linux.git/lib/Kconfig.debug, branch v4.19.255

random: remove ratelimiting for in-kernel unseeded randomness

2022-06-25T09:49:11+00:00

commit cc1e127bfa95b5fb2f9307e7168bf8b2b45b4c5e upstream.

The CONFIG_WARN_ALL_UNSEEDED_RANDOM debug option controls whether the
kernel warns about all unseeded randomness or just the first instance.
There's some complicated rate limiting and comparison to the previous
caller, such that even with CONFIG_WARN_ALL_UNSEEDED_RANDOM enabled,
developers still don't see all the messages or even an accurate count of
how many were missed. This is the result of basically parallel
mechanisms aimed at accomplishing more or less the same thing, added at
different points in random.c history, which sort of compete with the
first-instance-only limiting we have now.

It turns out, however, that nobody cares about the first unseeded
randomness instance of in-kernel users. The same first user has been
there for ages now, and nobody is doing anything about it. It isn't even
clear that anybody _can_ do anything about it. Most places that can do
something about it have switched over to using get_random_bytes_wait()
or wait_for_random_bytes(), which is the right thing to do, but there is
still much code that needs randomness sometimes during init, and as a
geeneral rule, if you're not using one of the _wait functions or the
readiness notifier callback, you're bound to be doing it wrong just
based on that fact alone.

So warning about this same first user that can't easily change is simply
not an effective mechanism for anything at all. Users can't do anything
about it, as the Kconfig text points out -- the problem isn't in
userspace code -- and kernel developers don't or more often can't react
to it.

Instead, show the warning for all instances when CONFIG_WARN_ALL_UNSEEDED_RANDOM
is set, so that developers can debug things need be, or if it isn't set,
don't show a warning at all.

At the same time, CONFIG_WARN_ALL_UNSEEDED_RANDOM now implies setting
random.ratelimit_disable=1 on by default, since if you care about one
you probably care about the other too. And we can clean up usage around
the related urandom_warning ratelimiter as well (whose behavior isn't
changing), so that it properly counts missed messages after the 10
message threshold is reached.

Cc: Theodore Ts'o 
Cc: Dominik Brodowski 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Greg Kroah-Hartman

ARM: 8800/1: use choice for kernel unwinders

2021-12-22T08:19:03+00:00

commit f9b58e8c7d031b0daa5c9a9ee27f5a4028ba53ac upstream.

While in theory multiple unwinders could be compiled in, it does
not make sense in practise. Use a choice to make the unwinder
selection mutually exclusive and mandatory.

Already before this commit it has not been possible to deselect
FRAME_POINTER. Remove the obsolete comment.

Furthermore, to produce a meaningful backtrace with FRAME_POINTER
enabled the kernel needs a specific function prologue:
    mov    ip, sp
    stmfd    sp!, {fp, ip, lr, pc}
    sub    fp, ip, #4

To get to the required prologue gcc uses apcs and no-sched-prolog.
This compiler options are not available on clang, and clang is not
able to generate the required prologue. Make the FRAME_POINTER
config symbol depending on !clang.

Suggested-by: Arnd Bergmann 
Signed-off-by: Stefan Agner 
Reviewed-by: Arnd Bergmann 
Signed-off-by: Russell King 
Signed-off-by: Anders Roxell 
Signed-off-by: Greg Kroah-Hartman

Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH

2021-09-26T11:39:48+00:00

[ Upstream commit 6fe26259b4884b657cbc233fb9cdade9d704976e ]

Commit 05a4a9527931 ("kernel/watchdog: split up config options") adds a
new config HARDLOCKUP_DETECTOR, which selects the non-existing config
HARDLOCKUP_DETECTOR_ARCH.

Hence, ./scripts/checkkconfigsymbols.py warns:

HARDLOCKUP_DETECTOR_ARCH Referencing files: lib/Kconfig.debug

Simply drop selecting the non-existing HARDLOCKUP_DETECTOR_ARCH.

Link: https://lkml.kernel.org/r/20210806115618.22088-1-lukas.bulwahn@gmail.com
Fixes: 05a4a9527931 ("kernel/watchdog: split up config options")
Signed-off-by: Lukas Bulwahn 
Cc: Nicholas Piggin 
Cc: Masahiro Yamada 
Cc: Babu Moger 
Cc: Don Zickus 
Cc: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

kmemleak: increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE default to 16K

2019-10-07T16:57:17+00:00

[ Upstream commit b751c52bb587ae66f773b15204ef7a147467f4c7 ]

The current default value (400) is too low on many systems (e.g.  some
ARM64 platform takes up 1000+ entries).

syzbot uses 16000 as default value, and has proved to be enough on beefy
configurations, so let's pick that value.

This consumes more RAM on boot (each entry is 160 bytes, so in total
~2.5MB of RAM), but the memory would later be freed (early_log is
__initdata).

Link: http://lkml.kernel.org/r/20190730154027.101525-1-drinkcat@chromium.org
Signed-off-by: Nicolas Boichat 
Suggested-by: Dmitry Vyukov 
Acked-by: Catalin Marinas 
Acked-by: Dmitry Vyukov 
Cc: Masahiro Yamada 
Cc: Kees Cook 
Cc: Petr Mladek 
Cc: Thomas Gleixner 
Cc: Tetsuo Handa 
Cc: Joe Lawrence 
Cc: Uladzislau Rezki 
Cc: Andy Shevchenko 
Cc: Stephen Rothwell 
Cc: Andrey Ryabinin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

lib/Kconfig.debug: fix build error without CONFIG_BLOCK

2019-05-02T07:58:53+00:00

commit ae3d6a323347940f0548bbb4b17f0bb2e9164169 upstream.

If CONFIG_TEST_KMOD is set to M, while CONFIG_BLOCK is not set, XFS and
BTRFS can not be compiled successly.

Link: http://lkml.kernel.org/r/20190410075434.35220-1-yuehaibing@huawei.com
Fixes: d9c6a72d6fa2 ("kmod: add test driver to stress test the module loader")
Signed-off-by: YueHaibing 
Reported-by: Hulk Robot 
Reviewed-by: Kees Cook 
Cc: Masahiro Yamada 
Cc: Petr Mladek 
Cc: Andy Shevchenko 
Cc: Matthew Wilcox 
Cc: Joe Lawrence 
Cc: Robin Murphy 
Cc: Luis Chamberlain 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

lib/Kconfig.debug: fix three typos in help text

2018-09-04T23:45:02+00:00

Fix three typos in CONFIG_WARN_ALL_UNSEEDED_RANDOM help text.

Link: http://lkml.kernel.org/r/20180830194505.4778-1-thibaut@sautereau.fr
Signed-off-by: Thibaut Sautereau 
Acked-by: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax

2018-08-26T18:48:42+00:00

Pull IDA updates from Matthew Wilcox:
 "A better IDA API:

      id = ida_alloc(ida, GFP_xxx);
      ida_free(ida, id);

  rather than the cumbersome ida_simple_get(), ida_simple_remove().

  The new IDA API is similar to ida_simple_get() but better named.  The
  internal restructuring of the IDA code removes the bitmap
  preallocation nonsense.

  I hope the net -200 lines of code is convincing"

* 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax: (29 commits)
  ida: Change ida_get_new_above to return the id
  ida: Remove old API
  test_ida: check_ida_destroy and check_ida_alloc
  test_ida: Convert check_ida_conv to new API
  test_ida: Move ida_check_max
  test_ida: Move ida_check_leaf
  idr-test: Convert ida_check_nomem to new API
  ida: Start new test_ida module
  target/iscsi: Allocate session IDs from an IDA
  iscsi target: fix session creation failure handling
  drm/vmwgfx: Convert to new IDA API
  dmaengine: Convert to new IDA API
  ppc: Convert vas ID allocation to new IDA API
  media: Convert entity ID allocation to new IDA API
  ppc: Convert mmu context allocation to new IDA API
  Convert net_namespace to new IDA API
  cb710: Convert to new IDA API
  rsxx: Convert to new IDA API
  osd: Convert to new IDA API
  sd: Convert to new IDA API
  ...

lib/Kconfig: remove 'default n' for tests

2018-08-22T17:52:48+00:00

It seems contributors follow the style of Kconfig entries where explicit
'default n' is present.  The default 'default' is 'n' already, thus, drop
these lines from Kconfig to make it more clear.

Link: http://lkml.kernel.org/r/20180719085131.79541-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Acked-by: Coly Li 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ida: Start new test_ida module

2018-08-22T03:54:20+00:00

Start transitioning the IDA tests into kernel space.  Framework heavily
cribbed from test_xarray.c.

Signed-off-by: Matthew Wilcox

deprecate the '__deprecated' attribute warnings entirely and for good

2018-08-18T19:19:56+00:00

We haven't had lots of deprecation warnings lately, but the rdma use of
it made them flare up again.

They are not useful.  They annoy everybody, and nobody ever does
anything about them, because it's always "somebody elses problem".  And
when people start thinking that warnings are normal, they stop looking
at them, and the real warnings that mean something go unnoticed.

If you want to get rid of a function, just get rid of it.  Convert every
user to the new world order.

And if you can't do that, then don't annoy everybody else with your
marking that says "I couldn't be bothered to fix this, so I'll just spam
everybody elses build logs with warnings about my laziness".

Make a kernelnewbies wiki page about things that could be cleaned up,
write a blog post about it, or talk to people on the mailing lists.  But
don't add warnings to the kernel build about cleanup that you think
should happen but you aren't doing yourself.

Don't.  Just don't.

Signed-off-by: Linus Torvalds