Список изменений в Linux 5.4.173

 
ALSA: hda/realtek - Fix silent output on Gigabyte X570 Aorus Master after reboot from Windows [+ + +]
Author: Christian Lachner <gladiac@gmail.com>
Date:   Mon Jan 3 15:05:17 2022 +0100

    ALSA: hda/realtek - Fix silent output on Gigabyte X570 Aorus Master after reboot from Windows
    
    commit c1933008679586b20437280463110c967d66f865 upstream.
    
    This patch addresses an issue where after rebooting from Windows into Linux
    there would be no audio output.
    
    It turns out that the Realtek Audio driver on Windows changes some coeffs
    which are not being reset/reinitialized when rebooting the machine. As a
    result, there is no audio output until these coeffs are being reset to
    their initial state. This patch takes care of that by setting known-good
    (initial) values to the coeffs.
    
    We initially relied upon alc1220_fixup_clevo_p950() to fix some pins in the
    connection list. However, it also sets coef 0x7 which does not need to be
    touched. Furthermore, to prevent mixing device-specific quirks I introduced
    a new alc1220_fixup_gb_x570() which is heavily based on
    alc1220_fixup_clevo_p950() but does not set coeff 0x7 and fixes the coeffs
    that are actually needed instead.
    
    This new alc1220_fixup_gb_x570() is believed to also work for other boards,
    like the Gigabyte X570 Aorus Extreme and the newer Gigabyte Aorus X570S
    Master. However, as there is no way for me to test these I initially only
    enable this new behaviour for the mainboard I have which is the Gigabyte
    X570(non-S) Aorus Master.
    
    I tested this patch on the 5.15 branch as well as on master and it is
    working well for me.
    
    BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=205275
    Signed-off-by: Christian Lachner <gladiac@gmail.com>
    Fixes: 0d45e86d2267d ("ALSA: hda/realtek - Fix silent output on Gigabyte X570 Aorus Master")
    Cc: <stable@vger.kernel.org>
    Link: https://lore.kernel.org/r/20220103140517.30273-2-gladiac@gmail.com
    Signed-off-by: Takashi Iwai <tiwai@suse.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 
ARM: 9025/1: Kconfig: CPU_BIG_ENDIAN depends on !LD_IS_LLD [+ + +]
Author: Nick Desaulniers <ndesaulniers@google.com>
Date:   Tue Nov 17 00:46:39 2020 +0100

    ARM: 9025/1: Kconfig: CPU_BIG_ENDIAN depends on !LD_IS_LLD
    
    commit 28187dc8ebd938d574edfc6d9e0f9c51c21ff3f4 upstream.
    
    LLD does not yet support any big endian architectures. Make this config
    non-selectable when using LLD until LLD is fixed.
    
    Link: https://github.com/ClangBuiltLinux/linux/issues/965
    
    Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
    Tested-by: Nathan Chancellor <natechancellor@gmail.com>
    Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
    Reported-by: kbuild test robot <lkp@intel.com>
    Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
    Cc: Anders Roxell <anders.roxell@linaro.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 
devtmpfs regression fix: reconfigure on each mount [+ + +]
Author: NeilBrown <neilb@suse.de>
Date:   Mon Jan 17 09:07:26 2022 +1100

    devtmpfs regression fix: reconfigure on each mount
    
    commit a6097180d884ddab769fb25588ea8598589c218c upstream.
    
    Prior to Linux v5.4 devtmpfs used mount_single() which treats the given
    mount options as "remount" options, so it updates the configuration of
    the single super_block on each mount.
    
    Since that was changed, the mount options used for devtmpfs are ignored.
    This is a regression which affect systemd - which mounts devtmpfs with
    "-o mode=755,size=4m,nr_inodes=1m".
    
    This patch restores the "remount" effect by calling reconfigure_single()
    
    Fixes: d401727ea0d7 ("devtmpfs: don't mix {ramfs,shmem}_fill_super() with mount_single()")
    Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
    Cc: Al Viro <viro@zeniv.linux.org.uk>
    Signed-off-by: NeilBrown <neilb@suse.de>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 
firmware: qemu_fw_cfg: fix kobject leak in probe error path [+ + +]
Author: Johan Hovold <johan@kernel.org>
Date:   Wed Dec 1 14:25:26 2021 +0100

    firmware: qemu_fw_cfg: fix kobject leak in probe error path
    
    commit 47a1db8e797da01a1309bf42e0c0d771d4e4d4f3 upstream.
    
    An initialised kobject must be freed using kobject_put() to avoid
    leaking associated resources (e.g. the object name).
    
    Commit fe3c60684377 ("firmware: Fix a reference count leak.") "fixed"
    the leak in the first error path of the file registration helper but
    left the second one unchanged. This "fix" would however result in a NULL
    pointer dereference due to the release function also removing the never
    added entry from the fw_cfg_entry_cache list. This has now been
    addressed.
    
    Fix the remaining kobject leak by restoring the common error path and
    adding the missing kobject_put().
    
    Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device")
    Cc: stable@vger.kernel.org      # 4.6
    Cc: Gabriel Somlo <somlo@cmu.edu>
    Signed-off-by: Johan Hovold <johan@kernel.org>
    Link: https://lore.kernel.org/r/20211201132528.30025-3-johan@kernel.org
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware: qemu_fw_cfg: fix NULL-pointer deref on duplicate entries [+ + +]
Author: Johan Hovold <johan@kernel.org>
Date:   Wed Dec 1 14:25:25 2021 +0100

    firmware: qemu_fw_cfg: fix NULL-pointer deref on duplicate entries
    
    commit d3e305592d69e21e36b76d24ca3c01971a2d09be upstream.
    
    Commit fe3c60684377 ("firmware: Fix a reference count leak.") "fixed"
    a kobject leak in the file registration helper by properly calling
    kobject_put() for the entry in case registration of the object fails
    (e.g. due to a name collision).
    
    This would however result in a NULL pointer dereference when the
    release function tries to remove the never added entry from the
    fw_cfg_entry_cache list.
    
    Fix this by moving the list-removal out of the release function.
    
    Note that the offending commit was one of the benign looking umn.edu
    fixes which was reviewed but not reverted. [1][2]
    
    [1] https://lore.kernel.org/r/202105051005.49BFABCE@keescook
    [2] https://lore.kernel.org/all/YIg7ZOZvS3a8LjSv@kroah.com
    
    Fixes: fe3c60684377 ("firmware: Fix a reference count leak.")
    Cc: stable@vger.kernel.org      # 5.8
    Cc: Qiushi Wu <wu000273@umn.edu>
    Cc: Kees Cook <keescook@chromium.org>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Johan Hovold <johan@kernel.org>
    Link: https://lore.kernel.org/r/20211201132528.30025-2-johan@kernel.org
    Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

firmware: qemu_fw_cfg: fix sysfs information leak [+ + +]
Author: Johan Hovold <johan@kernel.org>
Date:   Wed Dec 1 14:25:27 2021 +0100

    firmware: qemu_fw_cfg: fix sysfs information leak
    
    commit 1b656e9aad7f4886ed466094d1dc5ee4dd900d20 upstream.
    
    Make sure to always NUL-terminate file names retrieved from the firmware
    to avoid accessing data beyond the entry slab buffer and exposing it
    through sysfs in case the firmware data is corrupt.
    
    Fixes: 75f3e8e47f38 ("firmware: introduce sysfs driver for QEMU's fw_cfg device")
    Cc: stable@vger.kernel.org      # 4.6
    Cc: Gabriel Somlo <somlo@cmu.edu>
    Signed-off-by: Johan Hovold <johan@kernel.org>
    Link: https://lore.kernel.org/r/20211201132528.30025-4-johan@kernel.org
    Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 
kbuild: Add $(KBUILD_HOSTLDFLAGS) to 'has_libelf' test [+ + +]
Author: Nathan Chancellor <nathan@kernel.org>
Date:   Thu Apr 22 13:19:14 2021 -0700

    kbuild: Add $(KBUILD_HOSTLDFLAGS) to 'has_libelf' test
    
    commit f634ca650f724347892068489c7920631a3aac6a upstream.
    
    Normally, invocations of $(HOSTCC) include $(KBUILD_HOSTLDFLAGS), which
    in turn includes $(HOSTLDFLAGS), which allows users to pass in their own
    flags when linking. However, the 'has_libelf' test does not, meaning
    that if a user requests a specific linker via HOSTLDFLAGS=-fuse-ld=...,
    it is not respected and the build might error.
    
    For example, if a user building with clang wants to use all of the LLVM
    tools without any GNU tools, they might remove all of the GNU tools from
    their system or PATH then build with
    
    $ make HOSTLDFLAGS=-fuse-ld=lld LLVM=1 LLVM_IAS=1
    
    which says use all of the LLVM tools, the integrated assembler, and
    ld.lld for linking host executables. Without this change, the build will
    error because $(HOSTCC) uses its default linker, rather than the one
    requested via -fuse-ld=..., which is GNU ld in clang's case in a default
    configuration.
    
    error: Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please
    install libelf-dev, libelf-devel or elfutils-libelf-devel
    make[1]: *** [Makefile:1260: prepare-objtool] Error 1
    
    Add $(KBUILD_HOSTLDFLAGS) to the 'has_libelf' test so that the linker
    choice is respected.
    
    Link: https://github.com/ClangBuiltLinux/linux/issues/479
    Signed-off-by: Nathan Chancellor <nathan@kernel.org>
    Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
    Signed-off-by: Paul Barker <paul.barker@sancloud.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 
KVM: s390: Clarify SIGP orders versus STOP/RESTART [+ + +]
Author: Eric Farman <farman@linux.ibm.com>
Date:   Mon Dec 13 22:05:50 2021 +0100

    KVM: s390: Clarify SIGP orders versus STOP/RESTART
    
    commit 812de04661c4daa7ac385c0dfd62594540538034 upstream.
    
    With KVM_CAP_S390_USER_SIGP, there are only five Signal Processor
    orders (CONDITIONAL EMERGENCY SIGNAL, EMERGENCY SIGNAL, EXTERNAL CALL,
    SENSE, and SENSE RUNNING STATUS) which are intended for frequent use
    and thus are processed in-kernel. The remainder are sent to userspace
    with the KVM_CAP_S390_USER_SIGP capability. Of those, three orders
    (RESTART, STOP, and STOP AND STORE STATUS) have the potential to
    inject work back into the kernel, and thus are asynchronous.
    
    Let's look for those pending IRQs when processing one of the in-kernel
    SIGP orders, and return BUSY (CC2) if one is in process. This is in
    agreement with the Principles of Operation, which states that only one
    order can be "active" on a CPU at a time.
    
    Cc: stable@vger.kernel.org
    Suggested-by: David Hildenbrand <david@redhat.com>
    Signed-off-by: Eric Farman <farman@linux.ibm.com>
    Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
    Acked-by: David Hildenbrand <david@redhat.com>
    Link: https://lore.kernel.org/r/20211213210550.856213-2-farman@linux.ibm.com
    [borntraeger@linux.ibm.com: add stable tag]
    Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

KVM: x86: remove PMU FIXED_CTR3 from msrs_to_save_all [+ + +]
Author: Wei Wang <wei.w.wang@intel.com>
Date:   Fri Dec 17 07:49:34 2021 -0500

    KVM: x86: remove PMU FIXED_CTR3 from msrs_to_save_all
    
    commit 9fb12fe5b93b94b9e607509ba461e17f4cc6a264 upstream.
    
    The fixed counter 3 is used for the Topdown metrics, which hasn't been
    enabled for KVM guests. Userspace accessing to it will fail as it's not
    included in get_fixed_pmc(). This breaks KVM selftests on ICX+ machines,
    which have this counter.
    
    To reproduce it on ICX+ machines, ./state_test reports:
    ==== Test Assertion Failure ====
    lib/x86_64/processor.c:1078: r == nmsrs
    pid=4564 tid=4564 - Argument list too long
    1  0x000000000040b1b9: vcpu_save_state at processor.c:1077
    2  0x0000000000402478: main at state_test.c:209 (discriminator 6)
    3  0x00007fbe21ed5f92: ?? ??:0
    4  0x000000000040264d: _start at ??:?
     Unexpected result from KVM_GET_MSRS, r: 17 (failed MSR was 0x30c)
    
    With this patch, it works well.
    
    Signed-off-by: Wei Wang <wei.w.wang@intel.com>
    Message-Id: <20211217124934.32893-1-wei.w.wang@intel.com>
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
    Fixes: e2ada66ec418 ("kvm: x86: Add Intel PMU MSRs to msrs_to_save[]")
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 
Linux: Linux 5.4.173 [+ + +]
Author: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date:   Thu Jan 20 09:19:19 2022 +0100

    Linux 5.4.173
    
    Link: https://lore.kernel.org/r/20220118160450.062004175@linuxfoundation.org
    Tested-by: Florian Fainelli <f.fainelli@gmail.com>
    Tested-by: Jon Hunter <jonathanh@nvidia.com>
    Tested-by: Shuah Khan <skhan@linuxfoundation.org>
    Tested-by: Guenter Roeck <linux@roeck-us.net>
    Tested-by: Hulk Robot <hulkrobot@huawei.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 
media: uvcvideo: fix division by zero at stream start [+ + +]
Author: Johan Hovold <johan@kernel.org>
Date:   Tue Oct 26 11:55:11 2021 +0200

    media: uvcvideo: fix division by zero at stream start
    
    commit 8aa637bf6d70d2fb2ad4d708d8b9dd02b1c095df upstream.
    
    Add the missing bulk-endpoint max-packet sanity check to
    uvc_video_start_transfer() to avoid division by zero in
    uvc_alloc_urb_buffers() in case a malicious device has broken
    descriptors (or when doing descriptor fuzz testing).
    
    Note that USB core will reject URBs submitted for endpoints with zero
    wMaxPacketSize but that drivers doing packet-size calculations still
    need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip
    endpoint descriptors with maxpacket=0")).
    
    Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
    Cc: stable@vger.kernel.org      # 2.6.26
    Signed-off-by: Johan Hovold <johan@kernel.org>
    Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
    Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
    Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 
mtd: fixup CFI on ixp4xx [+ + +]
Author: Arnd Bergmann <arnd@arndb.de>
Date:   Mon Sep 27 16:10:37 2021 +0200

    mtd: fixup CFI on ixp4xx
    
    commit 603362b4a58393061dcfed1c7f0d0fd4aba61126 upstream.
    
    drivers/mtd/maps/ixp4xx.c requires MTD_CFI_BE_BYTE_SWAP to be set
    in order to compile.
    
    drivers/mtd/maps/ixp4xx.c:57:4: error: #error CONFIG_MTD_CFI_BE_BYTE_SWAP required
    
    This patch avoids the #error output by enforcing the policy in
    Kconfig. Not sure if this is the right approach, but it helps doing
    randconfig builds.
    
    Signed-off-by: Arnd Bergmann <arnd@arndb.de>
    Acked-by: Linus Walleij <linus.walleij@linaro.org>
    Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
    Link: https://lore.kernel.org/linux-mtd/20210927141045.1597593-1-arnd@kernel.org
    Cc: Anders Roxell <anders.roxell@linaro.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 
orangefs: Fix the size of a memory allocation in orangefs_bufmap_alloc() [+ + +]
Author: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Date:   Mon Dec 27 19:09:18 2021 +0100

    orangefs: Fix the size of a memory allocation in orangefs_bufmap_alloc()
    
    commit 40a74870b2d1d3d44e13b3b73c6571dd34f5614d upstream.
    
    'buffer_index_array' really looks like a bitmap. So it should be allocated
    as such.
    When kzalloc is called, a number of bytes is expected, but a number of
    longs is passed instead.
    
    In get(), if not enough memory is allocated, un-allocated memory may be
    read or written.
    
    So use bitmap_zalloc() to safely allocate the correct memory size and
    avoid un-expected behavior.
    
    While at it, change the corresponding kfree() into bitmap_free() to keep
    the semantic.
    
    Fixes: ea2c9c9f6574 ("orangefs: bufmap rewrite")
    Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
    Signed-off-by: Mike Marshall <hubcap@omnibond.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 
perf: Protect perf_guest_cbs with RCU [+ + +]
Author: Sean Christopherson <seanjc@google.com>
Date:   Thu Nov 11 02:07:22 2021 +0000

    perf: Protect perf_guest_cbs with RCU
    
    commit ff083a2d972f56bebfd82409ca62e5dfce950961 upstream.
    
    Protect perf_guest_cbs with RCU to fix multiple possible errors.  Luckily,
    all paths that read perf_guest_cbs already require RCU protection, e.g. to
    protect the callback chains, so only the direct perf_guest_cbs touchpoints
    need to be modified.
    
    Bug #1 is a simple lack of WRITE_ONCE/READ_ONCE behavior to ensure
    perf_guest_cbs isn't reloaded between a !NULL check and a dereference.
    Fixed via the READ_ONCE() in rcu_dereference().
    
    Bug #2 is that on weakly-ordered architectures, updates to the callbacks
    themselves are not guaranteed to be visible before the pointer is made
    visible to readers.  Fixed by the smp_store_release() in
    rcu_assign_pointer() when the new pointer is non-NULL.
    
    Bug #3 is that, because the callbacks are global, it's possible for
    readers to run in parallel with an unregisters, and thus a module
    implementing the callbacks can be unloaded while readers are in flight,
    resulting in a use-after-free.  Fixed by a synchronize_rcu() call when
    unregistering callbacks.
    
    Bug #1 escaped notice because it's extremely unlikely a compiler will
    reload perf_guest_cbs in this sequence.  perf_guest_cbs does get reloaded
    for future derefs, e.g. for ->is_user_mode(), but the ->is_in_guest()
    guard all but guarantees the consumer will win the race, e.g. to nullify
    perf_guest_cbs, KVM has to completely exit the guest and teardown down
    all VMs before KVM start its module unload / unregister sequence.  This
    also makes it all but impossible to encounter bug #3.
    
    Bug #2 has not been a problem because all architectures that register
    callbacks are strongly ordered and/or have a static set of callbacks.
    
    But with help, unloading kvm_intel can trigger bug #1 e.g. wrapping
    perf_guest_cbs with READ_ONCE in perf_misc_flags() while spamming
    kvm_intel module load/unload leads to:
    
      BUG: kernel NULL pointer dereference, address: 0000000000000000
      #PF: supervisor read access in kernel mode
      #PF: error_code(0x0000) - not-present page
      PGD 0 P4D 0
      Oops: 0000 [#1] PREEMPT SMP
      CPU: 6 PID: 1825 Comm: stress Not tainted 5.14.0-rc2+ #459
      Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
      RIP: 0010:perf_misc_flags+0x1c/0x70
      Call Trace:
       perf_prepare_sample+0x53/0x6b0
       perf_event_output_forward+0x67/0x160
       __perf_event_overflow+0x52/0xf0
       handle_pmi_common+0x207/0x300
       intel_pmu_handle_irq+0xcf/0x410
       perf_event_nmi_handler+0x28/0x50
       nmi_handle+0xc7/0x260
       default_do_nmi+0x6b/0x170
       exc_nmi+0x103/0x130
       asm_exc_nmi+0x76/0xbf
    
    Fixes: 39447b386c84 ("perf: Enhance perf to allow for guest statistic collection from host")
    Signed-off-by: Sean Christopherson <seanjc@google.com>
    Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
    Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
    Cc: stable@vger.kernel.org
    Link: https://lore.kernel.org/r/20211111020738.2512932-2-seanjc@google.com
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 
rtlwifi: rtl8192cu: Fix WARNING when calling local_irq_restore() with interrupts enabled [+ + +]
Author: Larry Finger <Larry.Finger@lwfinger.net>
Date:   Wed Dec 15 11:11:05 2021 -0600

    rtlwifi: rtl8192cu: Fix WARNING when calling local_irq_restore() with interrupts enabled
    
    commit 8b144dedb928e4e2f433a328d58f44c3c098d63e upstream.
    
    Syzbot reports the following WARNING:
    
    [200~raw_local_irq_restore() called with IRQs enabled
    WARNING: CPU: 1 PID: 1206 at kernel/locking/irqflag-debug.c:10
       warn_bogus_irq_restore+0x1d/0x20 kernel/locking/irqflag-debug.c:10
    
    Hardware initialization for the rtl8188cu can run for as long as 350 ms,
    and the routine may be called with interrupts disabled. To avoid locking
    the machine for this long, the current routine saves the interrupt flags
    and enables local interrupts. The problem is that it restores the flags
    at the end without disabling local interrupts first.
    
    This patch fixes commit a53268be0cb9 ("rtlwifi: rtl8192cu: Fix too long
    disable of IRQs").
    
    Reported-by: syzbot+cce1ee31614c171f5595@syzkaller.appspotmail.com
    Cc: stable@vger.kernel.org
    Fixes: a53268be0cb9 ("rtlwifi: rtl8192cu: Fix too long disable of IRQs")
    Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
    Signed-off-by: Kalle Valo <kvalo@kernel.org>
    Link: https://lore.kernel.org/r/20211215171105.20623-1-Larry.Finger@lwfinger.net
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

 
vfs: fs_context: fix up param length parsing in legacy_parse_param [+ + +]
Author: Jamie Hill-Daniel <jamie@hill-daniel.co.uk>
Date:   Tue Jan 18 08:06:04 2022 +0100

    vfs: fs_context: fix up param length parsing in legacy_parse_param
    
    commit 722d94847de29310e8aa03fcbdb41fc92c521756 upstream.
    
    The "PAGE_SIZE - 2 - size" calculation in legacy_parse_param() is an
    unsigned type so a large value of "size" results in a high positive
    value instead of a negative value as expected.  Fix this by getting rid
    of the subtraction.
    
    Signed-off-by: Jamie Hill-Daniel <jamie@hill-daniel.co.uk>
    Signed-off-by: William Liu <willsroot@protonmail.com>
    Tested-by: Salvatore Bonaccorso <carnil@debian.org>
    Tested-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
    Acked-by: Dan Carpenter <dan.carpenter@oracle.com>
    Acked-by: Al Viro <viro@zeniv.linux.org.uk>
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>