Pull locking fix from Borislav Petkov:

 - Avoid rwsem lockups in certain situations when handling the handoff
   bit

* tag 'locking_urgent_for_v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/rwsem: Allow slowpath writer to ignore handoff bit if not set by first waiter

Pull EDAC fixes from Borislav Petkov:

 - Relax the condition under which the DIMM label in ghes_edac is set in
   order to accomodate an HPE BIOS which sets only the device but not
   the bank

 - Two forgotten fixes to synopsys_edac when handling error interrupts

* tag 'edac_urgent_for_v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
  EDAC/ghes: Set the DIMM label unconditionally
  EDAC/synopsys: Re-enable the error interrupts on v3 hw
  EDAC/synopsys: Use the correct register to disable the error interrupt on v3 hw

Pull ARM fixes from Russell King:
 "Last set of ARM fixes for 5.19:

   - fix for MAX_DMA_ADDRESS overflow

   - fix for find_*_bit performing an out of bounds memory access"

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: findbit: fix overflowing offset
  ARM: 9216/1: Fix MAX_DMA_ADDRESS overflow

With commit d257cc8c ("locking/rwsem: Make handoff bit handling more
consistent"), the writer that sets the handoff bit can be interrupted
out without clearing the bit if the wait queue isn't empty. This disables
reader and writer optimistic lock spinning and stealing.

Now if a non-first writer in the queue is somehow woken up or a new
waiter enters the slowpath, it can't acquire the lock.  This is not the
case before commit d257cc8c as the writer that set the handoff bit
will clear it when exiting out via the out_nolock path. This is less
efficient as the busy rwsem stays in an unlock state for a longer time.

In some cases, this new behavior may cause lockups as shown in [1] and
[2].

This patch allows a non-first writer to ignore the handoff bit if it
is not originally set or initiated by the first waiter. This patch is
shown to be effective in fixing the lockup problem reported in [1].

[1] https://lore.kernel.org/lkml/20220617134325.GC30825@techsingularity.net/
[2] https://lore.kernel.org/lkml/3f02975c-1a9d-be20-32cf-f1d8e3dfafcc@oracle.com/

Fixes: d257cc8c ("locking/rwsem: Make handoff bit handling more consistent")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Donnelly <john.p.donnelly@oracle.com>
Tested-by: Mel Gorman <mgorman@techsingularity.net>
Link: https://lore.kernel.org/r/20220622200419.778799-1-longman@redhat.com

Pull misc fixes from Andrew Morton:
 "Two hotfixes, both cc:stable"

* tag 'mm-hotfixes-stable-2022-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/hmm: fault non-owner device private entries
  page_alloc: fix invalid watermark check on a negative value

Pull block fix from Jens Axboe:
 "Just a single fix for NVMe, yet another quirk addition"

* tag 'block-5.19-2022-07-29' of git://git.kernel.dk/linux-block:
  nvme-pci: Crucial P2 has bogus namespace ids

Pull more drm fixes from Dave Airlie:
 "Maxime had the dog^Wmailing list server eat his homework^Wmisc pull
  request.

  Two more small fixes, one in nouveau svm code and the other in
  simpledrm.

  nouveau:
   - page migration fix

  simpledrm:
   - fix mode_valid return value"

* tag 'drm-fixes-2022-07-30' of git://anongit.freedesktop.org/drm/drm:
  nouveau/svm: Fix to migrate all requested pages
  drm/simpledrm: Fix return type of simpledrm_simple_display_pipe_mode_valid()

One fix to fix simpledrm mode_valid return value, and one for page
migration in nouveau
Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220729094514.sfzhc3gqjgwgal62@penduick

Pull SCSI fixes from James Bottomley:
 "Four fixes, three in drivers.

  The two biggest fixes are ufs and the remaining driver and core fix
  are small and obvious (and the core fix is low risk)"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: ufs: core: Fix a race condition related to device management
  scsi: core: Fix warning in scsi_alloc_sgtables()
  scsi: ufs: host: Hold reference returned by of_parse_phandle()
  scsi: mpt3sas: Stop fw fault watchdog work item during system shutdown

If hmm_range_fault() is called with the HMM_PFN_REQ_FAULT flag and a
device private PTE is found, the hmm_range::dev_private_owner page is used
to determine if the device private page should not be faulted in. 
However, if the device private page is not owned by the caller,
hmm_range_fault() returns an error instead of calling migrate_to_ram() to
fault in the page.

For example, if a page is migrated to GPU private memory and a RDMA fault
capable NIC tries to read the migrated page, without this patch it will
get an error.  With this patch, the page will be migrated back to system
memory and the NIC will be able to read the data.

Link: https://lkml.kernel.org/r/20220727000837.4128709-2-rcampbell@nvidia.com
Link: https://lkml.kernel.org/r/20220725183615.4118795-2-rcampbell@nvidia.com
Fixes: 08ddddda ("mm/hmm: check the device private page owner in hmm_range_fault()")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reported-by: Felix Kuehling <felix.kuehling@amd.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Philip Yang <Philip.Yang@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

There was a report that a task is waiting at the
throttle_direct_reclaim. The pgscan_direct_throttle in vmstat was
increasing.

This is a bug where zone_watermark_fast returns true even when the free
is very low. The commit f27ce0e1 ("page_alloc: consider highatomic
reserve in watermark fast") changed the watermark fast to consider
highatomic reserve. But it did not handle a negative value case which
can be happened when reserved_highatomic pageblock is bigger than the
actual free.

If watermark is considered as ok for the negative value, allocating
contexts for order-0 will consume all free pages without direct reclaim,
and finally free page may become depleted except highatomic free.

Then allocating contexts may fall into throttle_direct_reclaim. This
symptom may easily happen in a system where wmark min is low and other
reclaimers like kswapd does not make free pages quickly.

Handle the negative case by using MIN.

Link: https://lkml.kernel.org/r/20220725095212.25388-1-jaewon31.kim@samsung.com
Fixes: f27ce0e1 ("page_alloc: consider highatomic reserve in watermark fast")
Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
Reported-by: GyeongHwan Hong <gh21.hong@samsung.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yong-Taek Lee <ytk.lee@samsung.com>
Cc: <stable@vger.kerenl.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Merge tag 'perf-tools-fixes-for-v5.19-2022-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux

Pull perf tools fixes from Arnaldo Carvalho de Melo:

 - Fix addresses for bss symbols, describing variables used in resolving
   data access in tools such as 'perf c2c' and 'perf mem'.

 - Skip symbols if SHF_ALLOC flag is not set, a technique used for
   listing deprecated symbols, its addresses are zeros, so not useful.

 - Remove undefined behavior from bpf_perf_object__next() when dealing
   with an empty bpf_objects_list list.

 - Make a ARM CoreSight disasm script work with both python2 and
   python3.

 - Sync x86's cpufeatures header with with the kernel sources.

* tag 'perf-tools-fixes-for-v5.19-2022-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
  perf bpf: Remove undefined behavior from bpf_perf_object__next()
  perf symbol: Skip symbols if SHF_ALLOC flag is not set
  perf symbol: Correct address for bss symbols
  perf scripts python: Let script to be python2 compliant
  tools headers cpufeatures: Sync with the kernel sources

Pull workqueue fix from Tejun Heo:
 "Just one commit to suppress a spurious warning added during the 5.19
  cycle"

* tag 'wq-for-5.19-rc8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Avoid a false warning in unbind_workers()

Pull power management fix from Rafael Wysocki:
 "Make some false positive RCU splats resulting from a recent intel_idle
  driver change go away (Waiman Long)"

* tag 'pm-5.19-rc9' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  intel_idle: Fix false positive RCU splats due to incorrect hardirqs state

Doing set_cpus_allowed_ptr() with wq_unbound_cpumask can be possible
fails and trigger the false warning.

Use cpu_possible_mask instead when wq_unbound_cpumask has no active CPUs.

It is very easy to trigger the warning:
  Set wq_unbound_cpumask to a small set of CPUs.
  Offline all the CPUs of wq_unbound_cpumask.
  Offline an extra CPU and trigger the warning.

Fixes: 10a5a651 ("workqueue: Restrict kworker in the offline CPU pool running on housekeeping CPUs")
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Pull RISC-V fix from Palmer Dabbelt:
 "A build fix for 'make vdso_install' that avoids an issue trying to
  install the compat VDSO"

* tag 'riscv-for-linus-5.19-rc9' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: compat: vdso: Fix vdso_install target

Merge tag 'loongarch-fixes-5.19-5' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch fixes from Huacai Chen:

 - Fix cache size calculation, stack protection attributes, ptrace's
   fpr_set and "ROM Size" in boardinfo

 - Some cleanups and improvements of assembly

 - Some cleanups of unused code and useless code

* tag 'loongarch-fixes-5.19-5' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
  LoongArch: Fix wrong "ROM Size" of boardinfo
  LoongArch: Fix missing fcsr in ptrace's fpr_set
  LoongArch: Fix shared cache size calculation
  LoongArch: Disable executable stack by default
  LoongArch: Remove unused variables
  LoongArch: Remove clock setting during cpu hotplug stage
  LoongArch: Remove useless header compiler.h
  LoongArch: Remove several syntactic sugar macros for branches
  LoongArch: Re-tab the assembly files
  LoongArch: Simplify "BGT foo, zero" with BGTZ
  LoongArch: Simplify "BLT foo, zero" with BLTZ
  LoongArch: Simplify "BEQ/BNE foo, zero" with BEQZ/BNEZ
  LoongArch: Use the "move" pseudo-instruction where applicable
  LoongArch: Use the "jr" pseudo-instruction where applicable
  LoongArch: Use ABI names of registers where appropriate

Pull powerpc fixes from Michael Ellerman:

 - Re-enable the new amdgpu display engine for powerpc, as long as the
   compiler is correctly configured.

 - Disable stack variable initialisation in prom_init to fix GCC 12
   allmodconfig.

Thanks to Dan Horák and Sudip Mukherjee.

* tag 'powerpc-5.19-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  drm/amdgpu: Re-enable DCN for 64-bit powerpc
  powerpc/64s: Disable stack variable initialisation for prom_init

We can see the "ROM Size" is different in the following outputs:

[root@linux loongson]# cat /sys/firmware/loongson/boardinfo
BIOS Information
Vendor                  : Loongson
Version                 : vUDK2018-LoongArch-V2.0.pre-beta8
ROM Size                : 63 KB
Release Date            : 06/15/2022

Board Information
Manufacturer            : Loongson
Board Name              : Loongson-LS3A5000-7A1000-1w-A2101
Family                  : LOONGSON64

[root@linux loongson]# dmidecode | head -11
...
Handle 0x0000, DMI type 0, 26 bytes
BIOS Information
	Vendor: Loongson
	Version: vUDK2018-LoongArch-V2.0.pre-beta8
	Release Date: 06/15/2022
	ROM Size: 4 MB

According to "BIOS Information (Type 0) structure" in the SMBIOS
Reference Specification [1], it shows 64K * (n+1) is the size of
the physical device containing the BIOS if the size is less than
16M.

Additionally, we can see the related code in dmidecode [2]:

  u64 s = { .l = (code1 + 1) << 6 };

So the output of dmidecode is correct, the output of boardinfo
is wrong, fix it.

By the way, at present no need to consider the size is 16M or
greater on LoongArch, because it is usually 4M or 8M which is
enough to use.

[1] https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_3.6.0.pdf
[2] https://git.savannah.nongnu.org/cgit/dmidecode.git/tree/dmidecode.c#n347

Fixes: 628c3bb4 ("LoongArch: Add boot and setup routines")
Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

In file ptrace.c, function fpr_set does not copy fcsr data from ubuf
to kbuf. That's the reason why fcsr cannot be modified by ptrace.

This patch fixs this problem and allows users using ptrace to modify
the fcsr.
Co-developed-by: Xu Li <lixu@loongson.cn>
Signed-off-by: Qi Hu <huqi@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Current calculation of shared cache size is from the node (die) scope,
but we hope 'lscpu' to show the shared cache size of the whole package
for multi-die chips (e.g., Loongson-3C5000L, which contains 4 dies in
one package). So fix it by multiplying nodes_per_package.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Disable executable stack for LoongArch by default, as all modern
architectures do.
Reported-by: Andreas Schwab <schwab@suse.de>
Suggested-by: WANG Xuerui <git@xen0n.name>
Link: https://sourceware.org/pipermail/binutils/2022-July/121992.htmlTested-by: WANG Xuerui <git@xen0n.name>
Tested-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

There are some variables never used or referenced, this patch
removes these varaibles and make the code cleaner.
Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

On physical machine we can save power by disabling clock of hot removed
cpu. However as different platforms require different methods to
configure clocks, the code is platform-specific, and probably belongs to
firmware/pmu or cpu regulator, rather than generic arch/loongarch code.

Also, there is no such register on QEMU virt machine since the
clock/frequency regulation is not emulated.

This patch removes the hard-coded clock register accesses in generic
LoongArch cpu hotplug flow.
Reviewed-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

The content of LoongArch's compiler.h is trivial, with some unused
anywhere, so inline the definitions and remove the header.
Signed-off-by: Jun Yi <yijun@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

These syntactic sugars have been supported by upstream binutils from the
beginning, so no need to patch them locally.
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Reflow the *.S files for better stylistic consistency, namely hard tabs
after mnemonic position, and vertical alignment of the first operand
with hard tabs. Tab width is obviously 8. Some pre-existing intra-block
vertical alignments are preserved.
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Support for the syntactic sugar is present in upstream binutils port
from the beginning. Use it for shorter lines and better consistency.
Generated code should be identical.
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Support for the syntactic sugar is present in upstream binutils port
from the beginning. Use it for shorter lines and better consistency.
Generated code should be identical.
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

While B{EQ,NE}Z and B{EQ,NE} are different instructions, and the vastly
expanded range for branch destination does not really matter in the few
cases touched, use the B{EQ,NE}Z where possible for shorter lines and
better consistency (e.g. some places used "BEQ foo, zero", while some
used "BEQ zero, foo").
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Some of the assembly code in the LoongArch port likely originated
from a time when the assembler did not support pseudo-instructions like
"move" or "jr", so the desugared form was used and readability suffers
(to a minor degree) as a result.

As the upstream toolchain supports these pseudo-instructions from the
beginning, migrate the existing few usages to them for better
readability.
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Some of the assembly code in the LoongArch port likely originated
from a time when the assembler did not support pseudo-instructions like
"move" or "jr", so the desugared form was used and readability suffers
(to a minor degree) as a result.

As the upstream toolchain supports these pseudo-instructions from the
beginning, migrate the existing few usages to them for better
readability.
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Some of the assembly in the LoongArch port seem to come from a
prehistoric time, when the assembler didn't even have support for the
ABI names we all come to know and love, thus used raw register numbers
which hampered readability.

The usages are found with a regex match inside arch/loongarch, then
manually adjusted for those non-definitions.
Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

When offset is larger than the size of the bit array, we should not
attempt to access the array as we can perform an access beyond the
end of the array. Fix this by changing the pre-condition.

Using "cmp r2, r1; bhs ..." covers us for the size == 0 case, since
this will always take the branch when r1 is zero, irrespective of
the value of r2. This means we can fix this bug without adding any
additional code!
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Pull drm fix from Dave Airlie:
 "Quiet extra week, just a single fix for i915 workaround with execlist
  backend.

  i915:

   - Further reset robustness improvements for execlists [Wa_22011802037]"

* tag 'drm-fixes-2022-07-29' of git://anongit.freedesktop.org/drm/drm:
  drm/i915/reset: Add additional steps for Wa_22011802037 for execlist backend

Merge tag 'drm-intel-fixes-2022-07-28-1' of git://anongit.freedesktop.org/drm/drm-intel into drm-fixes

- Further reset robustness improvements for execlists [Wa_22011802037] (Umesh Nerlige Ramappa)
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/YuJIWaEbKcs/q0NY@tursulin-desk

Users may request that pages from an OpenCL SVM allocation be migrated
to the GPU with clEnqueueSVMMigrateMem(). In Nouveau this will call into
nouveau_dmem_migrate_vma() to do the migration. If the total range to be
migrated exceeds SG_MAX_SINGLE_ALLOC the pages will be migrated in
chunks of size SG_MAX_SINGLE_ALLOC. However a typo in updating the
starting address means that only the first chunk will get migrated.

Fix the calculation so that the entire range will get migrated if
possible.
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Fixes: e3d8b089 ("drm/nouveau/svm: map pages after migration")
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220720062745.960701-1-apopple@nvidia.com
Cc: <stable@vger.kernel.org> # v5.8+

Pull networking fixes from Jakub Kicinski:
 "Including fixes from bluetooth and netfilter, no known blockers for
  the release.

  Current release - regressions:

   - wifi: mac80211: do not abuse fq.lock in ieee80211_do_stop(), fix
     taking the lock before its initialized

   - Bluetooth: mgmt: fix double free on error path

  Current release - new code bugs:

   - eth: ice: fix tunnel checksum offload with fragmented traffic

  Previous releases - regressions:

   - tcp: md5: fix IPv4-mapped support after refactoring, don't take the
     pure v6 path

   - Revert "tcp: change pingpong threshold to 3", improving detection
     of interactive sessions

   - mld: fix netdev refcount leak in mld_{query | report}_work() due to
     a race

   - Bluetooth:
      - always set event mask on suspend, avoid early wake ups
      - L2CAP: fix use-after-free caused by l2cap_chan_put

   - bridge: do not send empty IFLA_AF_SPEC attribute

  Previous releases - always broken:

   - ping6: fix memleak in ipv6_renew_options()

   - sctp: prevent null-deref caused by over-eager error paths

   - virtio-net: fix the race between refill work and close, resulting
     in NAPI scheduled after close and a BUG()

   - macsec:
      - fix three netlink parsing bugs
      - avoid breaking the device state on invalid change requests
      - fix a memleak in another error path

  Misc:

   - dt-bindings: net: ethernet-controller: rework 'fixed-link' schema

   - two more batches of sysctl data race adornment"

* tag 'net-5.19-final' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (67 commits)
  stmmac: dwmac-mediatek: fix resource leak in probe
  ipv6/addrconf: fix a null-ptr-deref bug for ip6_ptr
  net: ping6: Fix memleak in ipv6_renew_options().
  net/funeth: Fix fun_xdp_tx() and XDP packet reclaim
  sctp: leave the err path free in sctp_stream_init to sctp_stream_free
  sfc: disable softirqs for ptp TX
  ptp: ocp: Select CRC16 in the Kconfig.
  tcp: md5: fix IPv4-mapped support
  virtio-net: fix the race between refill work and close
  mptcp: Do not return EINPROGRESS when subflow creation succeeds
  Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put
  Bluetooth: Always set event mask on suspend
  Bluetooth: mgmt: Fix double free on error path
  wifi: mac80211: do not abuse fq.lock in ieee80211_do_stop()
  ice: do not setup vlan for loopback VSI
  ice: check (DD | EOF) bits on Rx descriptor rather than (EOP | RS)
  ice: Fix VSIs unable to share unicast MAC
  ice: Fix tunnel checksum offload with fragmented traffic
  ice: Fix max VLANs available for VF
  netfilter: nft_queue: only allow supported familes and hooks
  ...

If mediatek_dwmac_clks_config() fails, then call stmmac_remove_config_dt()
before returning.  Otherwise it is a resource leak.

Fixes: fa4b3ca6 ("stmmac: dwmac-mediatek: fix clock issue")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YuJ4aZyMUlG6yGGa@kiliSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Change net device's MTU to smaller than IPV6_MIN_MTU or unregister
device while matching route. That may trigger null-ptr-deref bug
for ip6_ptr probability as following.

=========================================================
BUG: KASAN: null-ptr-deref in find_match.part.0+0x70/0x134
Read of size 4 at addr 0000000000000308 by task ping6/263

CPU: 2 PID: 263 Comm: ping6 Not tainted 5.19.0-rc7+ #14
Call trace:
 dump_backtrace+0x1a8/0x230
 show_stack+0x20/0x70
 dump_stack_lvl+0x68/0x84
 print_report+0xc4/0x120
 kasan_report+0x84/0x120
 __asan_load4+0x94/0xd0
 find_match.part.0+0x70/0x134
 __find_rr_leaf+0x408/0x470
 fib6_table_lookup+0x264/0x540
 ip6_pol_route+0xf4/0x260
 ip6_pol_route_output+0x58/0x70
 fib6_rule_lookup+0x1a8/0x330
 ip6_route_output_flags_noref+0xd8/0x1a0
 ip6_route_output_flags+0x58/0x160
 ip6_dst_lookup_tail+0x5b4/0x85c
 ip6_dst_lookup_flow+0x98/0x120
 rawv6_sendmsg+0x49c/0xc70
 inet_sendmsg+0x68/0x94

Reproducer as following:
Firstly, prepare conditions:
$ip netns add ns1
$ip netns add ns2
$ip link add veth1 type veth peer name veth2
$ip link set veth1 netns ns1
$ip link set veth2 netns ns2
$ip netns exec ns1 ip -6 addr add 2001:0db8:0:f101::1/64 dev veth1
$ip netns exec ns2 ip -6 addr add 2001:0db8:0:f101::2/64 dev veth2
$ip netns exec ns1 ifconfig veth1 up
$ip netns exec ns2 ifconfig veth2 up
$ip netns exec ns1 ip -6 route add 2000::/64 dev veth1 metric 1
$ip netns exec ns2 ip -6 route add 2001::/64 dev veth2 metric 1

Secondly, execute the following two commands in two ssh windows
respectively:
$ip netns exec ns1 sh
$while true; do ip -6 addr add 2001:0db8:0:f101::1/64 dev veth1; ip -6 route add 2000::/64 dev veth1 metric 1; ping6 2000::2; done

$ip netns exec ns1 sh
$while true; do ip link set veth1 mtu 1000; ip link set veth1 mtu 1500; sleep 5; done

It is because ip6_ptr has been assigned to NULL in addrconf_ifdown() firstly,
then ip6_ignore_linkdown() accesses ip6_ptr directly without NULL check.

	cpu0			cpu1
fib6_table_lookup
__find_rr_leaf
			addrconf_notify [ NETDEV_CHANGEMTU ]
			addrconf_ifdown
			RCU_INIT_POINTER(dev->ip6_ptr, NULL)
find_match
ip6_ignore_linkdown

So we can add NULL check for ip6_ptr before using in ip6_ignore_linkdown() to
fix the null-ptr-deref bug.

Fixes: dcd1f572 ("net/ipv6: Remove fib6_idev")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220728013307.656257-1-william.xuanziyang@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>