcoming CPU fails, the TSC has to be
marked unstable via clocksource_mark_unstable().

clocksource_mark_unstable() acquires 'watchdog_lock', but that lock is
taken with interrupts enabled in the watchdog timer callback to minimize
interrupt disabled time. That's obviously a possible deadlock scenario,

Before that change the synchronization function was invoked in thread
context so this could not happen.

As it is not crucical whether the unstable marking happens slightly
delayed, defer the call to a worker thread which avoids the lock context
problem.

Fixes: 9d349d47f0e3 ("x86/smpboot: Make TSC synchronization function call based")
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87zg064ceg.ffs@tglx

David and a few others reported that on certain newer systems some legacy
interrupts fail to work correctly.

Debugging revealed that the BIOS of these systems leaves the legacy PIC in
uninitialized state which makes the PIC detection fail and the kernel
switches to a dummy implementation.

Unfortunately this fallback causes quite some code to fail as it depends on
checks for the number of legacy PIC interrupts or the availability of the
real PIC.

In theory there is no reason to use the PIC on any modern system when
IO/APIC is available, but the dependencies on the related checks cannot be
resolved trivially and on short notice. This needs lots of analysis and
rework.

The PIC detection has been added to avoid quirky checks and force selection
of the dummy implementation all over the place, especially in VM guest
scenarios. So it's not an option to revert the relevant commit as that
would break a lot of other scenarios.

One solution would be to try to initialize the PIC on detection fail and
retry the detection, but that puts the burden on everything which does not
have a PIC.

Fortunately the ACPI/MADT table header has a flag field, which advertises
in bit 0 that the system is PCAT compatible, which means it has a legacy
8259 PIC.

Evaluate that bit and if set avoid the detection routine and keep the real
PIC installed, which then gets initialized (for nothing) and makes the rest
of the code with all the dependencies work again.

Fixes: e179f6914152 ("x86, irq, pic: Probe for legacy PIC and set legacy_pic appropriately")
Reported-by: David Lazar <dlazar@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: David Lazar <dlazar@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Cc: stable@vger.kernel.org
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218003
Link: https://lore.kernel.org/r/875y2u5s8g.ffs@tglx

For "reasons" Intel has code-named this CPU with a "_H" suffix.

[ dhansen: As usual, apply this and send it upstream quickly to
make it easier for anyone who is doing work that
consumes this. ]

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20231025202513.12358-1-tony.luck%40intel.com

Pull networking fixes from Jakub Kicinski:
"Including fixes from bluetooth, netfilter, WiFi.

Feels like an up-tick in regression fixes, mostly for older releases.
The hfsc fix, tcp_disconnect() and Intel WWAN fixes stand out as
fairly clear-cut user reported regressions. The mlx5 DMA bug was
causing strife for 390x folks. The fixes themselves are not
particularly scary, tho. No open investigations / outstanding reports
at the time of writing.

Current release - regressions:

- eth: mlx5: perform DMA operations in the right locations, make
devices usable on s390x, again

- sched: sch_hfsc: upgrade 'rt' to 'sc' when it becomes a inner
curve, previous fix of rejecting invalid config broke some scripts

- rfkill: reduce data->mtx scope in rfkill_fop_open, avoid deadlock

- revert "ethtool: Fix mod state of verbose no_mask bitset", needs
more work

Current release - new code bugs:

- tcp: fix listen() warning with v4-mapped-v6 address

Previous releases - regressions:

- tcp: allow tcp_disconnect() again when threads are waiting, it was
denied to plug a constant source of bugs but turns out .NET depends
on it

- eth: mlx5: fix double-free if buffer refill fails under OOM

- revert "net: wwan: iosm: enable runtime pm support for 7560", it's
causing regressions and the WWAN team at Intel disappeared

- tcp: tsq: relax tcp_small_queue_check() when rtx queue contains a
single skb, fix single-stream perf regression on some devices

Previous releases - always broken:

- Bluetooth:
- fix issues in legacy BR/EDR PIN code pairing
- correctly bounds check and pad HCI_MON_NEW_INDEX name

- netfilter:
- more fixes / follow ups for the large "commit protocol" rework,
which went in as a fix to 6.5
- fix null-derefs on netlink attrs which user may not pass in

- tcp: fix excessive TLP and RACK timeouts from HZ rounding (bless
Debian for keeping HZ=250 alive)

- net: more strict VIRTIO_NET_HDR_GSO_UDP_L4 validation, prevent
letting frankenstein UDP super-frames from getting into the stack

- net: fix interface altnames when ifc moves to a new namespace

- eth: qed: fix the size of the RX buffers

- mptcp: avoid sending RST when closing the initial subflow"

* tag 'net-6.6-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (94 commits)
Revert "ethtool: Fix mod state of verbose no_mask bitset"
selftests: mptcp: join: no RST when rm subflow/addr
mptcp: avoid sending RST when closing the initial subflow
mptcp: more conservative check for zero probes
tcp: check mptcp-level constraints for backlog coalescing
selftests: mptcp: join: correctly check for no RST
net: ti: icssg-prueth: Fix r30 CMDs bitmasks
selftests: net: add very basic test for netdev names and namespaces
net: move altnames together with the netdevice
net: avoid UAF on deleted altname
net: check for altname conflicts when changing netdev's netns
net: fix ifname in netlink ntf during netns move
net: ethernet: ti: Fix mixed module-builtin object
net: phy: bcm7xxx: Add missing 16nm EPHY statistics
ipv4: fib: annotate races around nh->nh_saddr_genid and nh->nh_saddr
tcp_bpf: properly release resources on error paths
net/sched: sch_hfsc: upgrade 'rt' to 'sc' when it becomes a inner curve
net: mdio-mux: fix C45 access returning -EIO after API change
tcp: tsq: relax tcp_small_queue_check() when rtx queue contains a single skb
octeon_ep: update BQL sent bytes before ringing doorbell
...

Pull LoongArch fixes from Huacai ChenL
"Fix 4-level pagetable building, disable WUC for pgprot_writecombine()
like ioremap_wc(), use correct annotation for exception handlers, and
a trivial cleanup"

* tag 'loongarch-fixes-6.6-3' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
LoongArch: Disable WUC for pgprot_writecombine() like ioremap_wc()
LoongArch: Replace kmap_atomic() with kmap_local_page() in copy_user_highpage()
LoongArch: Export symbol invalid_pud_table for modules building
LoongArch: Use SYM_CODE_* to annotate exception handlers

This reverts commit 108a36d07c01edbc5942d27c92494d1c6e4d45a0.

It was reported that this fix breaks the possibility to remove existing WoL
flags. For example:
~$ ethtool lan2
...
Supports Wake-on: pg
Wake-on: d
...
~$ ethtool -s lan2 wol gp
~$ ethtool lan2
...
Wake-on: pg
...
~$ ethtool -s lan2 wol d
~$ ethtool lan2
...
Wake-on: pg
...

This worked correctly before this commit because we were always updating
a zero bitmap (since commit 6699170376ab ("ethtool: fix application of
verbose no_mask bitset"), that is) so that the rest was left zero
naturally. But now the 1->0 change (old_val is true, bit not present in
netlink nest) no longer works.

Reported-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reported-by: Michal Kubecek <mkubecek@suse.cz>
Closes: https://lore.kernel.org/netdev/20231019095140.l6fffnszraeb6iiw@lion.mk-sys.cz/
Cc: stable@vger.kernel.org
Fixes: 108a36d07c01 ("ethtool: Fix mod state of verbose no_mask bitset")
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Reviewed-by: Michal Kubecek <mkubecek@suse.cz>
Link: https://lore.kernel.org/r/20231019-feature_ptp_bitset_fix-v1-1-70f3c429a221@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Pull slab fix from Vlastimil Babka:

- stable fix to prevent kernel warnings with KASAN_HW_TAGS on arm64
due to improperly resolved kmalloc alignment restrictions (Catalin
Marinas)

* tag 'slab-fixes-for-6.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
mm: slab: Do not create kmalloc caches smaller than arch_slab_minalign()

Currently the code disables WUC only disables it for ioremap_wc(), which
is only used when mapping writecombine pages like ioremap() (mapped to
the kernel space). But for VRAM mapped in TTM/GEM, it is mapped with a
crafted pgprot by the pgprot_writecombine() function, in which case WUC
isn't disabled now.

Disable WUC for pgprot_writecombine() (fallback to SUC) if needed, like
ioremap_wc().

This improves the AMDGPU driver's stability (solves some misrendering)
on Loongson-3A5000/3A6000 machines.

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Mat Martineau says:

====================
mptcp: Fixes for v6.6

Patch 1 corrects the logic for MP_JOIN tests where 0 RSTs are expected.

Patch 2 ensures MPTCP packets are not incorrectly coalesced in the TCP
backlog queue.

Patch 3 avoids a zero-window probe and associated WARN_ON_ONCE() in an
expected MPTCP reinjection scenario.

Patches 4 & 5 allow an initial MPTCP subflow to be closed cleanly
instead of always sending RST. Associated selftest is updated.
====================

Link: https://lore.kernel.org/r/20231018-send-net-20231018-v1-0-17ecb002e41d@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Pull seccomp fix from Kees Cook:

- Fix seccomp_unotify perf benchmark for 32-bit (Jiri Slaby)

* tag 'seccomp-v6.6-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
perf/benchmark: fix seccomp_unotify benchmark for 32-bit

Commit b035f5a6d852 ("mm: slab: reduce the kmalloc() minimum alignment
if DMA bouncing possible") allows architectures with non-coherent DMA to
define a small ARCH_KMALLOC_MINALIGN (e.g. sizeof(unsigned long long))
and this has been enabled on arm64. With KASAN_HW_TAGS enabled, however,
ARCH_SLAB_MINALIGN becomes 16 on arm64 (arch_slab_minalign() dynamically
selects it since commit d949a8155d13 ("mm: make minimum slab alignment a
runtime property")). This can lead to a situation where kmalloc-8 caches
are attempted to be created with a kmem_caches.size aligned to 16. When
the cache is mergeable, it can lead to kernel warnings like:

sysfs: cannot create duplicate filename '/kernel/slab/:d-0000016'
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.6.0-rc1-00001-gda98843cd306-dirty #5
Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
Call trace:
dump_backtrace+0x90/0xe8
show_stack+0x18/0x24
dump_stack_lvl+0x48/0x60
dump_stack+0x18/0x24
sysfs_warn_dup+0x64/0x80
sysfs_create_dir_ns+0xe8/0x108
kobject_add_internal+0x98/0x264
kobject_init_and_add+0x8c/0xd8
sysfs_slab_add+0x12c/0x248
slab_sysfs_init+0x98/0x14c
do_one_initcall+0x6c/0x1b0
kernel_init_freeable+0x1c0/0x288
kernel_init+0x24/0x1e0
ret_from_fork+0x10/0x20
kobject: kobject_add_internal failed for :d-0000016 with -EEXIST, don't try to register things with the same name in the same directory.
SLUB: Unable to add boot slab dma-kmalloc-8 to sysfs

Limit the __kmalloc_minalign() return value (used to create the
kmalloc-* caches) to arch_slab_minalign() so that kmalloc-8 caches are
skipped when KASAN_HW_TAGS is enabled (both config and runtime).

Reported-by: Mark Rutland <mark.rutland@arm.com>
Fixes: b035f5a6d852 ("mm: slab: reduce the kmalloc() minimum alignment if DMA bouncing possible")
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: stable@vger.kernel.org # 6.5.x
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

Replace kmap_atomic()/kunmap_atomic() calls with kmap_local_page()/
kunmap_local() in copy_user_highpage() which can be invoked from both
preemptible and atomic context [1].

[1] https://lore.kernel.org/all/20201029222652.302358281@linutronix.de/

Suggested-by: Deepak R Varma <drv@mailo.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

The bitmasks for EMAC_PORT_DISABLE and EMAC_PORT_FORWARD r30 commands are
wrong in the driver.

Update the bitmasks of these commands to the correct ones as used by the
ICSSG firmware. These bitmasks are backwards compatible and work with
any ICSSG firmware version.

Fixes: e9b4ece7d74b ("net: ti: icssg-prueth: Add Firmware config and classification APIs.")
Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20231018150715.3085380-1-danishanwar@ti.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Recently, we noticed that some RST were wrongly generated when removing
the initial subflow.

This patch makes sure RST are not sent when removing any subflows or any
addresses.

Fixes: c2b2ae3925b6 ("mptcp: handle correctly disconnect() failures")
Cc: stable@vger.kernel.org
Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Matthieu Baerts <matttbe@kernel.org>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20231018-send-net-20231018-v1-5-17ecb002e41d@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Pull vfs fix from Christian Brauner:
"An openat() call from io_uring triggering an audit call can apparently
cause the refcount of struct filename to be incremented from multiple
threads concurrently during async execution, triggering a refcount
underflow and hitting a BUG_ON(). That bug has been lurking around
since at least v5.16 apparently.

Switch to an atomic counter to fix that. The underflow check is
downgraded from a BUG_ON() to a WARN_ON_ONCE() but we could easily
remove that check altogether tbh"

* tag 'v6.6-rc7.vfs.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
audit,io_uring: io_uring openat triggers audit reference count underflow