With LTO, everything is compiled into LLVM bitcode, so we have to link
each module into native code before modpost. Kbuild uses the .lto.o
suffix for these files, which also ends up in module information. This
change strips the unnecessary .lto suffix from the module name.
Suggested-by: Bill Wendling <morbo@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-11-samitolvanen@google.com

With Clang's Link Time Optimization (LTO), the compiler can rename
static functions to avoid global naming collisions. As PCI fixup
functions are typically static, renaming can break references
to them in inline assembly. This change adds a global stub to
DECLARE_PCI_FIXUP_SECTION to fix the issue when PREL32 relocations
are used.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-10-samitolvanen@google.com

With LTO, the compiler can rename static functions to avoid global
naming collisions. As initcall functions are typically static,
renaming can break references to them in inline assembly. This
change adds a global stub with a stable name for each initcall to
fix the issue when PREL32 relocations are used.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-9-samitolvanen@google.com

With LTO, the compiler doesn't necessarily obey the link order for
initcalls, and initcall variables need globally unique names to avoid
collisions at link time.

This change exports __KBUILD_MODNAME and adds the initcall_id() macro,
which uses it together with __COUNTER__ and __LINE__ to help ensure
these variables have unique names, and moves each variable to its own
section when LTO is enabled, so the correct order can be specified using
a linker script.

The generate_initcall_ordering.pl script uses nm to find initcalls from
the object files passed to the linker, and generates a linker script
that specifies the same order for initcalls that we would have without
LTO. With LTO enabled, the script is called in link-vmlinux.sh through
jobserver-exec to limit the number of jobs spawned.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-8-samitolvanen@google.com

With CONFIG_LTO_CLANG, LLVM bitcode has not yet been compiled into a
binary when the .mod files are generated, which means they don't yet
contain references to certain symbols that will be present in the final
binaries. This includes intrinsic functions, such as memcpy, memmove,
and memset [1], and stack protector symbols [2]. This change adds a
default symbol list to use with CONFIG_TRIM_UNUSED_KSYMS when Clang's
LTO is used.

[1] https://llvm.org/docs/LangRef.html#standard-c-c-library-intrinsics
[2] https://llvm.org/docs/LangRef.html#llvm-stackprotector-intrinsicSigned-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-7-samitolvanen@google.com

LLD always splits sections with LTO, which increases module sizes. This
change adds linker script rules to merge the split sections in the final
module.
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-6-samitolvanen@google.com

This change limits function inlining across translation unit boundaries
in order to reduce the binary size with LTO. The -import-instr-limit
flag defines a size limit, as the number of LLVM IR instructions, for
importing functions from other TUs, defaulting to 100.

Based on testing with arm64 defconfig, we found that a limit of 5 is a
reasonable compromise between performance and binary size, reducing the
size of a stripped vmlinux by 11%.
Suggested-by: George Burgess IV <gbiv@google.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-5-samitolvanen@google.com

With CONFIG_MODVERSIONS, version information is linked into each
compilation unit that exports symbols. With LTO, we cannot use this
method as all C code is compiled into LLVM bitcode instead. This
change collects symbol versions into .symversions files and merges
them in link-vmlinux.sh where they are all linked into vmlinux.o at
the same time.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-4-samitolvanen@google.com

This change adds build system support for Clang's Link Time
Optimization (LTO). With -flto, instead of ELF object files, Clang
produces LLVM bitcode, which is compiled into native code at link
time, allowing the final binary to be optimized globally. For more
details, see:

  https://llvm.org/docs/LinkTimeOptimization.html

The Kconfig option CONFIG_LTO_CLANG is implemented as a choice,
which defaults to LTO being disabled. To use LTO, the architecture
must select ARCH_SUPPORTS_LTO_CLANG and support:

  - compiling with Clang,
  - compiling all assembly code with Clang's integrated assembler,
  - and linking with LLD.

While using CONFIG_LTO_CLANG_FULL results in the best runtime
performance, the compilation is not scalable in time or
memory. CONFIG_LTO_CLANG_THIN enables ThinLTO, which allows
parallel optimization and faster incremental builds. ThinLTO is
used by default if the architecture also selects
ARCH_SUPPORTS_LTO_CLANG_THIN:

  https://clang.llvm.org/docs/ThinLTO.html

To enable LTO, LLVM tools must be used to handle bitcode files, by
passing LLVM=1 and LLVM_IAS=1 options to make:

  $ make LLVM=1 LLVM_IAS=1 defconfig
  $ scripts/config -e LTO_CLANG_THIN
  $ make LLVM=1 LLVM_IAS=1

To prepare for LTO support with other compilers, common parts are
gated behind the CONFIG_LTO option, and LTO can be disabled for
specific files by filtering out CC_FLAGS_LTO.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-3-samitolvanen@google.com

Move function tracer options to Kconfig to make it easier to add
new methods for generating __mcount_loc, and to make the options
available also when building kernel modules.

Note that FTRACE_MCOUNT_USE_* options are updated on rebuild and
therefore, work even if the .config was generated in a different
environment.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201211184633.3213045-2-samitolvanen@google.com

Pull s390 cleanups from Vasily Gorbik:
 "Update defconfigs and sort config select list"

* tag 's390-5.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/Kconfig: sort config S390 select list once again
  s390: update defconfigs

Pull power management fixes from Rafael Wysocki:
 "These fix a crash in intel_pstate during resume from suspend-to-RAM
  that may occur after recent changes and two resource leaks in error
  paths in the operating performance points (OPP) framework, add a new
  C-states table to intel_idle and update the cpuidle MAINTAINERS entry
  to cover the governors too.

  Specifics:

   - Fix recently introduced crash in the intel_pstate driver that
     occurs if scale-invariance is disabled during resume from
     suspend-to-RAM due to inconsistent changes of APERF or MPERF MSR
     values made by the platform firmware (Rafael Wysocki).

   - Fix a memory leak and add a missing clk_put() in error paths in the
     OPP framework (Quanyang Wang, Viresh Kumar).

   - Add new C-states table for SnowRidge processors to the intel_idle
     driver (Artem Bityutskiy).

   - Update the MAINTAINERS entry for cpuidle to make it clear that the
     governors are covered by it too (Lukas Bulwahn)"

* tag 'pm-5.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  intel_idle: add SnowRidge C-state table
  cpufreq: intel_pstate: Fix fast-switch fallback path
  opp: Call the missing clk_put() on error
  opp: fix memory leak in _allocate_opp_table
  MAINTAINERS: include governors into CPU IDLE TIME MANAGEMENT FRAMEWORK

* pm-cpufreq:
  cpufreq: intel_pstate: Fix fast-switch fallback path

* pm-cpuidle:
  intel_idle: add SnowRidge C-state table
  MAINTAINERS: include governors into CPU IDLE TIME MANAGEMENT FRAMEWORK

Pull SCSI fixes from James Bottomley:
 "This is a load of driver fixes (12 ufs, 1 mpt3sas, 1 cxgbi).

  The big core two fixes are for power management ("block: Do not accept
  any requests while suspended" and "block: Fix a race in the runtime
  power management code") which finally sorts out the resume problems
  we've occasionally been having.

  To make the resume fix, there are seven necessary precursors which
  effectively renames REQ_PREEMPT to REQ_PM, so every "special" request
  in block is automatically a power management exempt one.

  All of the non-PM preempt cases are removed except for the one in the
  SCSI Parallel Interface (spi) domain validation which is a genuine
  case where we have to run requests at high priority to validate the
  bus so this becomes an autopm get/put protected request"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (22 commits)
  scsi: cxgb4i: Fix TLS dependency
  scsi: ufs: Un-inline ufshcd_vops_device_reset function
  scsi: ufs: Re-enable WriteBooster after device reset
  scsi: ufs-mediatek: Use correct path to fix compile error
  scsi: mpt3sas: Signedness bug in _base_get_diag_triggers()
  scsi: block: Do not accept any requests while suspended
  scsi: block: Remove RQF_PREEMPT and BLK_MQ_REQ_PREEMPT
  scsi: core: Only process PM requests if rpm_status != RPM_ACTIVE
  scsi: scsi_transport_spi: Set RQF_PM for domain validation commands
  scsi: ide: Mark power management requests with RQF_PM instead of RQF_PREEMPT
  scsi: ide: Do not set the RQF_PREEMPT flag for sense requests
  scsi: block: Introduce BLK_MQ_REQ_PM
  scsi: block: Fix a race in the runtime power management code
  scsi: ufs-pci: Enable UFSHCD_CAP_RPM_AUTOSUSPEND for Intel controllers
  scsi: ufs-pci: Fix recovery from hibernate exit errors for Intel controllers
  scsi: ufs-pci: Ensure UFS device is in PowerDown mode for suspend-to-disk ->poweroff()
  scsi: ufs-pci: Fix restore from S4 for Intel controllers
  scsi: ufs-mediatek: Keep VCC always-on for specific devices
  scsi: ufs: Allow regulators being always-on
  scsi: ufs: Clear UAC for RPMB after ufshcd resets
  ...

Pull block fixes from Jens Axboe:
 "Two minor block fixes from this last week that should go into 5.11:

   - Add missing NOWAIT debugfs definition (Andres)

   - Fix kerneldoc warning introduced this merge window (Randy)"

* tag 'block-5.11-2021-01-01' of git://git.kernel.dk/linux-block:
  block: add debugfs stanza for QUEUE_FLAG_NOWAIT
  fs: block_dev.c: fix kernel-doc warnings from struct block_device changes

Pull io_uring fixes from Jens Axboe:
 "A few fixes that should go into 5.11, all marked for stable as well:

   - Fix issue around identity COW'ing and users that share a ring
     across processes

   - Fix a hang associated with unregistering fixed files (Pavel)

   - Move the 'process is exiting' cancelation a bit earlier, so
     task_works aren't affected by it (Pavel)"

* tag 'io_uring-5.11-2021-01-01' of git://git.kernel.dk/linux-block:
  kernel/io_uring: cancel io_uring before task works
  io_uring: fix io_sqe_files_unregister() hangs
  io_uring: add a helper for setting a ref node
  io_uring: don't assume mm is constant across submits

Commit 436e980e ("kbuild: don't hardcode depmod path") stopped
hard-coding the path of depmod, but in the process caused trouble for
distributions that had that /sbin location, but didn't have it in the
PATH (generally because /sbin is limited to the super-user path).

Work around it for now by just adding /sbin to the end of PATH in the
depmod.sh script.
Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

For cancelling io_uring requests it needs either to be able to run
currently enqueued task_works or having it shut down by that moment.
Otherwise io_uring_cancel_files() may be waiting for requests that won't
ever complete.

Go with the first way and do cancellations before setting PF_EXITING and
so before putting the task_work infrastructure into a transition state
where task_work_run() would better not be called.

Cc: stable@vger.kernel.org # 5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_sqe_files_unregister() uninterruptibly waits for enqueued ref nodes,
however requests keeping them may never complete, e.g. because of some
userspace dependency. Make sure it's interruptible otherwise it would
hang forever.

Cc: stable@vger.kernel.org # 5.6+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Setting a new reference node to a file data is not trivial, don't repeat
it, add and use a helper.

Cc: stable@vger.kernel.org # 5.6+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull ceph fixes from Ilya Dryomov:
 "A fix for an edge case in MClientRequest encoding and a couple of
  trivial fixups for the new msgr2 support"

* tag 'ceph-for-5.11-rc2' of git://github.com/ceph/ceph-client:
  libceph: add __maybe_unused to DEFINE_MSGR2_FEATURE
  libceph: align session_key and con_secret to 16 bytes
  libceph: fix auth_signature buffer allocation in secure mode
  ceph: reencode gid_list when reconnecting

Add C-state table for the SnowRidge SoC which is found on Intel Jacobsville
platforms.

The following has been changed.

 1. C1E latency changed from 10us to 15us. It was measured using the
    open source "wult" tool (the "nic" method, 15us is the 99.99th
    percentile).

 2. C1E power break even changed from 20us to 25us, which may result
    in less C1E residency in some workloads.

 3. C6 latency changed from 50us to 130us. Measured the same way as C1E.

The C6 C-state is supported only by some SnowRidge revisions, so add a C-state
table commentary about this.

On SnowRidge, C6 support is enumerated via the usual mechanism: "mwait" leaf of
the "cpuid" instruction. The 'intel_idle' driver does check this leaf, so even
though C6 is present in the table, the driver will only use it if the CPU does
support it.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

When sugov_update_single_perf() falls back to the "frequency"
path due to the missing scale-invariance, it will call
cpufreq_driver_fast_switch() via sugov_fast_switch()
and the driver's ->fast_switch() callback will be invoked,
so it must not be NULL.

However, after commit a365ab6b ("cpufreq: intel_pstate: Implement
the ->adjust_perf() callback") intel_pstate sets ->fast_switch() to
NULL when it is going to use intel_cpufreq_adjust_perf(), which is a
mistake, because on x86 the scale-invariance may be turned off
dynamically, so modify it to retain the original ->adjust_perf()
callback pointer.

Fixes: a365ab6b ("cpufreq: intel_pstate: Implement the ->adjust_perf() callback")
Reported-by: Kenneth R. Crudup <kenny@panix.com>
Tested-by: Kenneth R. Crudup <kenny@panix.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull operating performance points (OPP) framework fixes for 5.11-rc2
from Viresh Kumar:

"This contains two patches to fix freeing of resources in error paths."

* 'opp/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
  opp: Call the missing clk_put() on error
  opp: fix memory leak in _allocate_opp_table

...and add comments at the top and bottom.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

This was missed in 021a2446. Leads to the numeric value of
QUEUE_FLAG_NOWAIT (i.e. 29) showing up in
/sys/kernel/debug/block/*/state.

Fixes: 021a2446
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Fix new kernel-doc warnings in fs/block_dev.c:

../fs/block_dev.c:1066: warning: Excess function parameter 'whole' description in 'bd_abort_claiming'
../fs/block_dev.c:1837: warning: Function parameter or member 'dev' not described in 'lookup_bdev'

Fixes: 4e7b5671 ("block: remove i_bdev")
Fixes: 37c3fc9a ("block: simplify the block device claiming interface")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-fsdevel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Merge misc fixes from Andrew Morton:
 "16 patches

  Subsystems affected by this patch series: mm (selftests, hugetlb,
  pagecache, mremap, kasan, and slub), kbuild, checkpatch, misc, and
  lib"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: slub: call account_slab_page() after slab page initialization
  zlib: move EXPORT_SYMBOL() and MODULE_LICENSE() out of dfltcc_syms.c
  lib/zlib: fix inflating zlib streams on s390
  lib/genalloc: fix the overflow when size is too big
  kdev_t: always inline major/minor helper functions
  sizes.h: add SZ_8G/SZ_16G/SZ_32G macros
  local64.h: make <asm/local64.h> mandatory
  kasan: fix null pointer dereference in kasan_record_aux_stack
  mm: generalise COW SMC TLB flushing race comment
  mm/mremap.c: fix extent calculation
  mm: memmap defer init doesn't work as expected
  mm: add prototype for __add_to_page_cache_locked()
  checkpatch: prefer strscpy to strlcpy
  Revert "kbuild: avoid static_assert for genksyms"
  mm/hugetlb: fix deadlock in hugetlb_cow error path
  selftests/vm: fix building protection keys test

It's convenient to have page->objects initialized before calling into
account_slab_page().  In particular, this information can be used to
pre-alloc the obj_cgroup vector.

Let's call account_slab_page() a bit later, after the initialization of
page->objects.

This commit doesn't bring any functional change, but is required for
further optimizations.

[akpm@linux-foundation.org: undo changes needed by forthcoming mm-memcg-slab-pre-allocate-obj_cgroups-for-slab-caches-with-slab_account.patch]

Link: https://lkml.kernel.org/r/20201110195753.530157-1-guro@fb.comSigned-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In commit 11fb479f ("zlib: export S390 symbols for zlib modules"), I
added EXPORT_SYMBOL()s to dfltcc_inflate.c but then Mikhail said that
these should probably be in dfltcc_syms.c with the other
EXPORT_SYMBOL()s.

However, that is contrary to the current kernel style, which places
EXPORT_SYMBOL() immediately after the function that it applies to, so
move all EXPORT_SYMBOL()s to their respective function locations and
drop the dfltcc_syms.c file.  Also move MODULE_LICENSE() from the
deleted file to dfltcc.c.

[rdunlap@infradead.org: remove dfltcc_syms.o from Makefile]
  Link: https://lkml.kernel.org/r/20201227171837.15492-1-rdunlap@infradead.org

Link: https://lkml.kernel.org/r/20201219052530.28461-1-rdunlap@infradead.org
Fixes: 11fb479f ("zlib: export S390 symbols for zlib modules")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Zaslonko Mikhail <zaslonko@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Decompressing zlib streams on s390 fails with "incorrect data check"
error.

Userspace zlib checks inflate_state.flags in order to byteswap checksums
only for zlib streams, and s390 hardware inflate code, which was ported
from there, tries to match this behavior.  At the same time, kernel zlib
does not use inflate_state.flags, so it contains essentially random
values.  For many use cases either zlib stream is zeroed out or checksum
is not used, so this problem is masked, but at least SquashFS is still
affected.

Fix by always passing a checksum to and from the hardware as is, which
matches zlib_inflate()'s expectations.

Link: https://lkml.kernel.org/r/20201215155551.894884-1-iii@linux.ibm.com
Fixes: 12619610 ("lib/zlib: add s390 hardware support for kernel zlib_inflate")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Cc: <stable@vger.kernel.org>	[5.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Some graphic card has very big memory on chip, such as 32G bytes.

In the following case, it will cause overflow:

    pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
    ret = gen_pool_add(pool, 0x1000000, SZ_32G, NUMA_NO_NODE);

    va = gen_pool_alloc(pool, SZ_4G);

The overflow occurs in gen_pool_alloc_algo_owner():

		....
		size = nbits << order;
		....

The @nbits is "int" type, so it will overflow.
Then the gen_pool_avail() will return the wrong value.

This patch converts some "int" to "unsigned long", and
changes the compare code in while.

Link: https://lkml.kernel.org/r/20201229060657.3389-1-sjhuang@iluvatar.aiSigned-off-by: Huang Shijie <sjhuang@iluvatar.ai>
Reported-by: Shi Jiasheng <jiasheng.shi@iluvatar.ai>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Silly GCC doesn't always inline these trivial functions.

Fixes the following warning:

  arch/x86/kernel/sys_ia32.o: warning: objtool: cp_stat64()+0xd8: call to new_encode_dev() with UACCESS enabled

Link: https://lkml.kernel.org/r/984353b44a4484d86ba9f73884b7306232e25e30.1608737428.git.jpoimboe@redhat.comSigned-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>	[build-tested]
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add these macros, since we can use them in drivers.

Link: https://lkml.kernel.org/r/20201229072819.11183-1-sjhuang@iluvatar.aiSigned-off-by: Huang Shijie <sjhuang@iluvatar.ai>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Make <asm-generic/local64.h> mandatory in include/asm-generic/Kbuild and
remove all arch/*/include/asm/local64.h arch-specific files since they
only #include <asm-generic/local64.h>.

This fixes build errors on arch/c6x/ and arch/nios2/ for
block/blk-iocost.c.

Build-tested on 21 of 25 arch-es.  (tools problems on the others)

Yes, we could even rename <asm-generic/local64.h> to
<linux/local64.h> and change all #includes to use
<linux/local64.h> instead.

Link: https://lkml.kernel.org/r/20201227024446.17018-1-rdunlap@infradead.orgSigned-off-by: Randy Dunlap <rdunlap@infradead.org>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <jacquiot.aurelien@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Syzbot reported the following [1]:

  BUG: kernel NULL pointer dereference, address: 0000000000000008
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 2d993067 P4D 2d993067 PUD 19a3c067 PMD 0
  Oops: 0000 [#1] PREEMPT SMP KASAN
  CPU: 1 PID: 3852 Comm: kworker/1:2 Not tainted 5.10.0-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  Workqueue: events free_ipc
  RIP: 0010:kasan_record_aux_stack+0x77/0xb0

Add null checking slab object from kasan_get_alloc_meta() in order to
avoid null pointer dereference.

[1] https://syzkaller.appspot.com/x/log.txt?x=10a82a50d00000

Link: https://lkml.kernel.org/r/20201228080018.23041-1-walter-zh.wu@mediatek.comSigned-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

I'm not sure if I'm completely missing something here, but AFAIKS the
reference to the mysterious "COW SMC race" confuses the issue.  The
original changelog and mailing list thread didn't help me either.

This SMC race is where the problem was detected, but isn't the general
problem bigger and more obvious: that the new PTE could be picked up at
any time by any TLB while entries for the old PTE exist in other TLBs
before the TLB flush takes effect?

The case where the iTLB and dTLB of a CPU are pointing at different pages
is an interesting one but follows from the general problem.

The other (minor) thing with the comment I think it makes it a bit clearer
to say what the old code was doing (i.e., it avoids the race as opposed to
what?).

References: 4ce072f1 ("mm: fix a race condition under SMC + COW")
Link: https://lkml.kernel.org/r/20201215121119.351650-1-npiggin@gmail.comReviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When `next < old_addr`, `next - old_addr` arithmetic underflows causing
`extent` to be incorrect.

Make `extent` the smaller of `next - old_addr` or `old_end - old_addr`.

Link: https://lkml.kernel.org/r/20201219170433.2418867-1-kaleshsingh@google.com
Fixes: c49dd340 ("mm: speedup mremap on 1GB or larger regions")
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>