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  1. Jan 24, 2023
  3. Jan 18, 2023
    • Greg Kroah-Hartman's avatar
      Linux 5.15.89 · 3bcc86eb
      Greg Kroah-Hartman authored 
      Link: https://lore.kernel.org/r/20230116154747.036911298@linuxfoundation.org


Tested-by: default avatarShuah Khan <skhan@linuxfoundation.org>
Tested-by: default avatarBagas Sanjaya <bagasdotme@gmail.com>
Tested-by: default avatarJon Hunter <jonathanh@nvidia.com>
Tested-by: default avatarLinux Kernel Functional Testing <lkft@linaro.org>
Tested-by: default avatarSudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Tested-by: default avatarAllen Pais <apais@linux.microsoft.com>
Tested-by: default avatarGuenter Roeck <linux@roeck-us.net>
Tested-by: default avatarKelsey Steele <kelseysteele@linux.microsoft.com>
Tested-by: default avatarRon Economos <re@w6rz.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      v5.15.89
      3bcc86eb
    • Mario Limonciello's avatar
      pinctrl: amd: Add dynamic debugging for active GPIOs · 37c18ef4
      Mario Limonciello authored 
      
commit 1d66e379 upstream.

Some laptops have been reported to wake up from s2idle when plugging
in the AC adapter or by closing the lid.  This is a surprising
behavior that is further clarified by commit cb3e7d62 ("PM:
wakeup: Add extra debugging statement for multiple active IRQs").

With that commit in place the following interaction can be seen
when the lid is closed:

[   28.946038] PM: suspend-to-idle
[   28.946083] ACPI: EC: ACPI EC GPE status set
[   28.946101] ACPI: PM: Rearming ACPI SCI for wakeup
[   28.950152] Timekeeping suspended for 3.320 seconds
[   28.950152] PM: Triggering wakeup from IRQ 9
[   28.950152] ACPI: EC: ACPI EC GPE status set
[   28.950152] ACPI: EC: ACPI EC GPE dispatched
[   28.995057] ACPI: EC: ACPI EC work flushed
[   28.995075] ACPI: PM: Rearming ACPI SCI for wakeup
[   28.995131] PM: Triggering wakeup from IRQ 9
[   28.995271] ACPI: EC: ACPI EC GPE status set
[   28.995291] ACPI: EC: ACPI EC GPE dispatched
[   29.098556] ACPI: EC: ACPI EC work flushed
[   29.207020] ACPI: EC: ACPI EC work flushed
[   29.207037] ACPI: PM: Rearming ACPI SCI for wakeup
[   29.211095] Timekeeping suspended for 0.739 seconds
[   29.211095] PM: Triggering wakeup from IRQ 9
[   29.211079] PM: Triggering wakeup from IRQ 7
[   29.211095] ACPI: PM: ACPI non-EC GPE wakeup
[   29.211095] PM: resume from suspend-to-idle

* IRQ9 on this laptop is used for the ACPI SCI.
* IRQ7 on this laptop is used for the GPIO controller.

What has occurred is when the lid was closed the EC woke up the
SoC from it's deepest sleep state and the kernel's s2idle loop
processed all EC events.  When it was finished processing EC events,
it checked for any other reasons to wake (break the s2idle loop).

The IRQ for the GPIO controller was active so the loop broke, and
then this IRQ was processed.  This is not a kernel bug but it is
certainly a surprising behavior, and to better debug it we should
have a dynamic debugging message that we can enact to catch it.

Acked-by: default avatarBasavaraj Natikar <Basavaraj.Natikar@amd.com>
Acked-by: default avatarKai-Heng Feng <kai.heng.feng@canonical.com>
Acked-by: default avatarMark Pearson <markpearson@lenovo.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20221013134729.5592-2-mario.limonciello@amd.com


Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      37c18ef4
    • Ferry Toth's avatar
      Revert "usb: ulpi: defer ulpi_register on ulpi_read_id timeout" · a5841b81
      Ferry Toth authored 
      commit b659b613 upstream.

This reverts commit 8a7b31d5.

This patch results in some qemu test failures, specifically xilinx-zynq-a9
machine and zynq-zc702 as well as zynq-zed devicetree files, when trying
to boot from USB drive.

Link: https://lore.kernel.org/lkml/20221220194334.GA942039@roeck-us.net/


Fixes: 8a7b31d5 ("usb: ulpi: defer ulpi_register on ulpi_read_id timeout")
Cc: stable@vger.kernel.org
Reported-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarFerry Toth <ftoth@exalondelft.nl>
Link: https://lore.kernel.org/r/20221222205302.45761-1-ftoth@exalondelft.nl


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      a5841b81
    • Jens Axboe's avatar
      block: handle bio_split_to_limits() NULL return · 7ec9a45f
      Jens Axboe authored 
      
commit 613b1488 upstream.

This can't happen right now, but in preparation for allowing
bio_split_to_limits() returning NULL if it ended the bio, check for it
in all the callers.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      7ec9a45f
    • Jens Axboe's avatar
      io_uring/io-wq: only free worker if it was allocated for creation · ba86db02
      Jens Axboe authored 
      
commit e6db6f93 upstream.

We have two types of task_work based creation, one is using an existing
worker to setup a new one (eg when going to sleep and we have no free
workers), and the other is allocating a new worker. Only the latter
should be freed when we cancel task_work creation for a new worker.

Fixes: af82425c ("io_uring/io-wq: free worker if task_work creation is canceled")
Reported-by: default avatar <syzbot+d56ec896af3637bdb7e4@syzkaller.appspotmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ba86db02
    • Jens Axboe's avatar
      io_uring/io-wq: free worker if task_work creation is canceled · bb135bcc
      Jens Axboe authored 
      
commit af82425c upstream.

If we cancel the task_work, the worker will never come into existance.
As this is the last reference to it, ensure that we get it freed
appropriately.

Cc: stable@vger.kernel.org
Reported-by: default avatar진호 <wnwlsgh98@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      bb135bcc
    • Sreekanth Reddy's avatar
      scsi: mpt3sas: Remove scsi_dma_map() error messages · 63c2fa09
      Sreekanth Reddy authored 
      commit 0c25422d upstream.

When scsi_dma_map() fails by returning a sges_left value less than zero,
the amount of logging produced can be extremely high.  In a recent end-user
environment, 1200 messages per second were being sent to the log buffer.
This eventually overwhelmed the system and it stalled.

These error messages are not needed. Remove them.

Link: https://lore.kernel.org/r/20220303140203.12642-1-sreekanth.reddy@broadcom.com


Suggested-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarSreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      63c2fa09
    • Johan Hovold's avatar
      efi: fix NULL-deref in init error path · e2ea5556
      Johan Hovold authored 
      
[ Upstream commit 703c13fe ]

In cases where runtime services are not supported or have been disabled,
the runtime services workqueue will never have been allocated.

Do not try to destroy the workqueue unconditionally in the unlikely
event that EFI initialisation fails to avoid dereferencing a NULL
pointer.

Fixes: 98086df8 ("efi: add missed destroy_workqueue when efisubsys_init fails")
Cc: stable@vger.kernel.org
Cc: Li Heng <liheng40@huawei.com>
Signed-off-by: default avatarJohan Hovold <johan+linaro@kernel.org>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
      e2ea5556
    • Mark Rutland's avatar
      arm64: cmpxchg_double*: hazard against entire exchange variable · 94b6cf84
      Mark Rutland authored 
      
[ Upstream commit 031af500 ]

The inline assembly for arm64's cmpxchg_double*() implementations use a
+Q constraint to hazard against other accesses to the memory location
being exchanged. However, the pointer passed to the constraint is a
pointer to unsigned long, and thus the hazard only applies to the first
8 bytes of the location.

GCC can take advantage of this, assuming that other portions of the
location are unchanged, leading to a number of potential problems.

This is similar to what we fixed back in commit:

  fee960be ("arm64: xchg: hazard against entire exchange variable")

... but we forgot to adjust cmpxchg_double*() similarly at the same
time.

The same problem applies, as demonstrated with the following test:

| struct big {
|         u64 lo, hi;
| } __aligned(128);
|
| unsigned long foo(struct big *b)
| {
|         u64 hi_old, hi_new;
|
|         hi_old = b->hi;
|         cmpxchg_double_local(&b->lo, &b->hi, 0x12, 0x34, 0x56, 0x78);
|         hi_new = b->hi;
|
|         return hi_old ^ hi_new;
| }

... which GCC 12.1.0 compiles as:

| 0000000000000000 <foo>:
|    0:   d503233f        paciasp
|    4:   aa0003e4        mov     x4, x0
|    8:   1400000e        b       40 <foo+0x40>
|    c:   d2800240        mov     x0, #0x12                       // #18
|   10:   d2800681        mov     x1, #0x34                       // #52
|   14:   aa0003e5        mov     x5, x0
|   18:   aa0103e6        mov     x6, x1
|   1c:   d2800ac2        mov     x2, #0x56                       // #86
|   20:   d2800f03        mov     x3, #0x78                       // #120
|   24:   48207c82        casp    x0, x1, x2, x3, [x4]
|   28:   ca050000        eor     x0, x0, x5
|   2c:   ca060021        eor     x1, x1, x6
|   30:   aa010000        orr     x0, x0, x1
|   34:   d2800000        mov     x0, #0x0                        // #0    <--- BANG
|   38:   d50323bf        autiasp
|   3c:   d65f03c0        ret
|   40:   d2800240        mov     x0, #0x12                       // #18
|   44:   d2800681        mov     x1, #0x34                       // #52
|   48:   d2800ac2        mov     x2, #0x56                       // #86
|   4c:   d2800f03        mov     x3, #0x78                       // #120
|   50:   f9800091        prfm    pstl1strm, [x4]
|   54:   c87f1885        ldxp    x5, x6, [x4]
|   58:   ca0000a5        eor     x5, x5, x0
|   5c:   ca0100c6        eor     x6, x6, x1
|   60:   aa0600a6        orr     x6, x5, x6
|   64:   b5000066        cbnz    x6, 70 <foo+0x70>
|   68:   c8250c82        stxp    w5, x2, x3, [x4]
|   6c:   35ffff45        cbnz    w5, 54 <foo+0x54>
|   70:   d2800000        mov     x0, #0x0                        // #0     <--- BANG
|   74:   d50323bf        autiasp
|   78:   d65f03c0        ret

Notice that at the lines with "BANG" comments, GCC has assumed that the
higher 8 bytes are unchanged by the cmpxchg_double() call, and that
`hi_old ^ hi_new` can be reduced to a constant zero, for both LSE and
LL/SC versions of cmpxchg_double().

This patch fixes the issue by passing a pointer to __uint128_t into the
+Q constraint, ensuring that the compiler hazards against the entire 16
bytes being modified.

With this change, GCC 12.1.0 compiles the above test as:

| 0000000000000000 <foo>:
|    0:   f9400407        ldr     x7, [x0, #8]
|    4:   d503233f        paciasp
|    8:   aa0003e4        mov     x4, x0
|    c:   1400000f        b       48 <foo+0x48>
|   10:   d2800240        mov     x0, #0x12                       // #18
|   14:   d2800681        mov     x1, #0x34                       // #52
|   18:   aa0003e5        mov     x5, x0
|   1c:   aa0103e6        mov     x6, x1
|   20:   d2800ac2        mov     x2, #0x56                       // #86
|   24:   d2800f03        mov     x3, #0x78                       // #120
|   28:   48207c82        casp    x0, x1, x2, x3, [x4]
|   2c:   ca050000        eor     x0, x0, x5
|   30:   ca060021        eor     x1, x1, x6
|   34:   aa010000        orr     x0, x0, x1
|   38:   f9400480        ldr     x0, [x4, #8]
|   3c:   d50323bf        autiasp
|   40:   ca0000e0        eor     x0, x7, x0
|   44:   d65f03c0        ret
|   48:   d2800240        mov     x0, #0x12                       // #18
|   4c:   d2800681        mov     x1, #0x34                       // #52
|   50:   d2800ac2        mov     x2, #0x56                       // #86
|   54:   d2800f03        mov     x3, #0x78                       // #120
|   58:   f9800091        prfm    pstl1strm, [x4]
|   5c:   c87f1885        ldxp    x5, x6, [x4]
|   60:   ca0000a5        eor     x5, x5, x0
|   64:   ca0100c6        eor     x6, x6, x1
|   68:   aa0600a6        orr     x6, x5, x6
|   6c:   b5000066        cbnz    x6, 78 <foo+0x78>
|   70:   c8250c82        stxp    w5, x2, x3, [x4]
|   74:   35ffff45        cbnz    w5, 5c <foo+0x5c>
|   78:   f9400480        ldr     x0, [x4, #8]
|   7c:   d50323bf        autiasp
|   80:   ca0000e0        eor     x0, x7, x0
|   84:   d65f03c0        ret

... sampling the high 8 bytes before and after the cmpxchg, and
performing an EOR, as we'd expect.

For backporting, I've tested this atop linux-4.9.y with GCC 5.5.0. Note
that linux-4.9.y is oldest currently supported stable release, and
mandates GCC 5.1+. Unfortunately I couldn't get a GCC 5.1 binary to run
on my machines due to library incompatibilities.

I've also used a standalone test to check that we can use a __uint128_t
pointer in a +Q constraint at least as far back as GCC 4.8.5 and LLVM
3.9.1.

Fixes: 5284e1b4 ("arm64: xchg: Implement cmpxchg_double")
Fixes: e9a4b795 ("arm64: cmpxchg_dbl: patch in lse instructions when supported by the CPU")
Reported-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/lkml/Y6DEfQXymYVgL3oJ@boqun-archlinux/


Reported-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/lkml/Y6GXoO4qmH9OIZ5Q@hirez.programming.kicks-ass.net/


Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Cc: stable@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20230104151626.3262137-1-mark.rutland@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
      94b6cf84
    • Mark Rutland's avatar
      arm64: atomics: remove LL/SC trampolines · 3891fa49
      Mark Rutland authored 
      
[ Upstream commit b2c3ccbd ]

When CONFIG_ARM64_LSE_ATOMICS=y, each use of an LL/SC atomic results in
a fragment of code being generated in a subsection without a clear
association with its caller. A trampoline in the caller branches to the
LL/SC atomic with with a direct branch, and the atomic directly branches
back into its trampoline.

This breaks backtracing, as any PC within the out-of-line fragment will
be symbolized as an offset from the nearest prior symbol (which may not
be the function using the atomic), and since the atomic returns with a
direct branch, the caller's PC may be missing from the backtrace.

For example, with secondary_start_kernel() hacked to contain
atomic_inc(NULL), the resulting exception can be reported as being taken
from cpus_are_stuck_in_kernel():

| Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
| Mem abort info:
|   ESR = 0x0000000096000004
|   EC = 0x25: DABT (current EL), IL = 32 bits
|   SET = 0, FnV = 0
|   EA = 0, S1PTW = 0
|   FSC = 0x04: level 0 translation fault
| Data abort info:
|   ISV = 0, ISS = 0x00000004
|   CM = 0, WnR = 0
| [0000000000000000] user address but active_mm is swapper
| Internal error: Oops: 96000004 [#1] PREEMPT SMP
| Modules linked in:
| CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.19.0-11219-geb555cb5b794-dirty #3
| Hardware name: linux,dummy-virt (DT)
| pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : cpus_are_stuck_in_kernel+0xa4/0x120
| lr : secondary_start_kernel+0x164/0x170
| sp : ffff80000a4cbe90
| x29: ffff80000a4cbe90 x28: 0000000000000000 x27: 0000000000000000
| x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
| x23: 0000000000000000 x22: 0000000000000000 x21: 0000000000000000
| x20: 0000000000000001 x19: 0000000000000001 x18: 0000000000000008
| x17: 3030383832343030 x16: 3030303030307830 x15: ffff80000a4cbab0
| x14: 0000000000000001 x13: 5d31666130663133 x12: 3478305b20313030
| x11: 3030303030303078 x10: 3020726f73736563 x9 : 726f737365636f72
| x8 : ffff800009ff2ef0 x7 : 0000000000000003 x6 : 0000000000000000
| x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000100
| x2 : 0000000000000000 x1 : ffff0000029bd880 x0 : 0000000000000000
| Call trace:
|  cpus_are_stuck_in_kernel+0xa4/0x120
|  __secondary_switched+0xb0/0xb4
| Code: 35ffffa3 17fffc6c d53cd040 f9800011 (885f7c01)
| ---[ end trace 0000000000000000 ]---

This is confusing and hinders debugging, and will be problematic for
CONFIG_LIVEPATCH as these cases cannot be unwound reliably.

This is very similar to recent issues with out-of-line exception fixups,
which were removed in commits:

  35d67794 ("arm64: lib: __arch_clear_user(): fold fixups into body")
  4012e0e2 ("arm64: lib: __arch_copy_from_user(): fold fixups into body")
  139f9ab7 ("arm64: lib: __arch_copy_to_user(): fold fixups into body")

When the trampolines were introduced in commit:

  addfc386 ("arm64: atomics: avoid out-of-line ll/sc atomics")

The rationale was to improve icache performance by grouping the LL/SC
atomics together. This has never been measured, and this theoretical
benefit is outweighed by other factors:

* As the subsections are collapsed into sections at object file
  granularity, these are spread out throughout the kernel and can share
  cachelines with unrelated code regardless.

* GCC 12.1.0 has been observed to place the trampoline out-of-line in
  specialised __ll_sc_*() functions, introducing more branching than was
  intended.

* Removing the trampolines has been observed to shrink a defconfig
  kernel Image by 64KiB when building with GCC 12.1.0.

This patch removes the LL/SC trampolines, meaning that the LL/SC atomics
will be inlined into their callers (or placed in out-of line functions
using regular BL/RET pairs). When CONFIG_ARM64_LSE_ATOMICS=y, the LL/SC
atomics are always called in an unlikely branch, and will be placed in a
cold portion of the function, so this should have minimal impact to the
hot paths.

Other than the improved backtracing, there should be no functional
change as a result of this patch.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220817155914.3975112-2-mark.rutland@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Stable-dep-of: 031af500 ("arm64: cmpxchg_double*: hazard against entire exchange variable")
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
      3891fa49
    • Mark Rutland's avatar
      arm64: atomics: format whitespace consistently · 61e86339
      Mark Rutland authored 
      
[ Upstream commit 8e6082e9 ]

The code for the atomic ops is formatted inconsistently, and while this
is not a functional problem it is rather distracting when working on
them.

Some have ops have consistent indentation, e.g.

| #define ATOMIC_OP_ADD_RETURN(name, mb, cl...)                           \
| static inline int __lse_atomic_add_return##name(int i, atomic_t *v)     \
| {                                                                       \
|         u32 tmp;                                                        \
|                                                                         \
|         asm volatile(                                                   \
|         __LSE_PREAMBLE                                                  \
|         "       ldadd" #mb "    %w[i], %w[tmp], %[v]\n"                 \
|         "       add     %w[i], %w[i], %w[tmp]"                          \
|         : [i] "+r" (i), [v] "+Q" (v->counter), [tmp] "=&r" (tmp)        \
|         : "r" (v)                                                       \
|         : cl);                                                          \
|                                                                         \
|         return i;                                                       \
| }

While others have negative indentation for some lines, and/or have
misaligned trailing backslashes, e.g.

| static inline void __lse_atomic_##op(int i, atomic_t *v)                        \
| {                                                                       \
|         asm volatile(                                                   \
|         __LSE_PREAMBLE                                                  \
| "       " #asm_op "     %w[i], %[v]\n"                                  \
|         : [i] "+r" (i), [v] "+Q" (v->counter)                           \
|         : "r" (v));                                                     \
| }

This patch makes the indentation consistent and also aligns the trailing
backslashes. This makes the code easier to read for those (like myself)
who are easily distracted by these inconsistencies.

This is intended as a cleanup.
There should be no functional change as a result of this patch.

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Acked-by: default avatarWill Deacon <will@kernel.org>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20211210151410.2782645-2-mark.rutland@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Stable-dep-of: 031af500 ("arm64: cmpxchg_double*: hazard against entire exchange variable")
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
      61e86339
    • Pavel Begunkov's avatar
      io_uring: lock overflowing for IOPOLL · ed4629d1
      Pavel Begunkov authored 
      
commit 544d163d upstream.

syzbot reports an issue with overflow filling for IOPOLL:

WARNING: CPU: 0 PID: 28 at io_uring/io_uring.c:734 io_cqring_event_overflow+0x1c0/0x230 io_uring/io_uring.c:734
CPU: 0 PID: 28 Comm: kworker/u4:1 Not tainted 6.2.0-rc3-syzkaller-16369-g358a161a6a9e #0
Workqueue: events_unbound io_ring_exit_work
Call trace:
 io_cqring_event_overflow+0x1c0/0x230 io_uring/io_uring.c:734
 io_req_cqe_overflow+0x5c/0x70 io_uring/io_uring.c:773
 io_fill_cqe_req io_uring/io_uring.h:168 [inline]
 io_do_iopoll+0x474/0x62c io_uring/rw.c:1065
 io_iopoll_try_reap_events+0x6c/0x108 io_uring/io_uring.c:1513
 io_uring_try_cancel_requests+0x13c/0x258 io_uring/io_uring.c:3056
 io_ring_exit_work+0xec/0x390 io_uring/io_uring.c:2869
 process_one_work+0x2d8/0x504 kernel/workqueue.c:2289
 worker_thread+0x340/0x610 kernel/workqueue.c:2436
 kthread+0x12c/0x158 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:863

There is no real problem for normal IOPOLL as flush is also called with
uring_lock taken, but it's getting more complicated for IOPOLL|SQPOLL,
for which __io_cqring_overflow_flush() happens from the CQ waiting path.

Reported-and-tested-by: default avatar <syzbot+6805087452d72929404e@syzkaller.appspotmail.com>
Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
      ed4629d1
    • Paolo Bonzini's avatar
      KVM: x86: Do not return host topology information from KVM_GET_SUPPORTED_CPUID · fbf50151
      Paolo Bonzini authored 
      
[ Upstream commit 45e966fc ]

Passing the host topology to the guest is almost certainly wrong
and will confuse the scheduler.  In addition, several fields of
these CPUID leaves vary on each processor; it is simply impossible to
return the right values from KVM_GET_SUPPORTED_CPUID in such a way that
they can be passed to KVM_SET_CPUID2.

The values that will most likely prevent confusion are all zeroes.
Userspace will have to override it anyway if it wishes to present a
specific topology to the guest.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
      fbf50151