linux-stable.git/lib/Kconfig.debug, branch linux-5.17.y

random: remove ratelimiting for in-kernel unseeded randomness

2022-05-30T07:27:16+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

lib/Kconfig.debug: add ARCH dependency for FUNCTION_ALIGN option

2022-04-13T17:27:22+00:00

[ Upstream commit 1bf18da62106225dbc47aab41efee2aeb99caccd ]

0Day robots reported there is compiling issue for 'csky' ARCH when
CONFIG_DEBUG_FORCE_DATA_SECTION_ALIGNED is enabled [1]:

All errors (new ones prefixed by >>):

   {standard input}: Assembler messages:
>> {standard input}:2277: Error: pcrel offset for branch to .LS000B too far (0x3c)

Which was discussed in [2].  And as there is no solution for csky yet, add
some dependency for this config to limit it to several ARCHs which have no
compiling issue so far.

[1]. https://lore.kernel.org/lkml/202202271612.W32UJAj2-lkp@intel.com/
[2]. https://www.spinics.net/lists/linux-kbuild/msg30298.html

Link: https://lkml.kernel.org/r/20220304021100.GN4548@shbuild999.sh.intel.com
Reported-by: kernel test robot 
Signed-off-by: Feng Tang 
Cc: Guo Ren 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin

Merge branch 'akpm' (patches from Andrew)

2022-01-20T08:41:01+00:00

Merge more updates from Andrew Morton:
 "55 patches.

  Subsystems affected by this patch series: percpu, procfs, sysctl,
  misc, core-kernel, get_maintainer, lib, checkpatch, binfmt, nilfs2,
  hfs, fat, adfs, panic, delayacct, kconfig, kcov, and ubsan"

* emailed patches from Andrew Morton : (55 commits)
  lib: remove redundant assignment to variable ret
  ubsan: remove CONFIG_UBSAN_OBJECT_SIZE
  kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR
  lib/Kconfig.debug: make TEST_KMOD depend on PAGE_SIZE_LESS_THAN_256KB
  btrfs: use generic Kconfig option for 256kB page size limit
  arch/Kconfig: split PAGE_SIZE_LESS_THAN_256KB from PAGE_SIZE_LESS_THAN_64KB
  configs: introduce debug.config for CI-like setup
  delayacct: track delays from memory compact
  Documentation/accounting/delay-accounting.rst: add thrashing page cache and direct compact
  delayacct: cleanup flags in struct task_delay_info and functions use it
  delayacct: fix incomplete disable operation when switch enable to disable
  delayacct: support swapin delay accounting for swapping without blkio
  panic: remove oops_id
  panic: use error_report_end tracepoint on warnings
  fs/adfs: remove unneeded variable make code cleaner
  FAT: use io_schedule_timeout() instead of congestion_wait()
  hfsplus: use struct_group_attr() for memcpy() region
  nilfs2: remove redundant pointer sbufs
  fs/binfmt_elf: use PT_LOAD p_align values for static PIE
  const_structs.checkpatch: add frequently used ops structs
  ...

kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR

2022-01-20T06:52:55+00:00

Until recent versions of GCC and Clang, it was not possible to disable
KCOV instrumentation via a function attribute.  The relevant function
attribute was introduced in 540540d06e9d9 ("kcov: add
__no_sanitize_coverage to fix noinstr for all architectures").

x86 was the first architecture to want a working noinstr, and at the
time no compiler support for the attribute existed yet.  Therefore,
commit 0f1441b44e823 ("objtool: Fix noinstr vs KCOV") introduced the
ability to NOP __sanitizer_cov_*() calls in .noinstr.text.

However, this doesn't work for other architectures like arm64 and s390
that want a working noinstr per ARCH_WANTS_NO_INSTR.

At the time of 0f1441b44e823, we didn't yet have ARCH_WANTS_NO_INSTR,
but now we can move the Kconfig dependency checks to the generic KCOV
option.  KCOV will be available if:

	- architecture does not care about noinstr, OR
	- we have objtool support (like on x86), OR
	- GCC is 12.0 or newer, OR
	- Clang is 13.0 or newer.

Link: https://lkml.kernel.org/r/20211201152604.3984495-1-elver@google.com
Signed-off-by: Marco Elver 
Reviewed-by: Nathan Chancellor 
Acked-by: Peter Zijlstra (Intel) 
Cc: Mark Rutland 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: Dave Hansen 
Cc: H. Peter Anvin 
Cc: Nick Desaulniers 
Cc: Dmitry Vyukov 
Cc: Andrey Konovalov 
Cc: Catalin Marinas 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/Kconfig.debug: make TEST_KMOD depend on PAGE_SIZE_LESS_THAN_256KB

2022-01-20T06:52:55+00:00

Commit b05fbcc36be1 ("btrfs: disable build on platforms having page size
256K") disabled btrfs for configurations that used a 256kB page size.
However, it did not fully solve the problem because CONFIG_TEST_KMOD
selects CONFIG_BTRFS, which does not account for the dependency.  This
results in a Kconfig warning and the failed BUILD_BUG_ON error
returning.

  WARNING: unmet direct dependencies detected for BTRFS_FS
    Depends on [n]: BLOCK [=y] && !PPC_256K_PAGES && !PAGE_SIZE_256KB [=y]
    Selected by [m]:
    - TEST_KMOD [=m] && RUNTIME_TESTING_MENU [=y] && m && MODULES [=y] && NETDEVICES [=y] && NET_CORE [=y] && INET [=y] && BLOCK [=y]

To resolve this, add CONFIG_PAGE_SIZE_LESS_THAN_256KB as a dependency of
CONFIG_TEST_KMOD so there is no more invalid configuration or build
errors.

Link: https://lkml.kernel.org/r/20211129230141.228085-4-nathan@kernel.org
Fixes: b05fbcc36be1 ("btrfs: disable build on platforms having page size 256K")
Signed-off-by: Nathan Chancellor 
Reported-by: kernel test robot 
Cc: Chris Mason 
Cc: David Sterba 
Cc: Josef Bacik 
Cc: Luis Chamberlain 
Cc: Nick Desaulniers 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

test_hash.c: refactor into kunit

2022-01-20T06:52:54+00:00

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.net
Reviewed-by: David Gow 
Reported-by: kernel test robot 
Tested-by: David Gow 
Co-developed-by: Augusto Durães Camargo 
Signed-off-by: Augusto Durães Camargo 
Co-developed-by: Enzo Ferreira 
Signed-off-by: Enzo Ferreira 
Signed-off-by: Isabella Basso 
Cc: Brendan Higgins 
Cc: Daniel Latypov 
Cc: Geert Uytterhoeven 
Cc: Rodrigo Siqueira 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/Kconfig.debug: properly split hash test kernel entries

2022-01-20T06:52:54+00:00

Split TEST_HASH so that each entry only has one file.

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

Link: https://lkml.kernel.org/r/20211208183711.390454-5-isabbasso@riseup.net
Reviewed-by: David Gow 
Tested-by: David Gow 
Signed-off-by: Isabella Basso 
Cc: Augusto Durães Camargo 
Cc: Brendan Higgins 
Cc: Daniel Latypov 
Cc: Enzo Ferreira 
Cc: Geert Uytterhoeven 
Cc: kernel test robot 
Cc: Rodrigo Siqueira 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2021-12-09T21:23:02+00:00

No conflicts.

Signed-off-by: Jakub Kicinski

Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2021-12-09T00:06:44+00:00

Daniel Borkmann says:

====================
bpf 2021-12-08

We've added 12 non-merge commits during the last 22 day(s) which contain
a total of 29 files changed, 659 insertions(+), 80 deletions(-).

The main changes are:

1) Fix an off-by-two error in packet range markings and also add a batch of
   new tests for coverage of these corner cases, from Maxim Mikityanskiy.

2) Fix a compilation issue on MIPS JIT for R10000 CPUs, from Johan Almbladh.

3) Fix two functional regressions and a build warning related to BTF kfunc
   for modules, from Kumar Kartikeya Dwivedi.

4) Fix outdated code and docs regarding BPF's migrate_disable() use on non-
   PREEMPT_RT kernels, from Sebastian Andrzej Siewior.

5) Add missing includes in order to be able to detangle cgroup vs bpf header
   dependencies, from Jakub Kicinski.

6) Fix regression in BPF sockmap tests caused by missing detachment of progs
   from sockets when they are removed from the map, from John Fastabend.

7) Fix a missing "no previous prototype" warning in x86 JIT caused by BPF
   dispatcher, from Björn Töpel.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf: Add selftests to cover packet access corner cases
  bpf: Fix the off-by-two error in range markings
  treewide: Add missing includes masked by cgroup -> bpf dependency
  tools/resolve_btfids: Skip unresolved symbol warning for empty BTF sets
  bpf: Fix bpf_check_mod_kfunc_call for built-in modules
  bpf: Make CONFIG_DEBUG_INFO_BTF depend upon CONFIG_BPF_SYSCALL
  mips, bpf: Fix reference to non-existing Kconfig symbol
  bpf: Make sure bpf_disable_instrumentation() is safe vs preemption.
  Documentation/locking/locktypes: Update migrate_disable() bits.
  bpf, sockmap: Re-evaluate proto ops when psock is removed from sockmap
  bpf, sockmap: Attach map progs to psock early for feature probes
  bpf, x86: Fix "no previous prototype" warning
====================

Link: https://lore.kernel.org/r/20211208155125.11826-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski

net: add net device refcount tracker infrastructure

2021-12-07T00:05:07+00:00

net device are refcounted. Over the years we had numerous bugs
caused by imbalanced dev_hold() and dev_put() calls.

The general idea is to be able to precisely pair each decrement with
a corresponding prior increment. Both share a cookie, basically
a pointer to private data storing stack traces.

This patch adds dev_hold_track() and dev_put_track().

To use these helpers, each data structure owning a refcount
should also use a "netdevice_tracker" to pair the hold and put.

netdevice_tracker dev_tracker;
...
dev_hold_track(dev, &dev_tracker, GFP_ATOMIC);
...
dev_put_track(dev, &dev_tracker);

Whenever a leak happens, we will get precise stack traces
of the point dev_hold_track() happened, at device dismantle phase.

We will also get a stack trace if too many dev_put_track() for the same
netdevice_tracker are attempted.

This is guarded by CONFIG_NET_DEV_REFCNT_TRACKER option.

Signed-off-by: Eric Dumazet 
Signed-off-by: Jakub Kicinski