This changes {,__}kasan_check_{read,write} functions to return a boolean
denoting if the access was valid or not.

[sfr@canb.auug.org.au: include types.h for "bool"]
  Link: http://lkml.kernel.org/r/20190705184949.13cdd021@canb.auug.org.au
Link: http://lkml.kernel.org/r/20190626142014.141844-3-elver@google.comSigned-off-by: NMarco Elver <elver@google.com>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "mm/kasan: Add object validation in ksize()", v3.

This patch (of 5):

This introduces __kasan_check_{read,write}.  __kasan_check functions may
be used from anywhere, even compilation units that disable instrumentation
selectively.

This change eliminates the need for the __KASAN_INTERNAL definition.

[elver@google.com: v5]
  Link: http://lkml.kernel.org/r/20190708170706.174189-2-elver@google.com
Link: http://lkml.kernel.org/r/20190626142014.141844-2-elver@google.comSigned-off-by: NMarco Elver <elver@google.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Reviewed-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds a new header to asm-generic to allow optionally instrumenting
architecture-specific asm implementations of bitops.

This change includes the required change for x86 as reference and
changes the kernel API doc to point to bitops-instrumented.h instead.
Rationale: the functions in x86's bitops.h are no longer the kernel API
functions, but instead the arch_ prefixed functions, which are then
instrumented via bitops-instrumented.h.

Other architectures can similarly add support for asm implementations of
bitops.

The documentation text was derived from x86 and existing bitops
asm-generic versions: 1) references to x86 have been removed; 2) as a
result, some of the text had to be reworded for clarity and consistency.

Tested using lib/test_kasan with bitops tests (pre-requisite patch).
Bugzilla ref: https://bugzilla.kernel.org/show_bug.cgi?id=198439

Link: http://lkml.kernel.org/r/20190613125950.197667-4-elver@google.comSigned-off-by: NMarco Elver <elver@google.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Reviewed-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch is a pre-requisite for enabling KASAN bitops instrumentation;
using static_cpu_has instead of boot_cpu_has avoids instrumentation of
test_bit inside the uaccess region.  With instrumentation, the KASAN
check would otherwise be flagged by objtool.

For consistency, kernel/signal.c was changed to mirror this change,
however, is never instrumented with KASAN (currently unsupported under
x86 32bit).

Link: http://lkml.kernel.org/r/20190613125950.197667-3-elver@google.comSigned-off-by: NMarco Elver <elver@google.com>
Suggested-by: NH. Peter Anvin <hpa@zytor.com>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "Bitops instrumentation for KASAN", v5.

This patch (of 3):

This adds bitops tests to the test_kasan module.  In a follow-up patch,
support for bitops instrumentation will be added.

Link: http://lkml.kernel.org/r/20190613125950.197667-2-elver@google.comSigned-off-by: NMarco Elver <elver@google.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Reviewed-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds support for printing stack frame description on invalid stack
accesses.  The frame description is embedded by the compiler, which is
parsed and then pretty-printed.

Currently, we can only print the stack frame info for accesses to the
task's own stack, but not accesses to other tasks' stacks.

Example of what it looks like:

  page dumped because: kasan: bad access detected

  addr ffff8880673ef98a is located in stack of task insmod/2008 at offset 106 in frame:
   kasan_stack_oob+0x0/0xf5 [test_kasan]

  this frame has 2 objects:
   [32, 36) 'i'
   [96, 106) 'stack_array'

  Memory state around the buggy address:

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=198435
Link: http://lkml.kernel.org/r/20190522100048.146841-1-elver@google.comSigned-off-by: NMarco Elver <elver@google.com>
Reviewed-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Wikipedia now has a main article to "tracing garbage collector" topic.
Change the URL and use the reStructuredText syntax for hyperlinks and add
more details about the use of the tool.  Add a section about how to use
the kmemleak-test module to test the memory leak scanning.

Link: http://lkml.kernel.org/r/20190612155231.19448-2-andrealmeid@collabora.comSigned-off-by: NAndré Almeida <andrealmeid@collabora.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

According to POSIX, EBUSY means that the "device or resource is busy", and
this can lead to people thinking that the file
`/sys/kernel/debug/kmemleak/` is somehow locked or being used by other
process.  Change this error code to a more appropriate one.

Link: http://lkml.kernel.org/r/20190612155231.19448-1-andrealmeid@collabora.comSigned-off-by: NAndré Almeida <andrealmeid@collabora.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

in_softirq() is a wrong predicate to check if we are in a softirq
context.  It also returns true if we have BH disabled, so objects are
falsely stamped with "softirq" comm.  The correct predicate is
in_serving_softirq().

If user does cat from /sys/kernel/debug/kmemleak previously they would
see this, which is clearly wrong, this is system call context (see the
comm):

unreferenced object 0xffff88805bd661c0 (size 64):
  comm "softirq", pid 0, jiffies 4294942959 (age 12.400s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 ff ff ff ff 00 00 00 00  ................
    00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
  backtrace:
    [<0000000007dcb30c>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
    [<0000000007dcb30c>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<0000000007dcb30c>] slab_alloc mm/slab.c:3326 [inline]
    [<0000000007dcb30c>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
    [<00000000969722b7>] kmalloc include/linux/slab.h:547 [inline]
    [<00000000969722b7>] kzalloc include/linux/slab.h:742 [inline]
    [<00000000969722b7>] ip_mc_add1_src net/ipv4/igmp.c:1961 [inline]
    [<00000000969722b7>] ip_mc_add_src+0x36b/0x400 net/ipv4/igmp.c:2085
    [<00000000a4134b5f>] ip_mc_msfilter+0x22d/0x310 net/ipv4/igmp.c:2475
    [<00000000d20248ad>] do_ip_setsockopt.isra.0+0x19fe/0x1c00 net/ipv4/ip_sockglue.c:957
    [<000000003d367be7>] ip_setsockopt+0x3b/0xb0 net/ipv4/ip_sockglue.c:1246
    [<000000003c7c76af>] udp_setsockopt+0x4e/0x90 net/ipv4/udp.c:2616
    [<000000000c1aeb23>] sock_common_setsockopt+0x3e/0x50 net/core/sock.c:3130
    [<000000000157b92b>] __sys_setsockopt+0x9e/0x120 net/socket.c:2078
    [<00000000a9f3d058>] __do_sys_setsockopt net/socket.c:2089 [inline]
    [<00000000a9f3d058>] __se_sys_setsockopt net/socket.c:2086 [inline]
    [<00000000a9f3d058>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086
    [<000000001b8da885>] do_syscall_64+0x7c/0x1a0 arch/x86/entry/common.c:301
    [<00000000ba770c62>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

now they will see this:

unreferenced object 0xffff88805413c800 (size 64):
  comm "syz-executor.4", pid 8960, jiffies 4294994003 (age 14.350s)
  hex dump (first 32 bytes):
    00 7a 8a 57 80 88 ff ff e0 00 00 01 00 00 00 00  .z.W............
    00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000c5d3be64>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
    [<00000000c5d3be64>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<00000000c5d3be64>] slab_alloc mm/slab.c:3326 [inline]
    [<00000000c5d3be64>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
    [<0000000023865be2>] kmalloc include/linux/slab.h:547 [inline]
    [<0000000023865be2>] kzalloc include/linux/slab.h:742 [inline]
    [<0000000023865be2>] ip_mc_add1_src net/ipv4/igmp.c:1961 [inline]
    [<0000000023865be2>] ip_mc_add_src+0x36b/0x400 net/ipv4/igmp.c:2085
    [<000000003029a9d4>] ip_mc_msfilter+0x22d/0x310 net/ipv4/igmp.c:2475
    [<00000000ccd0a87c>] do_ip_setsockopt.isra.0+0x19fe/0x1c00 net/ipv4/ip_sockglue.c:957
    [<00000000a85a3785>] ip_setsockopt+0x3b/0xb0 net/ipv4/ip_sockglue.c:1246
    [<00000000ec13c18d>] udp_setsockopt+0x4e/0x90 net/ipv4/udp.c:2616
    [<0000000052d748e3>] sock_common_setsockopt+0x3e/0x50 net/core/sock.c:3130
    [<00000000512f1014>] __sys_setsockopt+0x9e/0x120 net/socket.c:2078
    [<00000000181758bc>] __do_sys_setsockopt net/socket.c:2089 [inline]
    [<00000000181758bc>] __se_sys_setsockopt net/socket.c:2086 [inline]
    [<00000000181758bc>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086
    [<00000000d4b73623>] do_syscall_64+0x7c/0x1a0 arch/x86/entry/common.c:301
    [<00000000c1098bec>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Link: http://lkml.kernel.org/r/20190517171507.96046-1-dvyukov@gmail.comSigned-off-by: NDmitry Vyukov <dvyukov@google.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently for CONFIG_SLUB, if a memcg kmem cache creation is failed and
the corresponding root kmem cache has SLAB_PANIC flag, the kernel will
be crashed.  This is unnecessary as the kernel can handle the creation
failures of memcg kmem caches.  Additionally CONFIG_SLAB does not
implement this behavior.  So, to keep the behavior consistent between
SLAB and SLUB, removing the panic for memcg kmem cache creation
failures.  The root kmem cache creation failure for SLAB_PANIC correctly
panics for both SLAB and SLUB.

Link: http://lkml.kernel.org/r/20190619232514.58994-1-shakeelb@google.comReported-by: NDave Hansen <dave.hansen@intel.com>
Signed-off-by: NShakeel Butt <shakeelb@google.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If ',' is not found, kmem_cache_flags() calls strlen() to find the end of
line.  We can do it in a single pass using strchrnul().

Link: http://lkml.kernel.org/r/20190501053111.7950-1-ynorov@marvell.comSigned-off-by: NYury Norov <ynorov@marvell.com>
Acked-by: NAaron Tomlin <atomlin@redhat.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds tests for double free and cross-cache freeing, which should both
be caught by CONFIG_SLAB_FREELIST_HARDENED.

Link: http://lkml.kernel.org/r/20190530045017.15252-4-keescook@chromium.orgSigned-off-by: NKees Cook <keescook@chromium.org>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This avoids any possible type confusion when looking up an object.  For
example, if a non-slab were to be passed to kfree(), the invalid
slab_cache pointer (i.e.  overlapped with some other value from the
struct page union) would be used for subsequent slab manipulations that
could lead to further memory corruption.

Since the page is already in cache, adding the PageSlab() check will
have nearly zero cost, so add a check and WARN() to virt_to_cache().
Additionally replaces an open-coded virt_to_cache().  To support the
failure mode this also updates all callers of virt_to_cache() and
cache_from_obj() to handle a NULL cache pointer return value (though
note that several already handle this case gracefully).

[dan.carpenter@oracle.com: restore IRQs in kfree()]
  Link: http://lkml.kernel.org/r/20190613065637.GE16334@mwanda
Link: http://lkml.kernel.org/r/20190530045017.15252-3-keescook@chromium.orgSigned-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "mm/slab: Improved sanity checking".

This adds defenses against slab cache confusion (as seen in real-world
exploits[1]) and gracefully handles type confusions when trying to look
up slab caches from an arbitrary page.  (Also is patch 3: new LKDTM
tests for these defenses as well as for the existing double-free
detection.

This patch (of 3):

When building under CONFIG_SLAB_FREELIST_HARDENING, it makes sense to
perform sanity-checking on the assumed slab cache during
kmem_cache_free() to make sure the kernel doesn't mix freelists across
slab caches and corrupt memory (as seen in the exploitation of flaws
like CVE-2018-9568[1]).  Note that the prior code might WARN() but still
corrupt memory (i.e.  return the assumed cache instead of the owned
cache).

There is no noticeable performance impact (changes are within noise).
Measuring parallel kernel builds, I saw the following with
CONFIG_SLAB_FREELIST_HARDENED, before and after this patch:

before:

	Run times: 288.85 286.53 287.09 287.07 287.21
	Min: 286.53 Max: 288.85 Mean: 287.35 Std Dev: 0.79

after:

	Run times: 289.58 287.40 286.97 287.20 287.01
	Min: 286.97 Max: 289.58 Mean: 287.63 Std Dev: 0.99

Delta: 0.1% which is well below the standard deviation

[1] https://github.com/ThomasKing2014/slides/raw/master/Building%20universal%20Android%20rooting%20with%20a%20type%20confusion%20vulnerability.pdf

Link: http://lkml.kernel.org/r/20190530045017.15252-2-keescook@chromium.orgSigned-off-by: NKees Cook <keescook@chromium.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kmemdup is introduced to duplicate a region of memory in a neat way.

Rather than kmalloc/kzalloc + memcpy, which the programmer needs to
write the size twice (sometimes lead to mistakes), kmemdup improves
readability, leads to smaller code and also reduce the chances of
mistakes.

Suggestion to use kmemdup rather than using kmalloc/kzalloc + memcpy.

[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/20190703163147.881-1-huangfq.daxian@gmail.comSigned-off-by: NFuqian Huang <huangfq.daxian@gmail.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fix below issue reported by coccicheck

  fs/ocfs2/dlmglue.c:4410:5-11: Unneeded variable: "status". Return "0" on line 4428

We can not change return type of ocfs2_downconvert_thread as its
registered as callback of kthread_create.

Link: http://lkml.kernel.org/r/20190702183237.GA13975@hari-Inspiron-1545Signed-off-by: NHariprasad Kelam <hariprasad.kelam@gmail.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Also, because there is no need to save the file dentry, remove all of
the variables that were being saved, and just recursively delete the
whole directory when shutting down, saving a lot of logic and local
variables.

[gregkh@linuxfoundation.org: v2]
  Link: http://lkml.kernel.org/r/20190613055455.GE19717@kroah.com
Link: http://lkml.kernel.org/r/20190612152912.GA19151@kroah.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Jia Guo <guojia12@huawei.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ocfs2 file system uses locking_state file under debugfs to dump each
ocfs2 file system's dlm lock resources, but the users ever encountered
some hang(deadlock) problems in ocfs2 file system.  I'd like to add
first lock wait time in locking_state file, which can help the upper
scripts detect these deadlock problems via comparing the first lock wait
time with the current time.

Link: http://lkml.kernel.org/r/20190611015414.27754-3-ghe@suse.comSigned-off-by: NGang He <ghe@suse.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add locking filter debugfs file, which is used to filter lock resources
dump from locking_state debugfs file.  We use d_filter_secs field to
filter lock resources dump, the default d_filter_secs(0) value filters
nothing, otherwise, only dump the last N seconds active lock resources.
This enhancement can avoid dumping lots of old records.  The
d_filter_secs value can be changed via locking_filter file.

[akpm@linux-foundation.org: fix undefined reference to `__udivdi3']
Link: http://lkml.kernel.org/r/20190611015414.27754-2-ghe@suse.comSigned-off-by: NGang He <ghe@suse.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>	[build-tested]
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ocfs2 file system uses locking_state file under debugfs to dump each
ocfs2 file system's dlm lock resources, but the dlm lock resources in
memory are becoming more and more after the files were touched by the
user.  it will become a bit difficult to analyze these dlm lock resource
records in locking_state file by the upper scripts, though some files
are not active for now, which were accessed long time ago.

Then, I'd like to add last pr/ex unlock times in locking_state file for
each dlm lock resource record, the the upper scripts can use last unlock
time to filter inactive dlm lock resource record.

Link: http://lkml.kernel.org/r/20190611015414.27754-1-ghe@suse.comSigned-off-by: NGang He <ghe@suse.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array.  For example:

  struct dlm_migratable_lockres
  {
          ...
          struct dlm_migratable_lock ml[0];  // 16 bytes each, begins at byte 112
  };

Make use of the struct_size() helper instead of an open-coded version in
order to avoid any potential type mistakes.

So, replace the following form:

   sizeof(struct dlm_migratable_lockres) + (mres->num_locks * sizeof(struct dlm_migratable_lock))

with:

   struct_size(mres, ml, mres->num_locks)

Notice that, in this case, variable sz is not necessary, hence it is
removed.

This code was detected with the help of Coccinelle.

Link: http://lkml.kernel.org/r/20190605204926.GA24467@embeddedorSigned-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are some spelling mistakes in ocfs, fix it.

Link: http://lkml.kernel.org/r/1558964623-106628-1-git-send-email-cg.chen@huawei.comSigned-off-by: NChenGang <cg.chen@huawei.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When building drm/exynos for sh, as part of an allmodconfig build, the
following warning triggered:

  exynos7_drm_decon.c: In function `decon_remove':
  exynos7_drm_decon.c:769:24: warning: unused variable `ctx'
    struct decon_context *ctx = dev_get_drvdata(&pdev->dev);

The ctx variable is only used as argument to iounmap().

In sh - allmodconfig CONFIG_MMU is not defined
so it ended up in:

\#define __iounmap(addr)	do { } while (0)
\#define iounmap		__iounmap

Fix the warning by introducing a static inline function for iounmap.

This is similar to several other architectures.

Link: http://lkml.kernel.org/r/20190622114208.24427-1-sam@ravnborg.orgSigned-off-by: NSam Ravnborg <sam@ravnborg.org>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

CONFIG_BACKLIGHT_LCD_SUPPORT was removed in 8c5dc8d9 ("video:
backlight: Remove useless BACKLIGHT_LCD_SUPPORT kernel symbol").
Options protected by CONFIG_BACKLIGHT_LCD_SUPPORT are now available
directly.

Link: http://lkml.kernel.org/r/20190603191925.20659-1-krzk@kernel.orgSigned-off-by: NKrzysztof Kozlowski <krzk@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

After commit 1d0fd57a ("logfs: remove from tree"), logfs was
removed, drop CONFIG_LOGFS from all defconfigs.

Link: http://lkml.kernel.org/r/20190530021032.190639-1-wangkefeng.wang@huawei.comSigned-off-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Here are some of the more common spelling mistakes and typos that I've
found while fixing up spelling mistakes in the kernel over the past few
months.  Developers keep on coming up with more inventive ways to spell
words.

Link: http://lkml.kernel.org/r/20190618134807.9729-1-colin.king@canonical.comSigned-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The manpage for modprobe mentions that dashes and underscores are
treated interchangeably in module names.  The stack trace dumps seem to
print module names with underscores.  Use bash to replace _ with the
pattern [-_] so that file names with dashes or underscores can be found.

For example, this line:
[   27.919759]  hda_widget_sysfs_init+0x2b8/0x3a5 [snd_hda_core]

should find a module named snd-hda-core.ko.

Link: http://lkml.kernel.org/r/20190531205926.42474-1-evgreen@chromium.orgSigned-off-by: NEvan Green <evgreen@chromium.org>
Reviewed-by: NDouglas Anderson <dianders@chromium.org>
Acked-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Evan Green <evgreen@chromium.org>
Cc: Nicolas Boichat <drinkcat@chromium.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Manuel Traut <manut@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Misspelling 'prohibited' is quite common in the real world, although
surprisingly not so much in the Linux Kernel.  In addition to fixing the
typo we may as well add it to the spelling checker.

Also adding the present participle (prohibiting).

Link: http://lkml.kernel.org/r/20190514153341.22540-1-chris.paterson2@renesas.com
Fixes: 5bf2fbbe ("clk: renesas: cpg-mssr: Add r8a77470 support")
Signed-off-by: NChris Paterson <chris.paterson2@renesas.com>
Acked-by: NStephen Boyd <sboyd@kernel.org>
Acked-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The RISC-V architecture has a register named the "Supervisor Exception
Program Counter", or "sepc".  This abbreviation triggers checkpatch.pl's
misspelling detector, resulting in noise in the checkpatch output.  The
risk that this noise could cause more useful warnings to be missed seems
to outweigh the harm of an occasional misspelling of "spec".  Thus drop
the "sepc" entry from the misspelling list.

[akpm@linux-foundation.org: fix existing "sepc" instances, per Joe]
Link: http://lkml.kernel.org/r/20190518210037.13674-1-paul.walmsley@sifive.comSigned-off-by: NPaul Walmsley <paul.walmsley@sifive.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>

In Chromium OS kernel builds, we split the debug information as .ko.debug
files, and that's what decode_stacktrace.sh needs to use.

Relax objfile matching rule to allow any .ko* file to be matched.

[drinkcat@chromium.org: add quotes around name pattern]
  Link: http://lkml.kernel.org/r/20190528103346.42720-1-drinkcat@chromium.org
Link: http://lkml.kernel.org/r/20190521234148.64060-1-drinkcat@chromium.orgSigned-off-by: NNicolas Boichat <drinkcat@chromium.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The basepath may contain special characters, which would confuse the regex
matcher.  ${var#prefix} does the right thing.

Link: http://lkml.kernel.org/r/20190518055946.181563-1-drinkcat@chromium.org
Fixes: 67a28de4 ("scripts/decode_stacktrace: only strip base path when a prefix of the path")
Signed-off-by: NNicolas Boichat <drinkcat@chromium.org>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are a few macros in IOMMU have single-char identifiers make the code
hard to read and debug.  Replace them with meaningful names.

Link: http://lkml.kernel.org/r/1559566783-13627-1-git-send-email-cai@lca.pwSigned-off-by: NQian Cai <cai@lca.pw>
Suggested-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change my email since lab.ntt.co.jp email domain has been deprecated due
to company policy.

Link: http://lkml.kernel.org/r/1562495153-8166-1-git-send-email-konishi.ryusuke@gmail.comSigned-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>

cpu_to_le32/le32_to_cpu is defined in include/linux/byteorder/generic.h,
which is not exported to user-space.

UAPI headers must use the ones prefixed with double-underscore.

Detected by compile-testing exported headers:

  include/linux/nilfs2_ondisk.h: In function `nilfs_checkpoint_set_snapshot':
  include/linux/nilfs2_ondisk.h:536:17: error: implicit declaration of function `cpu_to_le32' [-Werror=implicit-function-declaration]
    cp->cp_flags = cpu_to_le32(le32_to_cpu(cp->cp_flags) |  \
                   ^
  include/linux/nilfs2_ondisk.h:552:1: note: in expansion of macro `NILFS_CHECKPOINT_FNS'
   NILFS_CHECKPOINT_FNS(SNAPSHOT, snapshot)
   ^~~~~~~~~~~~~~~~~~~~
  include/linux/nilfs2_ondisk.h:536:29: error: implicit declaration of function `le32_to_cpu' [-Werror=implicit-function-declaration]
    cp->cp_flags = cpu_to_le32(le32_to_cpu(cp->cp_flags) |  \
                               ^
  include/linux/nilfs2_ondisk.h:552:1: note: in expansion of macro `NILFS_CHECKPOINT_FNS'
   NILFS_CHECKPOINT_FNS(SNAPSHOT, snapshot)
   ^~~~~~~~~~~~~~~~~~~~
  include/linux/nilfs2_ondisk.h: In function `nilfs_segment_usage_set_clean':
  include/linux/nilfs2_ondisk.h:622:19: error: implicit declaration of function `cpu_to_le64' [-Werror=implicit-function-declaration]
    su->su_lastmod = cpu_to_le64(0);
                     ^~~~~~~~~~~

Link: http://lkml.kernel.org/r/20190605053006.14332-1-yamada.masahiro@socionext.com
Fixes: e63e88bc ("nilfs2: move ioctl interface and disk layout to uapi separately")
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NRyusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Cc: <stable@vger.kernel.org>	[4.9+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Following zsmalloc.c's example we call trylock_page() and unlock_page().
Also make z3fold_page_migrate() assert that newpage is passed in locked,
as per the documentation.

[akpm@linux-foundation.org: fix trylock_page return value test, per Shakeel]
Link: http://lkml.kernel.org/r/20190702005122.41036-1-henryburns@google.com
Link: http://lkml.kernel.org/r/20190702233538.52793-1-henryburns@google.comSigned-off-by: NHenry Burns <henryburns@google.com>
Suggested-by: NVitaly Wool <vitalywool@gmail.com>
Acked-by: NVitaly Wool <vitalywool@gmail.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Reviewed-by: NShakeel Butt <shakeelb@google.com>
Cc: Vitaly Vul <vitaly.vul@sony.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Xidong Wang <wangxidong_97@163.com>
Cc: Jonathan Adams <jwadams@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When we calculate total statistics for memcg1_stats and memcg1_events,
we use the the index 'i' in the for loop as the events index.  Actually
we should use memcg1_stats[i] and memcg1_events[i] as the events index.

Link: http://lkml.kernel.org/r/1562116978-19539-1-git-send-email-laoar.shao@gmail.com
Fixes: 42a30035 ("mm: memcontrol: fix recursive statistics correctness & scalabilty").
Signed-off-by: Yafang Shao <laoar.shao@gmail.com
Reviewed-by: NShakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Yafang Shao <shaoyafang@didiglobal.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Architectures like powerpc use different address range to map ioremap
and vmalloc range.  The memunmap() check used by the nvdimm layer was
wrongly using is_vmalloc_addr() to check for ioremap range which fails
for ppc64.  This result in ppc64 not freeing the ioremap mapping.  The
side effect of this is an unbind failure during module unload with
papr_scm nvdimm driver

Link: http://lkml.kernel.org/r/20190701134038.14165-1-aneesh.kumar@linux.ibm.comSigned-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Fixes: b5beae5e ("powerpc/pseries: Add driver for PAPR SCM regions")
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When file refaults are detected and there are many inactive file pages,
the system never reclaim anonymous pages, the file pages are dropped
aggressively when there are still a lot of cold anonymous pages and
system thrashes.  This issue impacts the performance of applications
with large executable, e.g.  chrome.

With this patch, when file refault is detected, inactive_list_is_low()
always returns true for file pages in get_scan_count() to enable
scanning anonymous pages.

The problem can be reproduced by the following test program.

---8<---
void fallocate_file(const char *filename, off_t size)
{
	struct stat st;
	int fd;

	if (!stat(filename, &st) && st.st_size >= size)
		return;

	fd = open(filename, O_WRONLY | O_CREAT, 0600);
	if (fd < 0) {
		perror("create file");
		exit(1);
	}
	if (posix_fallocate(fd, 0, size)) {
		perror("fallocate");
		exit(1);
	}
	close(fd);
}

long *alloc_anon(long size)
{
	long *start = malloc(size);
	memset(start, 1, size);
	return start;
}

long access_file(const char *filename, long size, long rounds)
{
	int fd, i;
	volatile char *start1, *end1, *start2;
	const int page_size = getpagesize();
	long sum = 0;

	fd = open(filename, O_RDONLY);
	if (fd == -1) {
		perror("open");
		exit(1);
	}

	/*
	 * Some applications, e.g. chrome, use a lot of executable file
	 * pages, map some of the pages with PROT_EXEC flag to simulate
	 * the behavior.
	 */
	start1 = mmap(NULL, size / 2, PROT_READ | PROT_EXEC, MAP_SHARED,
		      fd, 0);
	if (start1 == MAP_FAILED) {
		perror("mmap");
		exit(1);
	}
	end1 = start1 + size / 2;

	start2 = mmap(NULL, size / 2, PROT_READ, MAP_SHARED, fd, size / 2);
	if (start2 == MAP_FAILED) {
		perror("mmap");
		exit(1);
	}

	for (i = 0; i < rounds; ++i) {
		struct timeval before, after;
		volatile char *ptr1 = start1, *ptr2 = start2;
		gettimeofday(&before, NULL);
		for (; ptr1 < end1; ptr1 += page_size, ptr2 += page_size)
			sum += *ptr1 + *ptr2;
		gettimeofday(&after, NULL);
		printf("File access time, round %d: %f (sec)
", i,
		       (after.tv_sec - before.tv_sec) +
		       (after.tv_usec - before.tv_usec) / 1000000.0);
	}
	return sum;
}

int main(int argc, char *argv[])
{
	const long MB = 1024 * 1024;
	long anon_mb, file_mb, file_rounds;
	const char filename[] = "large";
	long *ret1;
	long ret2;

	if (argc != 4) {
		printf("usage: thrash ANON_MB FILE_MB FILE_ROUNDS
");
		exit(0);
	}
	anon_mb = atoi(argv[1]);
	file_mb = atoi(argv[2]);
	file_rounds = atoi(argv[3]);

	fallocate_file(filename, file_mb * MB);
	printf("Allocate %ld MB anonymous pages
", anon_mb);
	ret1 = alloc_anon(anon_mb * MB);
	printf("Access %ld MB file pages
", file_mb);
	ret2 = access_file(filename, file_mb * MB, file_rounds);
	printf("Print result to prevent optimization: %ld
",
	       *ret1 + ret2);
	return 0;
}
---8<---

Running the test program on 2GB RAM VM with kernel 5.2.0-rc5, the program
fills ram with 2048 MB memory, access a 200 MB file for 10 times.  Without
this patch, the file cache is dropped aggresively and every access to the
file is from disk.

  $ ./thrash 2048 200 10
  Allocate 2048 MB anonymous pages
  Access 200 MB file pages
  File access time, round 0: 2.489316 (sec)
  File access time, round 1: 2.581277 (sec)
  File access time, round 2: 2.487624 (sec)
  File access time, round 3: 2.449100 (sec)
  File access time, round 4: 2.420423 (sec)
  File access time, round 5: 2.343411 (sec)
  File access time, round 6: 2.454833 (sec)
  File access time, round 7: 2.483398 (sec)
  File access time, round 8: 2.572701 (sec)
  File access time, round 9: 2.493014 (sec)

With this patch, these file pages can be cached.

  $ ./thrash 2048 200 10
  Allocate 2048 MB anonymous pages
  Access 200 MB file pages
  File access time, round 0: 2.475189 (sec)
  File access time, round 1: 2.440777 (sec)
  File access time, round 2: 2.411671 (sec)
  File access time, round 3: 1.955267 (sec)
  File access time, round 4: 0.029924 (sec)
  File access time, round 5: 0.000808 (sec)
  File access time, round 6: 0.000771 (sec)
  File access time, round 7: 0.000746 (sec)
  File access time, round 8: 0.000738 (sec)
  File access time, round 9: 0.000747 (sec)

Checked the swap out stats during the test [1], 19006 pages swapped out
with this patch, 3418 pages swapped out without this patch. There are
more swap out, but I think it's within reasonable range when file backed
data set doesn't fit into the memory.

$ ./thrash 2000 100 2100 5 1 # ANON_MB FILE_EXEC FILE_NOEXEC ROUNDS
PROCESSES Allocate 2000 MB anonymous pages active_anon: 1613644,
inactive_anon: 348656, active_file: 892, inactive_file: 1384 (kB)
pswpout: 7972443, pgpgin: 478615246 Access 100 MB executable file pages
Access 2100 MB regular file pages File access time, round 0: 12.165,
(sec) active_anon: 1433788, inactive_anon: 478116, active_file: 17896,
inactive_file: 24328 (kB) File access time, round 1: 11.493, (sec)
active_anon: 1430576, inactive_anon: 477144, active_file: 25440,
inactive_file: 26172 (kB) File access time, round 2: 11.455, (sec)
active_anon: 1427436, inactive_anon: 476060, active_file: 21112,
inactive_file: 28808 (kB) File access time, round 3: 11.454, (sec)
active_anon: 1420444, inactive_anon: 473632, active_file: 23216,
inactive_file: 35036 (kB) File access time, round 4: 11.479, (sec)
active_anon: 1413964, inactive_anon: 471460, active_file: 31728,
inactive_file: 32224 (kB) pswpout: 7991449 (+ 19006), pgpgin: 489924366
(+ 11309120)

With 4 processes accessing non-overlapping parts of a large file, 30316
pages swapped out with this patch, 5152 pages swapped out without this
patch.  The swapout number is small comparing to pgpgin.

[1]: https://github.com/vovo/testing/blob/master/mem_thrash.c

Link: http://lkml.kernel.org/r/20190701081038.GA83398@google.com
Fixes: e9868505 ("mm,vmscan: only evict file pages when we have plenty")
Fixes: 7c5bd705 ("mm: memcg: only evict file pages when we have plenty")
Signed-off-by: NKuo-Hsin Yang <vovoy@chromium.org>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sonny Rao <sonnyrao@chromium.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>	[4.12+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull x86 fixes from Thomas Gleixner:
 "A collection of assorted fixes:

   - Fix for the pinned cr0/4 fallout which escaped all testing efforts
     because the kvm-intel module was never loaded when the kernel was
     compiled with CONFIG_PARAVIRT=n. The cr0/4 accessors are moved out
     of line and static key is now solely used in the core code and
     therefore can stay in the RO after init section. So the kvm-intel
     and other modules do not longer reference the (read only) static
     key which the module loader tried to update.

   - Prevent an infinite loop in arch_stack_walk_user() by breaking out
     of the loop once the return address is detected to be 0.

   - Prevent the int3_emulate_call() selftest from corrupting the stack
     when KASAN is enabled. KASASN clobbers more registers than covered
     by the emulated call implementation. Convert the int3_magic()
     selftest to a ASM function so the compiler cannot KASANify it.

   - Unbreak the build with old GCC versions and with the Gold linker by
     reverting the 'Move of _etext to the actual end of .text'. In both
     cases the build fails with 'Invalid absolute R_X86_64_32S
     relocation: _etext'

   - Initialize the context lock for init_mm, which was never an issue
     until the alternatives code started to use a temporary mm for
     patching.

   - Fix a build warning vs. the LOWMEM_PAGES constant where clang
     complains rightfully about a signed integer overflow in the shift
     operation by converting the operand to an ULL.

   - Adjust the misnamed ENDPROC() of common_spurious in the 32bit entry
     code"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/stacktrace: Prevent infinite loop in arch_stack_walk_user()
  x86/asm: Move native_write_cr0/4() out of line
  x86/pgtable/32: Fix LOWMEM_PAGES constant
  x86/alternatives: Fix int3_emulate_call() selftest stack corruption
  x86/entry/32: Fix ENDPROC of common_spurious
  Revert "x86/build: Move _etext to actual end of .text"
  x86/ldt: Initialize the context lock for init_mm

Pull timer fixes from Thomas Gleixner:
 "Two small fixes from the timer departement:

   - Prevent the compiler from converting the nanoseconds adjustment
     loop in the VDSO update function to a division (__udivdi3) by using
     the __iter_div_u64_rem() inline function which exists to prevent
     exactly that problem.

   - Fix the wrong argument order of the GENMASK macro in the NPCM timer
     driver"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timekeeping/vsyscall: Use __iter_div_u64_rem()
  clocksource/drivers/npcm: Fix misuse of GENMASK macro