In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memset(), avoid intentionally writing across
neighboring fields.

Add struct_group() to mark the "info" region (containing struct DInfo
and struct DXInfo structs) in struct hfsplus_cat_folder and struct
hfsplus_cat_file that are written into directly, so the compiler can
correctly reason about the expected size of the writes.

"pahole" shows no size nor member offset changes to struct
hfsplus_cat_folder nor struct hfsplus_cat_file.  "objdump -d" shows no
object code changes.

Link: https://lkml.kernel.org/r/20211119192851.1046717-1-keescook@chromium.orgSigned-off-by: NKees Cook <keescook@chromium.org>
Acked-by: NChristian Brauner <christian.brauner@ubuntu.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pointer sbufs is being assigned a value but it's not being used later
on.  The pointer is redundant and can be removed.  Cleans up scan-build
static analysis warning:

  fs/nilfs2/page.c:203:8: warning: Although the value stored to 'sbufs'
    is used in the enclosing expression, the value is never actually read
    from 'sbufs' [deadcode.DeadStores]
        sbh = sbufs = page_buffers(src);

Link: https://lkml.kernel.org/r/20211211180955.550380-1-colin.i.king@gmail.com
Link: https://lkml.kernel.org/r/1640712476-15136-1-git-send-email-konishi.ryusuke@gmail.comSigned-off-by: NColin Ian King <colin.i.king@gmail.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Extend commit ce81bb25 ("fs/binfmt_elf: use PT_LOAD p_align values
for suitable start address") which fixed PIE binaries built with
-Wl,-z,max-page-size=0x200000, to cover static PIE binaries.  This
fixes:

    https://bugzilla.kernel.org/show_bug.cgi?id=215275

Tested by verifying static PIE binaries with -Wl,-z,max-page-size=0x200000 loading.

Link: https://lkml.kernel.org/r/20211209174052.370537-1-hjl.tools@gmail.comSigned-off-by: NH.J. Lu <hjl.tools@gmail.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sandeep Patil <sspatil@google.com>
Cc: Fangrui Song <maskray@google.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add commonly used structs (>50 instances) which are always or almost
always const.

Link: https://lkml.kernel.org/r/20211127101134.33101-1-rikard.falkeborn@gmail.comSigned-off-by: NRikard Falkeborn <rikard.falkeborn@gmail.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The Kconfig help test erroneously counts patch context lines as part of
the help text.

Fix that and improve the message block output.

Link: https://lkml.kernel.org/r/06c0cdc157ae1502e8e9eb3624b9ea995cf11e7a.camel@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

One exceptions to the COMMIT_LOG_LONG_LINE rule is a file path followed
by ':'.  That is typically some sort diagnostic message from a compiler
or a build tool, in which case we don't want to wrap the lines but keep
the message unmodified.

The regular expression used to match this pattern currently doesn't
accept absolute paths or + characters.  This can result in false
positives as in the following (out-of-tree) example:

  ...
  /home/jerome/work/optee_repo_qemu/build/../toolchains/aarch32/bin/arm-linux-gnueabihf-ld.bfd: /home/jerome/work/toolchains-gcc10.2/aarch32/bin/../lib/gcc/arm-none-linux-gnueabihf/10.2.1/../../../../arm-none-linux-gnueabihf/lib/libstdc++.a(eh_alloc.o): in function `__cxa_allocate_exception':
  /tmp/dgboter/bbs/build03--cen7x86_64/buildbot/cen7x86_64--arm-none-linux-gnueabihf/build/src/gcc/libstdc++-v3/libsupc++/eh_alloc.cc:284: undefined reference to `malloc'
  ...

Update the regular expression to match the above paths.

Link: https://lkml.kernel.org/r/20210923143842.2837983-1-jerome@forissier.orgSigned-off-by: NJerome Forissier <jerome@forissier.org>
Acked-by: NJoe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make do_kmem_cache_size_bulk() destroy the cache it creates.

Link: https://lkml.kernel.org/r/aced20a94bf04159a139f0846e41d38a1537debb.1640018297.git.andreyknvl@google.com
Fixes: 03a9349a ("lib/test_meminit: add a kmem_cache_alloc_bulk() test")
Signed-off-by: NAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: NMarco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove licence boilerplate text from the UAPI header.

Link: https://lkml.kernel.org/r/20211216113552.81199-2-andriy.shevchenko@linux.intel.comSigned-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Discourage people from using UAPI header in new code by adding a note.

Link: https://lkml.kernel.org/r/20211216113552.81199-1-andriy.shevchenko@linux.intel.comSigned-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When kernel.h is used in the headers it adds a lot into dependency hell,
especially when there are circular dependencies are involved.

Replace kernel.h inclusion with the list of what is really being used.

Link: https://lkml.kernel.org/r/20211213204441.56204-1-andriy.shevchenko@linux.intel.comSigned-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NBrendan Higgins <brendanhiggins@google.com>
Tested-by: NBrendan Higgins <brendanhiggins@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use KUnit framework to make tests more easily integrable with CIs.  Even
though these tests are not yet properly written as unit tests this
change should help in debugging.

Also remove kernel messages (i.e.  through pr_info) as KUnit handles all
debugging output and let it handle module init and exit details.

Link: https://lkml.kernel.org/r/20211208183711.390454-6-isabbasso@riseup.netReviewed-by: NDavid Gow <davidgow@google.com>
Reported-by: Nkernel test robot <lkp@intel.com>
Tested-by: NDavid Gow <davidgow@google.com>
Co-developed-by: NAugusto Durães Camargo <augusto.duraes33@gmail.com>
Signed-off-by: NAugusto Durães Camargo <augusto.duraes33@gmail.com>
Co-developed-by: NEnzo Ferreira <ferreiraenzoa@gmail.com>
Signed-off-by: NEnzo Ferreira <ferreiraenzoa@gmail.com>
Signed-off-by: NIsabella Basso <isabbasso@riseup.net>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Split TEST_HASH so that each entry only has one file.

Note that there's no stringhash test file, but actually
<linux/stringhash.h> tests are performed in lib/test_hash.c.

Link: https://lkml.kernel.org/r/20211208183711.390454-5-isabbasso@riseup.netReviewed-by: NDavid Gow <davidgow@google.com>
Tested-by: NDavid Gow <davidgow@google.com>
Signed-off-by: NIsabella Basso <isabbasso@riseup.net>
Cc: Augusto Durães Camargo <augusto.duraes33@gmail.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: Enzo Ferreira <ferreiraenzoa@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: kernel test robot <lkp@intel.com>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Split up test_hash_init so that it calls each test more explicitly
insofar it is possible without rewriting the entire file.  This aims at
improving readability.

Split tests performed on string_or as they don't interfere with those
performed in hash_or.  Also separate pr_info calls about skipped tests
as they're not part of the tests themselves, but only warn about
(un)defined arch-specific hash functions.

Link: https://lkml.kernel.org/r/20211208183711.390454-4-isabbasso@riseup.netReviewed-by: NDavid Gow <davidgow@google.com>
Tested-by: NDavid Gow <davidgow@google.com>
Signed-off-by: NIsabella Basso <isabbasso@riseup.net>
Cc: Augusto Durães Camargo <augusto.duraes33@gmail.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: Enzo Ferreira <ferreiraenzoa@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: kernel test robot <lkp@intel.com>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Split the test_int_hash function to keep its mainloop separate from
arch-specific chunks, which are only compiled as needed.  This aims at
improving readability.

Link: https://lkml.kernel.org/r/20211208183711.390454-3-isabbasso@riseup.netReviewed-by: NDavid Gow <davidgow@google.com>
Tested-by: NDavid Gow <davidgow@google.com>
Signed-off-by: NIsabella Basso <isabbasso@riseup.net>
Cc: Augusto Durães Camargo <augusto.duraes33@gmail.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: Enzo Ferreira <ferreiraenzoa@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: kernel test robot <lkp@intel.com>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "test_hash.c: refactor into KUnit", v3.

We refactored the lib/test_hash.c file into KUnit as part of the student
group LKCAMP [1] introductory hackathon for kernel development.

This test was pointed to our group by Daniel Latypov [2], so its full
conversion into a pure KUnit test was our goal in this patch series, but
we ran into many problems relating to it not being split as unit tests,
which complicated matters a bit, as the reasoning behind the original
tests is quite cryptic for those unfamiliar with hash implementations.

Some interesting developments we'd like to highlight are:

 - In patch 1/5 we noticed that there was an unused define directive
   that could be removed.

 - In patch 4/5 we noticed how stringhash and hash tests are all under
   the lib/test_hash.c file, which might cause some confusion, and we
   also broke those kernel config entries up.

Overall KUnit developments have been made in the other patches in this
series:

In patches 2/5, 3/5 and 5/5 we refactored the lib/test_hash.c file so as
to make it more compatible with the KUnit style, whilst preserving the
original idea of the maintainer who designed it (i.e.  George Spelvin),
which might be undesirable for unit tests, but we assume it is enough
for a first patch.

This patch (of 5):

Currently, there exist hash_32() and __hash_32() functions, which were
introduced in a patch [1] targeting architecture specific optimizations.
These functions can be overridden on a per-architecture basis to achieve
such optimizations.  They must set their corresponding define directive
(HAVE_ARCH_HASH_32 and HAVE_ARCH__HASH_32, respectively) so that header
files can deal with these overrides properly.

As the supported 32-bit architectures that have their own hash function
implementation (i.e.  m68k, Microblaze, H8/300, pa-risc) have only been
making use of the (more general) __hash_32() function (which only lacks
a right shift operation when compared to the hash_32() function), remove
the define directive corresponding to the arch-specific hash_32()
implementation.

[1] https://lore.kernel.org/lkml/20160525073311.5600.qmail@ns.sciencehorizons.net/

[akpm@linux-foundation.org: hash_32_generic() becomes hash_32()]

Link: https://lkml.kernel.org/r/20211208183711.390454-1-isabbasso@riseup.net
Link: https://lkml.kernel.org/r/20211208183711.390454-2-isabbasso@riseup.netReviewed-by: NDavid Gow <davidgow@google.com>
Tested-by: NDavid Gow <davidgow@google.com>
Co-developed-by: NAugusto Durães Camargo <augusto.duraes33@gmail.com>
Signed-off-by: NAugusto Durães Camargo <augusto.duraes33@gmail.com>
Co-developed-by: NEnzo Ferreira <ferreiraenzoa@gmail.com>
Signed-off-by: NEnzo Ferreira <ferreiraenzoa@gmail.com>
Signed-off-by: NIsabella Basso <isabbasso@riseup.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, the entry->prev and entry->next are considered to be valid as
long as they are not LIST_POISON{1|2}.  However, the memory may be
corrupted.  The prev->next is invalid probably because 'prev' is
invalid, not because prev->next's content is illegal.

Unfortunately, the printk and its subfunctions will modify the registers
that hold the 'prev' and 'next', and we don't see this valuable
information in the BUG context.

So print the contents of 'entry->prev' and 'entry->next'.

Here's an example:
  list_del corruption. prev->next should be c0ecbf74, but was c08410dc
  kernel BUG at lib/list_debug.c:53!
  ... ...
  PC is at __list_del_entry_valid+0x58/0x98
  LR is at __list_del_entry_valid+0x58/0x98
  psr: 60000093
  sp : c0ecbf30  ip : 00000000  fp : 00000001
  r10: c08410d0  r9 : 00000001  r8 : c0825e0c
  r7 : 20000013  r6 : c08410d0  r5 : c0ecbf74  r4 : c0ecbf74
  r3 : c0825d08  r2 : 00000000  r1 : df7ce6f4  r0 : 00000044
  ... ...
  Stack: (0xc0ecbf30 to 0xc0ecc000)
  bf20:                                     c0ecbf74 c0164fd0 c0ecbf70 c0165170
  bf40: c0eca000 c0840c00 c0840c00 c0824500 c0825e0c c0189bbc c088f404 60000013
  bf60: 60000013 c0e85100 000004ec 00000000 c0ebcdc0 c0ecbf74 c0ecbf74 c0825d08
  bf80: c0e807c0 c018965c 00000000 c013f2a0 c0e807c0 c013f154 00000000 00000000
  bfa0: 00000000 00000000 00000000 c01001b0 00000000 00000000 00000000 00000000
  bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
  bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 00000000
  (__list_del_entry_valid) from (__list_del_entry+0xc/0x20)
  (__list_del_entry) from (finish_swait+0x60/0x7c)
  (finish_swait) from (rcu_gp_kthread+0x560/0xa20)
  (rcu_gp_kthread) from (kthread+0x14c/0x15c)
  (kthread) from (ret_from_fork+0x14/0x24)

At first, I thought prev->next was overwritten.  Later, I carefully
analyzed the RCU code and the disassembly code.  The error occurred when
deleting a node from the list rcu_state.gp_wq.  The System.map shows
that the address of rcu_state is c0840c00.  Then I use gdb to obtain the
offset of rcu_state.gp_wq.task_list.

  (gdb) p &((struct rcu_state *)0)->gp_wq.task_list
  $1 = (struct list_head *) 0x4dc

Again:
  list_del corruption. prev->next should be c0ecbf74, but was c08410dc

  c08410dc = c0840c00 + 0x4dc = &rcu_state.gp_wq.task_list

Because rcu_state.gp_wq has at most one node, so I can guess that "prev
= &rcu_state.gp_wq.task_list".  But for other scenes, maybe I wasn't so
lucky, I cannot figure out the value of 'prev'.

Link: https://lkml.kernel.org/r/20211207025835.1909-1-thunder.leizhen@huawei.comSigned-off-by: NZhen Lei <thunder.leizhen@huawei.com>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce list_is_head() in the similar (*) way as it's done for
list_entry_is_head().  Make use of it in the list.h.

*) it's done as inliner and not a macro to be aligned with other
   list_is_*() APIs; while at it, make all three to have the same
   style.

Link: https://lkml.kernel.org/r/20211201141824.81400-1-andriy.shevchenko@linux.intel.comSigned-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I've made a mistake of looking into lib/kstrtox.o code generation.

The only function remotely performance critical is _parse_integer()
(via /proc/*/map_files/*), everything else is not.

Uninline everything, shrink lib/kstrtox.o by ~20 % !

Space savings on x86_64:

	add/remove: 0/0 grow/shrink: 0/23 up/down: 0/-1269 (-1269 !!!)
	Function                                     old     new   delta
	kstrtoull                                     16      13      -3
	kstrtouint                                    59      48     -11
	kstrtou8                                      60      49     -11
	kstrtou16                                     61      50     -11
	_kstrtoul                                     46      35     -11
	kstrtoull_from_user                           95      83     -12
	kstrtoul_from_user                            95      83     -12
	kstrtoll                                      93      80     -13
	kstrtouint_from_user                         124      83     -41
	kstrtou8_from_user                           125      83     -42
	kstrtou16_from_user                          126      83     -43
	kstrtos8                                     101      50     -51
	kstrtos16                                    102      51     -51
	kstrtoint                                    100      49     -51
	_kstrtol                                      93      35     -58
	kstrtobool_from_user                         156      75     -81
	kstrtoll_from_user                           165      83     -82
	kstrtol_from_user                            165      83     -82
	kstrtoint_from_user                          172      83     -89
	kstrtos8_from_user                           173      83     -90
	kstrtos16_from_user                          174      83     -91
	_parse_integer                               136      10    -126
	_kstrtoull                                   308     101    -207
	Total: Before=3421236, After=3419967, chg -0.04%

Link: https://lkml.kernel.org/r/YZDsFDhHst4m2Pnt@localhost.localdomainSigned-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When --nogit is used with scripts/get_maintainer.pl, the script spews 4
lines of unnecessary information (noise).  Do not print those lines when
--nogit is specified.

This change removes the printing of these 4 lines:

  ./scripts/get_maintainer.pl: No supported VCS found.  Add --nogit to options?
  Using a git repository produces better results.
  Try Linus Torvalds' latest git repository using:
  git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

Link: https://lkml.kernel.org/r/20220102031424.3328-1-rdunlap@infradead.orgSigned-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

PRIO_PGRP needs the tasklist_lock mainly to serialize vs setpgid(2), to
protect against any concurrent change_pid(PIDTYPE_PGID) that can move
the task from one hlist to another while iterating.

However, the remaining can only rely only on RCU:

PRIO_PROCESS only does the task lookup and never iterates over tasklist
and we already have an rcu-aware stable pointer.

PRIO_USER is already racy vs setuid(2) so with creds being rcu
protected, we can end up seeing stale data.  When removing the
tasklist_lock there can be a race with (i) fork but this is benign as
the child's nice is inherited and the new task is not observable by the
user yet either, hence the return semantics do not differ.  And (ii) a
race with exit, which is a small window and can cause us to miss a task
which was removed from the list and it had the highest nice.

Similarly change the buggy do_each_thread/while_each_thread combo in
PRIO_USER for the rcu-safe for_each_process_thread flavor, which doesn't
make use of next_thread/p->thread_group.

[akpm@linux-foundation.org: coding style fixes]

Link: https://lkml.kernel.org/r/20211210182250.43734-1-dave@stgolabs.netSigned-off-by: NDavidlohr Bueso <dbueso@suse.de>
Acked-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When I was implementing a new per-cpu kthread cfs_migration, I found the
comm of it "cfs_migration/%u" is truncated due to the limitation of
TASK_COMM_LEN.  For example, the comm of the percpu thread on CPU10~19
all have the same name "cfs_migration/1", which will confuse the user.
This issue is not critical, because we can get the corresponding CPU
from the task's Cpus_allowed.  But for kthreads corresponding to other
hardware devices, it is not easy to get the detailed device info from
task comm, for example,

    jbd2/nvme0n1p2-
    xfs-reclaim/sdf

Currently there are so many truncated kthreads:

    rcu_tasks_kthre
    rcu_tasks_rude_
    rcu_tasks_trace
    poll_mpt3sas0_s
    ext4-rsv-conver
    xfs-reclaim/sd{a, b, c, ...}
    xfs-blockgc/sd{a, b, c, ...}
    xfs-inodegc/sd{a, b, c, ...}
    audit_send_repl
    ecryptfs-kthrea
    vfio-irqfd-clea
    jbd2/nvme0n1p2-
    ...

We can shorten these names to work around this problem, but it may be
not applied to all of the truncated kthreads.  Take 'jbd2/nvme0n1p2-'
for example, it is a nice name, and it is not a good idea to shorten it.

One possible way to fix this issue is extending the task comm size, but
as task->comm is used in lots of places, that may cause some potential
buffer overflows.  Another more conservative approach is introducing a
new pointer to store kthread's full name if it is truncated, which won't
introduce too much overhead as it is in the non-critical path.  Finally
we make a dicision to use the second approach.  See also the discussions
in this thread:
https://lore.kernel.org/lkml/20211101060419.4682-1-laoar.shao@gmail.com/

After this change, the full name of these truncated kthreads will be
displayed via /proc/[pid]/comm:

    rcu_tasks_kthread
    rcu_tasks_rude_kthread
    rcu_tasks_trace_kthread
    poll_mpt3sas0_statu
    ext4-rsv-conversion
    xfs-reclaim/sdf1
    xfs-blockgc/sdf1
    xfs-inodegc/sdf1
    audit_send_reply
    ecryptfs-kthread
    vfio-irqfd-cleanup
    jbd2/nvme0n1p2-8

Link: https://lkml.kernel.org/r/20211120112850.46047-1-laoar.shao@gmail.comSigned-off-by: NYafang Shao <laoar.shao@gmail.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NPetr Mladek <pmladek@suse.com>
Suggested-by: NPetr Mladek <pmladek@suse.com>
Suggested-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As the sched:sched_switch tracepoint args are derived from the kernel,
we'd better make it same with the kernel.  So the macro TASK_COMM_LEN is
converted to type enum, then all the BPF programs can get it through
BTF.

The BPF program which wants to use TASK_COMM_LEN should include the
header vmlinux.h.  Regarding the test_stacktrace_map and
test_tracepoint, as the type defined in linux/bpf.h are also defined in
vmlinux.h, so we don't need to include linux/bpf.h again.

Link: https://lkml.kernel.org/r/20211120112738.45980-8-laoar.shao@gmail.comSigned-off-by: NYafang Shao <laoar.shao@gmail.com>
Acked-by: NAndrii Nakryiko <andrii@kernel.org>
Acked-by: NDavid Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

tools/bpf/bpftool/skeleton: replace bpf_probe_read_kernel with bpf_probe_read_kernel_str to get task comm

bpf_probe_read_kernel_str() will add a nul terminator to the dst, then
we don't care about if the dst size is big enough.

Link: https://lkml.kernel.org/r/20211120112738.45980-7-laoar.shao@gmail.comSigned-off-by: NYafang Shao <laoar.shao@gmail.com>
Acked-by: NAndrii Nakryiko <andrii@kernel.org>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

samples/bpf/test_overhead_kprobe_kern: replace bpf_probe_read_kernel with bpf_probe_read_kernel_str to get task comm

bpf_probe_read_kernel_str() will add a nul terminator to the dst, then
we don't care about if the dst size is big enough.  This patch also
replaces the hard-coded 16 with TASK_COMM_LEN to make it grepable.

Link: https://lkml.kernel.org/r/20211120112738.45980-6-laoar.shao@gmail.comSigned-off-by: NYafang Shao <laoar.shao@gmail.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Acked-by: NAndrii Nakryiko <andrii@kernel.org>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It is better to use get_task_comm() instead of the open coded string
copy as we do in other places.

struct elf_prpsinfo is used to dump the task information in userspace
coredump or kernel vmcore.  Below is the verification of vmcore,

  crash> ps
     PID    PPID  CPU       TASK        ST  %MEM     VSZ    RSS  COMM
        0      0   0  ffffffff9d21a940  RU   0.0       0      0  [swapper/0]
  >     0      0   1  ffffa09e40f85e80  RU   0.0       0      0  [swapper/1]
  >     0      0   2  ffffa09e40f81f80  RU   0.0       0      0  [swapper/2]
  >     0      0   3  ffffa09e40f83f00  RU   0.0       0      0  [swapper/3]
  >     0      0   4  ffffa09e40f80000  RU   0.0       0      0  [swapper/4]
  >     0      0   5  ffffa09e40f89f80  RU   0.0       0      0  [swapper/5]
        0      0   6  ffffa09e40f8bf00  RU   0.0       0      0  [swapper/6]
  >     0      0   7  ffffa09e40f88000  RU   0.0       0      0  [swapper/7]
  >     0      0   8  ffffa09e40f8de80  RU   0.0       0      0  [swapper/8]
  >     0      0   9  ffffa09e40f95e80  RU   0.0       0      0  [swapper/9]
  >     0      0  10  ffffa09e40f91f80  RU   0.0       0      0  [swapper/10]
  >     0      0  11  ffffa09e40f93f00  RU   0.0       0      0  [swapper/11]
  >     0      0  12  ffffa09e40f90000  RU   0.0       0      0  [swapper/12]
  >     0      0  13  ffffa09e40f9bf00  RU   0.0       0      0  [swapper/13]
  >     0      0  14  ffffa09e40f98000  RU   0.0       0      0  [swapper/14]
  >     0      0  15  ffffa09e40f9de80  RU   0.0       0      0  [swapper/15]

It works well as expected.

Some comments are added to explain why we use the hard-coded 16.

Link: https://lkml.kernel.org/r/20211120112738.45980-5-laoar.shao@gmail.comSuggested-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NYafang Shao <laoar.shao@gmail.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We'd better use the helper get_task_comm() rather than the open-coded
strlcpy() to get task comm.  As the comment above the hard-coded 16, we
can replace it with TASK_COMM_LEN.

Link: https://lkml.kernel.org/r/20211120112738.45980-4-laoar.shao@gmail.comSigned-off-by: NYafang Shao <laoar.shao@gmail.com>
Acked-by: NDennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the dest buffer size is smaller than sizeof(tsk->comm), the buffer
will be without null ternimator, that may cause problem.  Using
strscpy_pad() instead of strncpy() in __get_task_comm() can make the
string always nul ternimated and zero padded.

Link: https://lkml.kernel.org/r/20211120112738.45980-3-laoar.shao@gmail.comSuggested-by: NKees Cook <keescook@chromium.org>
Suggested-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NYafang Shao <laoar.shao@gmail.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "task comm cleanups", v2.

This patchset is part of the patchset "extend task comm from 16 to
24"[1].  Now we have different opinion that dynamically allocates memory
to store kthread's long name into a separate pointer, so I decide to
take the useful cleanups apart from the original patchset and send it
separately[2].

These useful cleanups can make the usage around task comm less
error-prone.  Furthermore, it will be useful if we want to extend task
comm in the future.

[1]. https://lore.kernel.org/lkml/20211101060419.4682-1-laoar.shao@gmail.com/
[2]. https://lore.kernel.org/lkml/CALOAHbAx55AUo3bm8ZepZSZnw7A08cvKPdPyNTf=E_tPqmw5hw@mail.gmail.com/

This patch (of 7):

strlcpy() can trigger out-of-bound reads on the source string[1], we'd
better use strscpy() instead.  To make it be robust against full tsk->comm
copies that got noticed in other places, we should make sure it's zero
padded.

[1] https://github.com/KSPP/linux/issues/89

Link: https://lkml.kernel.org/r/20211120112738.45980-1-laoar.shao@gmail.com
Link: https://lkml.kernel.org/r/20211120112738.45980-2-laoar.shao@gmail.comSigned-off-by: NYafang Shao <laoar.shao@gmail.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Include a note at the top to discourage people from including it in
headers.

Link: https://lkml.kernel.org/r/20211209150803.4473-1-andriy.shevchenko@linux.intel.comSigned-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When kernel.h is used in the headers it adds a lot into dependency hell,
especially when there are circular dependencies are involved.

Replace kernel.h inclusion with the list of what is really being used.

The rest of the changes are induced by the above and may not be split.

Link: https://lkml.kernel.org/r/20211209123823.20425-1-andriy.shevchenko@linux.intel.comSigned-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Arend van Spriel <arend.vanspriel@broadcom.com>	[brcmfmac]
Acked-by: NKalle Valo <kvalo@kernel.org>
Cc: Arend van Spriel <aspriel@gmail.com>
Cc: Franky Lin <franky.lin@broadcom.com>
Cc: Hante Meuleman <hante.meuleman@broadcom.com>
Cc: Chi-hsien Lin <chi-hsien.lin@infineon.com>
Cc: Wright Feng <wright.feng@infineon.com>
Cc: Chung-hsien Hsu <chung-hsien.hsu@infineon.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Subsequent if judgments will assign new values to ret, so the statement
here should be deleted

The clang_analyzer complains as follows:

  fs/proc/proc_sysctl.c:
  Value stored to 'ret' is never read

Link: https://lkml.kernel.org/r/20211230063622.586360-1-luo.penghao@zte.com.cnSigned-off-by: Nluo penghao <luo.penghao@zte.com.cn>
Reported-by: NZeal Robot <zealci@zte.com.cn>
Acked-by: NLuis Chamberlain <mcgrof@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

sysctl_print_dir() always terminates the printed path name with a slash,
so printing a slash before the file part causes a duplicate like in

    sysctl duplicate entry: /kernel//perf_user_access

Fix this by dropping the extra slash.

Link: https://lkml.kernel.org/r/e3054d605dc56f83971e4b6d2f5fa63a978720ad.1641551872.git.geert+renesas@glider.beSigned-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NChristian Brauner <christian.brauner@ubuntu.com>
Acked-by: NLuis Chamberlain <mcgrof@kernel.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert return type of proc_fd_access_allowed() and the 'allowed' in it
to be boolean since the return type of ptrace_may_access() is boolean.

Link: https://lkml.kernel.org/r/20211219024404.29779-1-zhengqi.arch@bytedance.comSigned-off-by: NQi Zheng <zhengqi.arch@bytedance.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change the proc_create[_data]() stubs which are used when CONFIG_PROC_FS
is not set from #defines to a static inline stubs.

This should fix clang -Werror builds failing due to errors like this:

  drivers/platform/x86/thinkpad_acpi.c:918:30: error: unused variable
   'dispatch_proc_ops' [-Werror,-Wunused-const-variable]

Fixing this in include/linux/proc_fs.h should ensure that the same issue
is also fixed in any other drivers hitting the same -Werror issue.

[akpm@linux-foundation.org: fix CONFIG_PROC_FS=n]
[akpm@linux-foundation.org: fix arch/sparc/kernel/led.c]
[akpm@linux-foundation.org: fix build]

Link: https://lkml.kernel.org/r/20211116131112.508304-1-hdegoede@redhat.comSigned-off-by: NHans de Goede <hdegoede@redhat.com>
Reported-by: Nkernel test robot <lkp@intel.com>
Acked-by: NChristian Brauner <christian.brauner@ubuntu.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In commit cc5f2704 ("proc/vmcore: convert oldmem_pfn_is_ram callback
to more generic vmcore callbacks"), we added detection of surprise
vmcore_cb unregistration after the vmcore was already opened.  Once
detected, we warn the user and simulate reading zeroes from that point
on when accessing the vmcore.

The basic reason was that unexpected unregistration, for example, by
manually unbinding a driver from a device after opening the vmcore, is
not supported and could result in reading oldmem the vmcore_cb would
have actually prohibited while registered.  However, something like that
can similarly be trigger by a user that's really looking for trouble
simply by unbinding the relevant driver before opening the vmcore -- or
by disallowing loading the driver in the first place.  So it's actually
of limited help.

Currently, unregistration can only be triggered via virtio-mem when
manually unbinding the driver from the device inside the VM; there is no
way to trigger it from the hypervisor, as hypervisors don't allow for
unplugging virtio-mem devices -- ripping out system RAM from a VM
without coordination with the guest is usually not a good idea.

The important part is that unbinding the driver and unregistering the
vmcore_cb while concurrently reading the vmcore won't crash the system,
and that is handled by the rwsem.

To make the mechanism more future proof, let's remove the "read zero"
part, but leave the warning in place.  For example, we could have a
future driver (like virtio-balloon) that will contact the hypervisor to
figure out if we already populated a page for a given PFN.
Hotunplugging such a device and consequently unregistering the vmcore_cb
could be triggered from the hypervisor without harming the system even
while kdump is running.  In that case, we don't want to silently end up
with a vmcore that contains wrong data, because the user inside the VM
might be unaware of the hypervisor action and might easily miss the
warning in the log.

Link: https://lkml.kernel.org/r/20211111192243.22002-1-david@redhat.comSigned-off-by: NDavid Hildenbrand <david@redhat.com>
Acked-by: NBaoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Philipp Rudo <prudo@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With NEED_PER_CPU_PAGE_FIRST_CHUNK enabled, we need a function to
populate pte, this patch adds a generic pcpu populate pte function,
pcpu_populate_pte(), which is marked __weak and used on most
architectures, but it is overridden on x86, which has its own
implementation.

Link: https://lkml.kernel.org/r/20211216112359.103822-5-wangkefeng.wang@huawei.comSigned-off-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With the previous patch, we could add a generic pcpu first chunk
allocate and free function to cleanup the duplicated definations on each
architecture.

Link: https://lkml.kernel.org/r/20211216112359.103822-4-wangkefeng.wang@huawei.comSigned-off-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add pcpu_fc_cpu_to_node_fn_t and pass it into pcpu_fc_alloc_fn_t, pcpu
first chunk allocation will call it to alloc memblock on the
corresponding node by it, this is prepare for the next patch.

Link: https://lkml.kernel.org/r/20211216112359.103822-3-wangkefeng.wang@huawei.comSigned-off-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "mm: percpu: Cleanup percpu first chunk function".

When supporting page mapping percpu first chunk allocator on arm64, we
found there are lots of duplicated codes in percpu embed/page first chunk
allocator.  This patchset is aimed to cleanup them and should no function
change.

The currently supported status about 'embed' and 'page' in Archs shows
below,

	embed: NEED_PER_CPU_PAGE_FIRST_CHUNK
	page:  NEED_PER_CPU_EMBED_FIRST_CHUNK

		embed	page
	------------------------
	arm64	  Y	 Y
	mips	  Y	 N
	powerpc	  Y	 Y
	riscv	  Y	 N
	sparc	  Y	 Y
	x86	  Y	 Y
	------------------------

There are two interfaces about percpu first chunk allocator,

 extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
                                size_t atom_size,
                                pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
-                               pcpu_fc_alloc_fn_t alloc_fn,
-                               pcpu_fc_free_fn_t free_fn);
+                               pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);

 extern int __init pcpu_page_first_chunk(size_t reserved_size,
-                               pcpu_fc_alloc_fn_t alloc_fn,
-                               pcpu_fc_free_fn_t free_fn,
-                               pcpu_fc_populate_pte_fn_t populate_pte_fn);
+                               pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);

The pcpu_fc_alloc_fn_t/pcpu_fc_free_fn_t is killed, we provide generic
pcpu_fc_alloc() and pcpu_fc_free() function, which are called in the
pcpu_embed/page_first_chunk().

1) For pcpu_embed_first_chunk(), pcpu_fc_cpu_to_node_fn_t is needed to be
   provided when archs supported NUMA.

2) For pcpu_page_first_chunk(), the pcpu_fc_populate_pte_fn_t is killed too,
   a generic pcpu_populate_pte() which marked '__weak' is provided, if you
   need a different function to populate pte on the arch(like x86), please
   provide its own implementation.

[1] https://github.com/kevin78/linux.git percpu-cleanup

This patch (of 4):

The HAVE_SETUP_PER_CPU_AREA/NEED_PER_CPU_EMBED_FIRST_CHUNK/
NEED_PER_CPU_PAGE_FIRST_CHUNK/USE_PERCPU_NUMA_NODE_ID configs, which have
duplicate definitions on platforms that subscribe it.

Move them into mm, drop these redundant definitions and instead just
select it on applicable platforms.

Link: https://lkml.kernel.org/r/20211216112359.103822-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20211216112359.103822-2-wangkefeng.wang@huawei.comSigned-off-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Cc: Will Deacon <will@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>