This was attempted by using the dev_name in the slab cache name, but as
Omar Sandoval pointed out, that can be an arbitrary string, eg something
like "/dev/root".  Which in turn trips verify_dirent_name(), which fails
if a filename contains a slash.

So just make it use a sequence counter, and make it an atomic_t to avoid
any possible races or locking issues.
Reported-and-tested-by: Omar Sandoval <osandov@fb.com>
Link: https://lore.kernel.org/all/ZxafcO8KWMlXaeWE@telecaster.dhcp.thefacebook.com/
Fixes: 79efebae ("9p: Avoid creating multiple slab caches with the same name")
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Thorsten Leemhuis <regressions@leemhuis.info>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull kvm fixes from Paolo Bonzini:
 "ARM64:

   - Fix the guest view of the ID registers, making the relevant fields
     writable from userspace (affecting ID_AA64DFR0_EL1 and
     ID_AA64PFR1_EL1)

   - Correcly expose S1PIE to guests, fixing a regression introduced in
     6.12-rc1 with the S1POE support

   - Fix the recycling of stage-2 shadow MMUs by tracking the context
     (are we allowed to block or not) as well as the recycling state

   - Address a couple of issues with the vgic when userspace
     misconfigures the emulation, resulting in various splats. Headaches
     courtesy of our Syzkaller friends

   - Stop wasting space in the HYP idmap, as we are dangerously close to
     the 4kB limit, and this has already exploded in -next

   - Fix another race in vgic_init()

   - Fix a UBSAN error when faking the cache topology with MTE enabled

  RISCV:

   - RISCV: KVM: use raw_spinlock for critical section in imsic

  x86:

   - A bandaid for lack of XCR0 setup in selftests, which causes trouble
     if the compiler is configured to have x86-64-v3 (with AVX) as the
     default ISA. Proper XCR0 setup will come in the next merge window.

   - Fix an issue where KVM would not ignore low bits of the nested CR3
     and potentially leak up to 31 bytes out of the guest memory's
     bounds

   - Fix case in which an out-of-date cached value for the segments
     could by returned by KVM_GET_SREGS.

   - More cleanups for KVM_X86_QUIRK_SLOT_ZAP_ALL

   - Override MTRR state for KVM confidential guests, making it WB by
     default as is already the case for Hyper-V guests.

  Generic:

   - Remove a couple of unused functions"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (27 commits)
  RISCV: KVM: use raw_spinlock for critical section in imsic
  KVM: selftests: Fix out-of-bounds reads in CPUID test's array lookups
  KVM: selftests: x86: Avoid using SSE/AVX instructions
  KVM: nSVM: Ignore nCR3[4:0] when loading PDPTEs from memory
  KVM: VMX: reset the segment cache after segment init in vmx_vcpu_reset()
  KVM: x86: Clean up documentation for KVM_X86_QUIRK_SLOT_ZAP_ALL
  KVM: x86/mmu: Add lockdep assert to enforce safe usage of kvm_unmap_gfn_range()
  KVM: x86/mmu: Zap only SPs that shadow gPTEs when deleting memslot
  x86/kvm: Override default caching mode for SEV-SNP and TDX
  KVM: Remove unused kvm_vcpu_gfn_to_pfn_atomic
  KVM: Remove unused kvm_vcpu_gfn_to_pfn
  KVM: arm64: Ensure vgic_ready() is ordered against MMIO registration
  KVM: arm64: vgic: Don't check for vgic_ready() when setting NR_IRQS
  KVM: arm64: Fix shift-out-of-bounds bug
  KVM: arm64: Shave a few bytes from the EL2 idmap code
  KVM: arm64: Don't eagerly teardown the vgic on init error
  KVM: arm64: Expose S1PIE to guests
  KVM: arm64: nv: Clarify safety of allowing TLBI unmaps to reschedule
  KVM: arm64: nv: Punt stage-2 recycling to a vCPU request
  KVM: arm64: nv: Do not block when unmapping stage-2 if disallowed
  ...

Merge tag 'probes-fixes-v6.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull uprobe fix from Masami Hiramatsu:

 - uprobe: avoid out-of-bounds memory access of fetching args

   Uprobe trace events can cause out-of-bounds memory access when
   fetching user-space data which is bigger than one page, because it
   does not check the local CPU buffer size when reading the data. This
   checks the read data size and cut it down to the local CPU buffer
   size.

* tag 'probes-fixes-v6.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  uprobe: avoid out-of-bounds memory access of fetching args

Pull vfs fixes from Christian Brauner:
 "afs:
   - Fix a lock recursion in afs_wake_up_async_call() on ->notify_lock

 netfs:
   - Drop the references to a folio immediately after the folio has been
     extracted to prevent races with future I/O collection

   - Fix a documenation build error

   - Downgrade the i_rwsem for buffered writes to fix a cifs reported
     performance regression when switching to netfslib

  vfs:
   - Explicitly return -E2BIG from openat2() if the specified size is
     unexpectedly large. This aligns openat2() with other extensible
     struct based system calls

   - When copying a mount namespace ensure that we only try to remove
     the new copy from the mount namespace rbtree if it has already been
     added to it

  nilfs:
   - Clear the buffer delay flag when clearing the buffer state clags
     when a buffer head is discarded to prevent a kernel OOPs

  ocfs2:
   - Fix an unitialized value warning in ocfs2_setattr()

  proc:
   - Fix a kernel doc warning"

* tag 'vfs-6.12-rc5.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  proc: Fix W=1 build kernel-doc warning
  afs: Fix lock recursion
  fs: Fix uninitialized value issue in from_kuid and from_kgid
  fs: don't try and remove empty rbtree node
  netfs: Downgrade i_rwsem for a buffered write
  nilfs2: fix kernel bug due to missing clearing of buffer delay flag
  openat2: explicitly return -E2BIG for (usize > PAGE_SIZE)
  netfs: fix documentation build error
  netfs: In readahead, put the folio refs as soon extracted

Pull crypto fix from Herbert Xu:
 "Fix a regression in mpi that broke RSA"

* tag 'v6.12-p4' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: lib/mpi - Fix an "Uninitialized scalar variable" issue

Uprobe needs to fetch args into a percpu buffer, and then copy to ring
buffer to avoid non-atomic context problem.

Sometimes user-space strings, arrays can be very large, but the size of
percpu buffer is only page size. And store_trace_args() won't check
whether these data exceeds a single page or not, caused out-of-bounds
memory access.

It could be reproduced by following steps:
1. build kernel with CONFIG_KASAN enabled
2. save follow program as test.c

```
\#include <stdio.h>
\#include <stdlib.h>
\#include <string.h>

// If string length large than MAX_STRING_SIZE, the fetch_store_strlen()
// will return 0, cause __get_data_size() return shorter size, and
// store_trace_args() will not trigger out-of-bounds access.
// So make string length less than 4096.
\#define STRLEN 4093

void generate_string(char *str, int n)
{
    int i;
    for (i = 0; i < n; ++i)
    {
        char c = i % 26 + 'a';
        str[i] = c;
    }
    str[n-1] = '\0';
}

void print_string(char *str)
{
    printf("%s\n", str);
}

int main()
{
    char tmp[STRLEN];

    generate_string(tmp, STRLEN);
    print_string(tmp);

    return 0;
}
```
3. compile program
`gcc -o test test.c`

4. get the offset of `print_string()`
```
objdump -t test | grep -w print_string
0000000000401199 g     F .text  000000000000001b              print_string
```

5. configure uprobe with offset 0x1199
```
off=0x1199

cd /sys/kernel/debug/tracing/
echo "p /root/test:${off} arg1=+0(%di):ustring arg2=\$comm arg3=+0(%di):ustring"
 > uprobe_events
echo 1 > events/uprobes/enable
echo 1 > tracing_on
```

6. run `test`, and kasan will report error.
==================================================================
BUG: KASAN: use-after-free in strncpy_from_user+0x1d6/0x1f0
Write of size 8 at addr ffff88812311c004 by task test/499CPU: 0 UID: 0 PID: 499 Comm: test Not tainted 6.12.0-rc3+ #18
Hardware name: Red Hat KVM, BIOS 1.16.0-4.al8 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x55/0x70
 print_address_description.constprop.0+0x27/0x310
 kasan_report+0x10f/0x120
 ? strncpy_from_user+0x1d6/0x1f0
 strncpy_from_user+0x1d6/0x1f0
 ? rmqueue.constprop.0+0x70d/0x2ad0
 process_fetch_insn+0xb26/0x1470
 ? __pfx_process_fetch_insn+0x10/0x10
 ? _raw_spin_lock+0x85/0xe0
 ? __pfx__raw_spin_lock+0x10/0x10
 ? __pte_offset_map+0x1f/0x2d0
 ? unwind_next_frame+0xc5f/0x1f80
 ? arch_stack_walk+0x68/0xf0
 ? is_bpf_text_address+0x23/0x30
 ? kernel_text_address.part.0+0xbb/0xd0
 ? __kernel_text_address+0x66/0xb0
 ? unwind_get_return_address+0x5e/0xa0
 ? __pfx_stack_trace_consume_entry+0x10/0x10
 ? arch_stack_walk+0xa2/0xf0
 ? _raw_spin_lock_irqsave+0x8b/0xf0
 ? __pfx__raw_spin_lock_irqsave+0x10/0x10
 ? depot_alloc_stack+0x4c/0x1f0
 ? _raw_spin_unlock_irqrestore+0xe/0x30
 ? stack_depot_save_flags+0x35d/0x4f0
 ? kasan_save_stack+0x34/0x50
 ? kasan_save_stack+0x24/0x50
 ? mutex_lock+0x91/0xe0
 ? __pfx_mutex_lock+0x10/0x10
 prepare_uprobe_buffer.part.0+0x2cd/0x500
 uprobe_dispatcher+0x2c3/0x6a0
 ? __pfx_uprobe_dispatcher+0x10/0x10
 ? __kasan_slab_alloc+0x4d/0x90
 handler_chain+0xdd/0x3e0
 handle_swbp+0x26e/0x3d0
 ? __pfx_handle_swbp+0x10/0x10
 ? uprobe_pre_sstep_notifier+0x151/0x1b0
 irqentry_exit_to_user_mode+0xe2/0x1b0
 asm_exc_int3+0x39/0x40
RIP: 0033:0x401199
Code: 01 c2 0f b6 45 fb 88 02 83 45 fc 01 8b 45 fc 3b 45 e4 7c b7 8b 45 e4 48 98 48 8d 50 ff 48 8b 45 e8 48 01 d0 ce
RSP: 002b:00007ffdf00576a8 EFLAGS: 00000206
RAX: 00007ffdf00576b0 RBX: 0000000000000000 RCX: 0000000000000ff2
RDX: 0000000000000ffc RSI: 0000000000000ffd RDI: 00007ffdf00576b0
RBP: 00007ffdf00586b0 R08: 00007feb2f9c0d20 R09: 00007feb2f9c0d20
R10: 0000000000000001 R11: 0000000000000202 R12: 0000000000401040
R13: 00007ffdf0058780 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

This commit enforces the buffer's maxlen less than a page-size to avoid
store_trace_args() out-of-memory access.

Link: https://lore.kernel.org/all/20241015060148.1108331-1-mqaio@linux.alibaba.com/

Fixes: dcad1a20 ("tracing/uprobes: Fetch args before reserving a ring buffer")
Signed-off-by: Qiao Ma <mqaio@linux.alibaba.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Pull bluetooth fixes from Luiz Augusto Von Dentz:

 - ISO: Fix multiple init when debugfs is disabled

 - Call iso_exit() on module unload

 - Remove debugfs directory on module init failure

 - btusb: Fix not being able to reconnect after suspend

 - btusb: Fix regression with fake CSR controllers 0a12:0001

 - bnep: fix wild-memory-access in proto_unregister

Note: normally the bluetooth fixes go through the networking tree, but
this missed the weekly merge, and two of the commits fix regressions
that have caused a fair amount of noise and have now hit stable too:

  https://lore.kernel.org/all/4e1977ca-6166-4891-965e-34a6f319035f@leemhuis.info/

So I'm pulling it directly just to expedite things and not miss yet
another -rc release. This is not meant to become a new pattern.

* tag 'for-net-2024-10-16' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth:
  Bluetooth: btusb: Fix regression with fake CSR controllers 0a12:0001
  Bluetooth: bnep: fix wild-memory-access in proto_unregister
  Bluetooth: btusb: Fix not being able to reconnect after suspend
  Bluetooth: Remove debugfs directory on module init failure
  Bluetooth: Call iso_exit() on module unload
  Bluetooth: ISO: Fix multiple init when debugfs is disabled

Pull pin control fixes from Linus Walleij:
 "Mostly error path fixes, but one pretty serious interrupt problem in
  the Ocelot driver as well:

   - Fix two error paths and a missing semicolon in the Intel driver

   - Add a missing ACPI ID for the Intel Panther Lake

   - Check return value of devm_kasprintf() in the Apple and STM32
     drivers

   - Add a missing mutex_destroy() in the aw9523 driver

   - Fix a double free in cv1800_pctrl_dt_node_to_map() in the Sophgo
     driver

   - Fix a double free in ma35_pinctrl_dt_node_to_map_func() in the
     Nuvoton driver

   - Fix a bug in the Ocelot interrupt handler making the system hang"

* tag 'pinctrl-v6.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  pinctrl: ocelot: fix system hang on level based interrupts
  pinctrl: nuvoton: fix a double free in ma35_pinctrl_dt_node_to_map_func()
  pinctrl: sophgo: fix double free in cv1800_pctrl_dt_node_to_map()
  pinctrl: intel: platform: Add Panther Lake to the list of supported
  pinctrl: aw9523: add missing mutex_destroy
  pinctrl: stm32: check devm_kasprintf() returned value
  pinctrl: apple: check devm_kasprintf() returned value
  pinctrl: intel: platform: use semicolon instead of comma in ncommunities assignment
  pinctrl: intel: platform: fix error path in device_for_each_child_node()

Pull misc driver fixes from Greg KH:
 "Here are a number of small char/misc/iio driver fixes for 6.12-rc4:

   - loads of small iio driver fixes for reported problems

   - parport driver out-of-bounds fix

   - Kconfig description and MAINTAINERS file updates

  All of these, except for the Kconfig and MAINTAINERS file updates have
  been in linux-next all week. Those other two are just documentation
  changes and will have no runtime issues and were merged on Friday"

* tag 'char-misc-6.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (39 commits)
  misc: rtsx: list supported models in Kconfig help
  MAINTAINERS: Remove some entries due to various compliance requirements.
  misc: microchip: pci1xxxx: add support for NVMEM_DEVID_AUTO for OTP device
  misc: microchip: pci1xxxx: add support for NVMEM_DEVID_AUTO for EEPROM device
  parport: Proper fix for array out-of-bounds access
  iio: frequency: admv4420: fix missing select REMAP_SPI in Kconfig
  iio: frequency: {admv4420,adrf6780}: format Kconfig entries
  iio: adc: ad4695: Add missing Kconfig select
  iio: adc: ti-ads8688: add missing select IIO_(TRIGGERED_)BUFFER in Kconfig
  iio: hid-sensors: Fix an error handling path in _hid_sensor_set_report_latency()
  iioc: dac: ltc2664: Fix span variable usage in ltc2664_channel_config()
  iio: dac: stm32-dac-core: add missing select REGMAP_MMIO in Kconfig
  iio: dac: ltc1660: add missing select REGMAP_SPI in Kconfig
  iio: dac: ad5770r: add missing select REGMAP_SPI in Kconfig
  iio: amplifiers: ada4250: add missing select REGMAP_SPI in Kconfig
  iio: frequency: adf4377: add missing select REMAP_SPI in Kconfig
  iio: resolver: ad2s1210: add missing select (TRIGGERED_)BUFFER in Kconfig
  iio: resolver: ad2s1210 add missing select REGMAP in Kconfig
  iio: proximity: mb1232: add missing select IIO_(TRIGGERED_)BUFFER in Kconfig
  iio: pressure: bm1390: add missing select IIO_(TRIGGERED_)BUFFER in Kconfig
  ...

Pull tty/serial driver fixes from Greg KH:
 "Here are some small tty and serial driver fixes for 6.12-rc4:

   - qcom-geni serial driver fixes, wow what a mess of a UART chip that
     thing is...

   - vt infoleak fix for odd font sizes

   - imx serial driver bugfix

   - yet-another n_gsm ldisc bugfix, slowly chipping down the issues in
     that piece of code

  All of these have been in linux-next for over a week with no reported
  issues"

* tag 'tty-6.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: qcom-geni: rename suspend functions
  serial: qcom-geni: drop unused receive parameter
  serial: qcom-geni: drop flip buffer WARN()
  serial: qcom-geni: fix rx cancel dma status bit
  serial: qcom-geni: fix receiver enable
  serial: qcom-geni: fix dma rx cancellation
  serial: qcom-geni: fix shutdown race
  serial: qcom-geni: revert broken hibernation support
  serial: qcom-geni: fix polled console initialisation
  serial: imx: Update mctrl old_status on RTSD interrupt
  tty: n_gsm: Fix use-after-free in gsm_cleanup_mux
  vt: prevent kernel-infoleak in con_font_get()

Pull USB driver fixes from Greg KH:
 "Here are some small USB driver fixes and new device ids for 6.12-rc4:

   - xhci driver fixes for a number of reported issues

   - new usb-serial driver ids

   - dwc3 driver fixes for reported problems.

   - usb gadget driver fixes for reported problems

   - typec driver fixes

   - MAINTAINER file updates

  All of these have been in linux-next this week with no reported issues"

* tag 'usb-6.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: serial: option: add Telit FN920C04 MBIM compositions
  USB: serial: option: add support for Quectel EG916Q-GL
  xhci: dbc: honor usb transfer size boundaries.
  usb: xhci: Fix handling errors mid TD followed by other errors
  xhci: Mitigate failed set dequeue pointer commands
  xhci: Fix incorrect stream context type macro
  USB: gadget: dummy-hcd: Fix "task hung" problem
  usb: gadget: f_uac2: fix return value for UAC2_ATTRIBUTE_STRING store
  usb: dwc3: core: Fix system suspend on TI AM62 platforms
  xhci: tegra: fix checked USB2 port number
  usb: dwc3: Wait for EndXfer completion before restoring GUSB2PHYCFG
  usb: typec: qcom-pmic-typec: fix sink status being overwritten with RP_DEF
  usb: typec: altmode should keep reference to parent
  MAINTAINERS: usb: raw-gadget: add bug tracker link
  MAINTAINERS: Add an entry for the LJCA drivers

Pull x86 fixes from Borislav Petkov:

 - Explicitly disable the TSC deadline timer when going idle to address
   some CPU errata in that area

 - Do not apply the Zenbleed fix on anything else except AMD Zen2 on the
   late microcode loading path

 - Clear CPU buffers later in the NMI exit path on 32-bit to avoid
   register clearing while they still contain sensitive data, for the
   RDFS mitigation

 - Do not clobber EFLAGS.ZF with VERW on the opportunistic SYSRET exit
   path on 32-bit

 - Fix parsing issues of memory bandwidth specification in sysfs for
   resctrl's memory bandwidth allocation feature

 - Other small cleanups and improvements

* tag 'x86_urgent_for_v6.12_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/apic: Always explicitly disarm TSC-deadline timer
  x86/CPU/AMD: Only apply Zenbleed fix for Zen2 during late microcode load
  x86/bugs: Use code segment selector for VERW operand
  x86/entry_32: Clear CPU buffers after register restore in NMI return
  x86/entry_32: Do not clobber user EFLAGS.ZF
  x86/resctrl: Annotate get_mem_config() functions as __init
  x86/resctrl: Avoid overflow in MB settings in bw_validate()
  x86/amd_nb: Add new PCI ID for AMD family 1Ah model 20h

Pull irq fixes from Borislav Petkov:

 - Fix a case for sifive-plic where an interrupt gets disabled *and*
   masked and remains masked when it gets reenabled later

 - Plug a small race in GIC-v4 where userspace can force an affinity
   change of a virtual CPU (vPE) in its unmapping path

 - Do not mix the two sets of ocelot irqchip's registers in the mask
   calculation of the main interrupt sticky register

- Other smaller fixlets and cleanups

* tag 'irq_urgent_for_v6.12_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/renesas-rzg2l: Fix missing put_device
  irqchip/riscv-intc: Fix SMP=n boot with ACPI
  irqchip/sifive-plic: Unmask interrupt in plic_irq_enable()
  irqchip/gic-v4: Don't allow a VMOVP on a dying VPE
  irqchip/sifive-plic: Return error code on failure
  irqchip/riscv-imsic: Fix output text of base address
  irqchip/ocelot: Comment sticky register clearing code
  irqchip/ocelot: Fix trigger register address
  irqchip: Remove obsolete config ARM_GIC_V3_ITS_PCI

Pull scheduling fixes from Borislav Petkov:

 - Add PREEMPT_RT maintainers

 - Fix another aspect of delayed dequeued tasks wrt determining their
   state, i.e., whether they're runnable or blocked

 - Handle delayed dequeued tasks and their migration wrt PSI properly

 - Fix the situation where a delayed dequeue task gets enqueued into a
   new class, which should not happen

 - Fix a case where memory allocation would happen while the runqueue
   lock is held, which is a no-no

 - Do not over-schedule when tasks with shorter slices preempt the
   currently running task

 - Make sure delayed to deque entities are properly handled before
   unthrottling

 - Other smaller cleanups and improvements

* tag 'sched_urgent_for_v6.12_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Add an entry for PREEMPT_RT.
  sched/fair: Fix external p->on_rq users
  sched/psi: Fix mistaken CPU pressure indication after corrupted task state bug
  sched/core: Dequeue PSI signals for blocked tasks that are delayed
  sched: Fix delayed_dequeue vs switched_from_fair()
  sched/core: Disable page allocation in task_tick_mm_cid()
  sched/deadline: Use hrtick_enabled_dl() before start_hrtick_dl()
  sched/eevdf: Fix wakeup-preempt by checking cfs_rq->nr_running
  sched: Fix sched_delayed vs cfs_bandwidth

Pull xen fix from Juergen Gross:
 "A single fix for a build failure introduced this merge window"

* tag 'for-linus-6.12a-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: Remove dependency between pciback and privcmd

Pull dma-mapping fix from Christoph Hellwig:
 "Just another small tracing fix from Sean"

* tag 'dma-mapping-6.12-2024-10-20' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: fix tracing dma_alloc/free with vmalloc'd memory

Merge tag 'kvmarm-fixes-6.12-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.12, take #3

- Stop wasting space in the HYP idmap, as we are dangerously close
  to the 4kB limit, and this has already exploded in -next

- Fix another race in vgic_init()

- Fix a UBSAN error when faking the cache topology with MTE
  enabled

Merge tag 'kvmarm-fixes-6.12-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.12, take #2

- Fix the guest view of the ID registers, making the relevant fields
  writable from userspace (affecting ID_AA64DFR0_EL1 and ID_AA64PFR1_EL1)

- Correcly expose S1PIE to guests, fixing a regression introduced
  in 6.12-rc1 with the S1POE support

- Fix the recycling of stage-2 shadow MMUs by tracking the context
  (are we allowed to block or not) as well as the recycling state

- Address a couple of issues with the vgic when userspace misconfigures
  the emulation, resulting in various splats. Headaches courtesy
  of our Syzkaller friends

For the external interrupt updating procedure in imsic, there was a
spinlock to protect it already. But since it should not be preempted in
any cases, we should turn to use raw_spinlock to prevent any preemption
in case PREEMPT_RT was enabled.
Signed-off-by: Cyan Yang <cyan.yang@sifive.com>
Reviewed-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Message-ID: <20240919160126.44487-1-cyan.yang@sifive.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When looking for a "mangled", i.e. dynamic, CPUID entry, terminate the
walk based on the number of array _entries_, not the size in bytes of
the array.  Iterating based on the total size of the array can result in
false passes, e.g. if the random data beyond the array happens to match
a CPUID entry's function and index.

Fixes: fb18d053 ("selftest: kvm: x86: test KVM_GET_CPUID2 and guest visible CPUIDs against KVM_GET_SUPPORTED_CPUID")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-ID: <20241003234337.273364-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Some distros switched gcc to '-march=x86-64-v3' by default and while it's
hard to find a CPU which doesn't support it today, many KVM selftests fail
with

  ==== Test Assertion Failure ====
    lib/x86_64/processor.c:570: Unhandled exception in guest
    pid=72747 tid=72747 errno=4 - Interrupted system call
    Unhandled exception '0x6' at guest RIP '0x4104f7'

The failure is easy to reproduce elsewhere with

   $ make clean && CFLAGS='-march=x86-64-v3' make -j && ./x86_64/kvm_pv_test

The root cause of the problem seems to be that with '-march=x86-64-v3' GCC
uses AVX* instructions (VMOVQ in the example above) and without prior
XSETBV() in the guest this results in #UD. It is certainly possible to add
it there, e.g. the following saves the day as well:
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-ID: <20240920154422.2890096-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Ignore nCR3[4:0] when loading PDPTEs from memory for nested SVM, as bits
4:0 of CR3 are ignored when PAE paging is used, and thus VMRUN doesn't
enforce 32-byte alignment of nCR3.

In the absolute worst case scenario, failure to ignore bits 4:0 can result
in an out-of-bounds read, e.g. if the target page is at the end of a
memslot, and the VMM isn't using guard pages.

Per the APM:

  The CR3 register points to the base address of the page-directory-pointer
  table. The page-directory-pointer table is aligned on a 32-byte boundary,
  with the low 5 address bits 4:0 assumed to be 0.

And the SDM's much more explicit:

  4:0    Ignored

Note, KVM gets this right when loading PDPTRs, it's only the nSVM flow
that is broken.

Fixes: e4e517b4 ("KVM: MMU: Do not unconditionally read PDPTE from guest memory")
Reported-by: Kirk Swidowski <swidowski@google.com>
Cc: Andy Nguyen <theflow@google.com>
Cc: 3pvd <3pvd@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20241009140838.1036226-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Reset the segment cache after segment initialization in vmx_vcpu_reset()
to harden KVM against caching stale/uninitialized data.  Without the
recent fix to bypass the cache in kvm_arch_vcpu_put(), the following
scenario is possible:

 - vCPU is just created, and the vCPU thread is preempted before
   SS.AR_BYTES is written in vmx_vcpu_reset().

 - When scheduling out the vCPU task, kvm_arch_vcpu_in_kernel() =>
   vmx_get_cpl() reads and caches '0' for SS.AR_BYTES.

 - vmx_vcpu_reset() => seg_setup() configures SS.AR_BYTES, but doesn't
   invoke vmx_segment_cache_clear() to invalidate the cache.

As a result, KVM retains a stale value in the cache, which can be read,
e.g. via KVM_GET_SREGS.  Usually this is not a problem because the VMX
segment cache is reset on each VM-Exit, but if the userspace VMM (e.g KVM
selftests) reads and writes system registers just after the vCPU was
created, _without_ modifying SS.AR_BYTES, userspace will write back the
stale '0' value and ultimately will trigger a VM-Entry failure due to
incorrect SS segment type.

Invalidating the cache after writing the VMCS doesn't address the general
issue of cache accesses from IRQ context being unsafe, but it does prevent
KVM from clobbering the VMCS, i.e. mitigates the harm done _if_ KVM has a
bug that results in an unsafe cache access.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Fixes: 2fb92db1 ("KVM: VMX: Cache vmcs segment fields")
[sean: rework changelog to account for previous patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20241009175002.1118178-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Massage the documentation for KVM_X86_QUIRK_SLOT_ZAP_ALL to call out that
it applies to moved memslots as well as deleted memslots, to avoid KVM's
"fast zap" terminology (which has no meaning for userspace), and to reword
the documented targeted zap behavior to specifically say that KVM _may_
zap a subset of all SPTEs.  As evidenced by the fix to zap non-leafs SPTEs
with gPTEs, formally documenting KVM's exact internal behavior is risky
and unnecessary.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20241009192345.1148353-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Add a lockdep assertion in kvm_unmap_gfn_range() to ensure that either
mmu_invalidate_in_progress is elevated, or that the range is being zapped
due to memslot removal (loosely detected by slots_lock being held).
Zapping SPTEs without mmu_invalidate_{in_progress,seq} protection is unsafe
as KVM's page fault path snapshots state before acquiring mmu_lock, and
thus can create SPTEs with stale information if vCPUs aren't forced to
retry faults (due to seeing an in-progress or past MMU invalidation).

Memslot removal is a special case, as the memslot is retrieved outside of
mmu_invalidate_seq, i.e. doesn't use the "standard" protections, and
instead relies on SRCU synchronization to ensure any in-flight page faults
are fully resolved before zapping SPTEs.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20241009192345.1148353-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

When performing a targeted zap on memslot removal, zap only MMU pages that
shadow guest PTEs, as zapping all SPs that "match" the gfn is inexact and
unnecessary.  Furthermore, for_each_gfn_valid_sp() arguably shouldn't
exist, because it doesn't do what most people would it expect it to do.
The "round gfn for level" adjustment that is done for direct SPs (no gPTE)
means that the exact gfn comparison will not get a match, even when a SP
does "cover" a gfn, or was even created specifically for a gfn.

For memslot deletion specifically, KVM's behavior will vary significantly
based on the size and alignment of a memslot, and in weird ways.  E.g. for
a 4KiB memslot, KVM will zap more SPs if the slot is 1GiB aligned than if
it's only 4KiB aligned.  And as described below, zapping SPs in the
aligned case overzaps for direct MMUs, as odds are good the upper-level
SPs are serving other memslots.

To iterate over all potentially-relevant gfns, KVM would need to make a
pass over the hash table for each level, with the gfn used for lookup
rounded for said level.  And then check that the SP is of the correct
level, too, e.g. to avoid over-zapping.

But even then, KVM would massively overzap, as processing every level is
all but guaranteed to zap SPs that serve other memslots, especially if the
memslot being removed is relatively small.  KVM could mitigate that issue
by processing only levels that can be possible guest huge pages, i.e. are
less likely to be re-used for other memslot, but while somewhat logical,
that's quite arbitrary and would be a bit of a mess to implement.

So, zap only SPs with gPTEs, as the resulting behavior is easy to describe,
is predictable, and is explicitly minimal, i.e. KVM only zaps SPs that
absolutely must be zapped.

Cc: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Message-ID: <20241009192345.1148353-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

AMD SEV-SNP and Intel TDX have limited access to MTRR: either it is not
advertised in CPUID or it cannot be programmed (on TDX, due to #VE on
CR0.CD clear).

This results in guests using uncached mappings where it shouldn't and
pmd/pud_set_huge() failures due to non-uniform memory type reported by
mtrr_type_lookup().

Override MTRR state, making it WB by default as the kernel does for
Hyper-V guests.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Suggested-by: Binbin Wu <binbin.wu@intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Message-ID: <20241015095818.357915-1-kirill.shutemov@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The last use of kvm_vcpu_gfn_to_pfn_atomic was removed by commit
1bbc60d0 ("KVM: x86/mmu: Remove MMU auditing")

Remove it.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Message-ID: <20241001141354.18009-3-linux@treblig.org>
[Adjust Documentation/virt/kvm/locking.rst. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

The last use of kvm_vcpu_gfn_to_pfn was removed by commit
b1624f99 ("KVM: Remove kvm_vcpu_gfn_to_page() and kvm_vcpu_gpa_to_page()")

Remove it.
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Message-ID: <20241001141354.18009-2-linux@treblig.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Pull one more io_uring fix from Jens Axboe:
 "Fix for a regression introduced in 6.12-rc2, where a condition check
  was negated and hence -EAGAIN would bubble back up up to userspace
  rather than trigger a retry condition"

* tag 'io_uring-6.12-20241019' of git://git.kernel.dk/linux:
  io_uring/rw: fix wrong NOWAIT check in io_rw_init_file()

Pull SCSI fixes from James Bottomley:
 "Fixes all in drivers. The largest is the mpi3mr which corrects a phy
  count limit that should only apply to the controller but was being
  incorrectly applied to expander phys"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: target: core: Fix null-ptr-deref in target_alloc_device()
  scsi: mpi3mr: Validate SAS port assignments
  scsi: ufs: core: Set SDEV_OFFLINE when UFS is shut down
  scsi: ufs: core: Requeue aborted request
  scsi: ufs: core: Fix the issue of ICU failure

Pull ftrace fixes from Steven Rostedt:
 "A couple of fixes to function graph infrastructure:

   - Fix allocation of idle shadow stack allocation during hotplug

     If function graph tracing is started when a CPU is offline, if it
     were come online during the trace then the idle task that
     represents the CPU will not get a shadow stack allocated for it.
     This means all function graph hooks that happen while that idle
     task is running (including in interrupt mode) will have all its
     events dropped.

     Switch over to the CPU hotplug mechanism that will have any newly
     brought on line CPU get a callback that can allocate the shadow
     stack for its idle task.

   - Fix allocation size of the ret_stack_list array

     When function graph tracing converted over to allowing more than
     one user at a time, it had to convert its shadow stack from an
     array of ret_stack structures to an array of unsigned longs. The
     shadow stacks are allocated in batches of 32 at a time and assigned
     to every running task. The batch is held by the ret_stack_list
     array.

     But when the conversion happened, instead of allocating an array of
     32 pointers, it was allocated as a ret_stack itself (PAGE_SIZE).
     This ret_stack_list gets passed to a function that iterates over
     what it believes is its size defined by the
     FTRACE_RETSTACK_ALLOC_SIZE macro (which is 32).

     Luckily (PAGE_SIZE) is greater than 32 * sizeof(long), otherwise
     this would have been an array overflow. This still should be fixed
     and the ret_stack_list should be allocated to the size it is
     expected to be as someday it may end up being bigger than
     SHADOW_STACK_SIZE"

* tag 'ftrace-v6.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  fgraph: Allocate ret_stack_list with proper size
  fgraph: Use CPU hotplug mechanism to initialize idle shadow stacks

Pull ipe fixes from Fan Wu:
 "This addresses several issues identified by Luca when attempting to
  enable IPE on Debian and systemd:

   - address issues with IPE policy update errors and policy update
     version check, improving the clarity of error messages for better
     understanding by userspace programs.

   - enable IPE policies to be signed by secondary and platform
     keyrings, facilitating broader use across general Linux
     distributions like Debian.

   - updates the IPE entry in the MAINTAINERS file to reflect the new
     tree URL and my updated email from kernel.org"

* tag 'ipe-pr-20241018' of git://git.kernel.org/pub/scm/linux/kernel/git/wufan/ipe:
  MAINTAINERS: update IPE tree url and Fan Wu's email
  ipe: fallback to platform keyring also if key in trusted keyring is rejected
  ipe: allow secondary and platform keyrings to install/update policies
  ipe: also reject policy updates with the same version
  ipe: return -ESTALE instead of -EINVAL on update when new policy has a lower version

Pull input fixes from Dmitry Torokhov:

 - a fix for Zinitix driver to not fail probing if the property enabling
   touch keys functionality is not defined. Support for touch keys was
   added in 6.12 merge window so this issue does not affect users of
   released kernels

 - a couple new vendor/device IDs in xpad driver to enable support for
   more hardware

* tag 'input-for-v6.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: zinitix - don't fail if linux,keycodes prop is absent
  Input: xpad - add support for MSI Claw A1M
  Input: xpad - add support for 8BitDo Ultimate 2C Wireless Controller

Pull 9p fixes from Dominique Martinet:
 "Mashed-up update that I sat on too long:

   - fix for multiple slabs created with the same name

   - enable multipage folios

   - theorical fix to also look for opened fids by inode if none was
     found by dentry"

[ Enabling multi-page folios should have been done during the merge
  window, but it's a one-liner, and the actual meat of the enablement
  is in netfs and already in use for other filesystems...  - Linus ]

* tag '9p-for-6.12-rc4' of https://github.com/martinetd/linux:
  9p: Avoid creating multiple slab caches with the same name
  9p: Enable multipage folios
  9p: v9fs_fid_find: also lookup by inode if not found dentry

Pull rust fixes from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Fix several issues with the 'rustc-option' macro. It includes a
     refactor from Masahiro of three '{cc,rust}-*' macros, which is not
     a fix but avoids repeating the same commands (which would be
     several lines in the case of 'rustc-option').

   - Fix conditions for 'CONFIG_HAVE_CFI_ICALL_NORMALIZE_INTEGERS'. It
     includes the addition of 'CONFIG_RUSTC_LLVM_VERSION', which is not
     a fix but is needed for the actual fix.

  And a trivial grammar fix"

* tag 'rust-fixes-6.12-2' of https://github.com/Rust-for-Linux/linux:
  cfi: fix conditions for HAVE_CFI_ICALL_NORMALIZE_INTEGERS
  kbuild: rust: add `CONFIG_RUSTC_LLVM_VERSION`
  kbuild: fix issues with rustc-option
  kbuild: refactor cc-option-yn, cc-disable-warning, rust-option-yn macros
  lib/Kconfig.debug: fix grammar in RUST_BUILD_ASSERT_ALLOW

A previous commit improved how !FMODE_NOWAIT is dealt with, but
inadvertently negated a check whilst doing so. This caused -EAGAIN to be
returned from reading files with O_NONBLOCK set. Fix up the check for
REQ_F_SUPPORT_NOWAIT.
Reported-by: Julian Orth <ju.orth@gmail.com>
Link: https://github.com/axboe/liburing/issues/1270
Fixes: f7c91343 ("io_uring/rw: allow pollable non-blocking attempts for !FMODE_NOWAIT")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The ret_stack_list is an array of ret_stack shadow stacks for the function
graph usage. When the first function graph is enabled, all tasks in the
system get a shadow stack. The ret_stack_list is a 32 element array of
pointers to these shadow stacks. It allocates the shadow stack in batches
(32 stacks at a time), assigns them to running tasks, and continues until
all tasks are covered.

When the function graph shadow stack changed from an array of
ftrace_ret_stack structures to an array of longs, the allocation of
ret_stack_list went from allocating an array of 32 elements to just a
block defined by SHADOW_STACK_SIZE. Luckily, that's defined as PAGE_SIZE
and is much more than enough to hold 32 pointers. But it is way overkill
for the amount needed to allocate.

Change the allocation of ret_stack_list back to a kcalloc() of
FTRACE_RETSTACK_ALLOC_SIZE pointers.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241018215212.23f13f40@rorschach
Fixes: 42675b72 ("function_graph: Convert ret_stack to a series of longs")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

The function graph infrastructure allocates a shadow stack for every task
when enabled. This includes the idle tasks. The first time the function
graph is invoked, the shadow stacks are created and never freed until the
task exits. This includes the idle tasks.

Only the idle tasks that were for online CPUs had their shadow stacks
created when function graph tracing started. If function graph tracing is
enabled and a CPU comes online, the idle task representing that CPU will
not have its shadow stack created, and all function graph tracing for that
idle task will be silently dropped.

Instead, use the CPU hotplug mechanism to allocate the idle shadow stacks.
This will include idle tasks for CPUs that come online during tracing.

This issue can be reproduced by:

 # cd /sys/kernel/tracing
 # echo 0 > /sys/devices/system/cpu/cpu1/online
 # echo 0 > set_ftrace_pid
 # echo function_graph > current_tracer
 # echo 1 > options/funcgraph-proc
 # echo 1 > /sys/devices/system/cpu/cpu1
 # grep '<idle>' per_cpu/cpu1/trace | head

Before, nothing would show up.

After:
 1)    <idle>-0    |   0.811 us    |                        __enqueue_entity();
 1)    <idle>-0    |   5.626 us    |                      } /* enqueue_entity */
 1)    <idle>-0    |               |                      dl_server_update_idle_time() {
 1)    <idle>-0    |               |                        dl_scaled_delta_exec() {
 1)    <idle>-0    |   0.450 us    |                          arch_scale_cpu_capacity();
 1)    <idle>-0    |   1.242 us    |                        }
 1)    <idle>-0    |   1.908 us    |                      }
 1)    <idle>-0    |               |                      dl_server_start() {
 1)    <idle>-0    |               |                        enqueue_dl_entity() {
 1)    <idle>-0    |               |                          task_contending() {

Note, if tracing stops and restarts, the old way would then initialize
the onlined CPUs.

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/20241018214300.6df82178@rorschach
Fixes: 868baf07 ("ftrace: Fix memory leak with function graph and cpu hotplug")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>