This driver is for testing device private memory migration and devices
which use hmm_range_fault() to access system memory via device page tables.

Link: https://lore.kernel.org/r/20200422195028.3684-2-rcampbell@nvidia.com
Link: https://lore.kernel.org/r/20200516010424.2013-1-rcampbell@nvidia.comSigned-off-by: NRalph Campbell <rcampbell@nvidia.com>
Signed-off-by: NJérôme Glisse <jglisse@redhat.com>
Link: https://lore.kernel.org/r/20200509030225.14592-1-weiyongjun1@huawei.com
Link: https://lore.kernel.org/r/20200509030234.14747-1-weiyongjun1@huawei.comSigned-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20200511183704.GA225608@mwandaSigned-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>

s/capabilitiy/capability
Signed-off-by: NQiujun Huang <hqjagain@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1585818594-27373-1-git-send-email-hqjagain@gmail.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

CONFIG_TEST_LOCKUP=m adds module "test_lockup" that helps to make sure
that watchdogs and lockup detectors are working properly.

Depending on module parameters test_lockup could emulate soft or hard
lockup, "hung task", hold arbitrary lock, allocate bunch of pages.

Also it could generate series of lockups with cooling-down periods, in
this way it could be used as "ping" for locks or page allocator.  Loop
checks signals between iteration thus could be stopped by ^C.

# modinfo test_lockup
...
parm:           time_secs:lockup time in seconds, default 0 (uint)
parm:           time_nsecs:nanoseconds part of lockup time, default 0 (uint)
parm:           cooldown_secs:cooldown time between iterations in seconds, default 0 (uint)
parm:           cooldown_nsecs:nanoseconds part of cooldown, default 0 (uint)
parm:           iterations:lockup iterations, default 1 (uint)
parm:           all_cpus:trigger lockup at all cpus at once (bool)
parm:           state:wait in 'R' running (default), 'D' uninterruptible, 'K' killable, 'S' interruptible state (charp)
parm:           use_hrtimer:use high-resolution timer for sleeping (bool)
parm:           iowait:account sleep time as iowait (bool)
parm:           lock_read:lock read-write locks for read (bool)
parm:           lock_single:acquire locks only at one cpu (bool)
parm:           reacquire_locks:release and reacquire locks/irq/preempt between iterations (bool)
parm:           touch_softlockup:touch soft-lockup watchdog between iterations (bool)
parm:           touch_hardlockup:touch hard-lockup watchdog between iterations (bool)
parm:           call_cond_resched:call cond_resched() between iterations (bool)
parm:           measure_lock_wait:measure lock wait time (bool)
parm:           lock_wait_threshold:print lock wait time longer than this in nanoseconds, default off (ulong)
parm:           disable_irq:disable interrupts: generate hard-lockups (bool)
parm:           disable_softirq:disable bottom-half irq handlers (bool)
parm:           disable_preempt:disable preemption: generate soft-lockups (bool)
parm:           lock_rcu:grab rcu_read_lock: generate rcu stalls (bool)
parm:           lock_mmap_sem:lock mm->mmap_sem: block procfs interfaces (bool)
parm:           lock_rwsem_ptr:lock rw_semaphore at address (ulong)
parm:           lock_mutex_ptr:lock mutex at address (ulong)
parm:           lock_spinlock_ptr:lock spinlock at address (ulong)
parm:           lock_rwlock_ptr:lock rwlock at address (ulong)
parm:           alloc_pages_nr:allocate and free pages under locks (uint)
parm:           alloc_pages_order:page order to allocate (uint)
parm:           alloc_pages_gfp:allocate pages with this gfp_mask, default GFP_KERNEL (uint)
parm:           alloc_pages_atomic:allocate pages with GFP_ATOMIC (bool)
parm:           reallocate_pages:free and allocate pages between iterations (bool)

Parameters for locking by address are unsafe and taints kernel. With
CONFIG_DEBUG_SPINLOCK=y they at least check magics for embedded spinlocks.

Examples:

task hang in D-state:
modprobe test_lockup time_secs=1 iterations=60 state=D

task hang in io-wait D-state:
modprobe test_lockup time_secs=1 iterations=60 state=D iowait

softlockup:
modprobe test_lockup time_secs=1 iterations=60 state=R

hardlockup:
modprobe test_lockup time_secs=1 iterations=60 state=R disable_irq

system-wide hardlockup:
modprobe test_lockup time_secs=1 iterations=60 state=R \
 disable_irq all_cpus

rcu stall:
modprobe test_lockup time_secs=1 iterations=60 state=R \
 lock_rcu touch_softlockup

lock mmap_sem / block procfs interfaces:
modprobe test_lockup time_secs=1 iterations=60 state=S lock_mmap_sem

lock tasklist_lock for read / block forks:
TASKLIST_LOCK=$(awk '$3 == "tasklist_lock" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=R \
 disable_irq lock_read lock_rwlock_ptr=$TASKLIST_LOCK

lock namespace_sem / block vfs mount operations:
NAMESPACE_SEM=$(awk '$3 == "namespace_sem" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=S \
 lock_rwsem_ptr=$NAMESPACE_SEM

lock cgroup mutex / block cgroup operations:
CGROUP_MUTEX=$(awk '$3 == "cgroup_mutex" {print "0x"$1}' /proc/kallsyms)
modprobe test_lockup time_secs=1 iterations=60 state=S \
 lock_mutex_ptr=$CGROUP_MUTEX

ping cgroup_mutex every second and measure maximum lock wait time:
modprobe test_lockup cooldown_secs=1 iterations=60 state=S \
 lock_mutex_ptr=$CGROUP_MUTEX reacquire_locks measure_lock_wait

[linux@roeck-us.net: rename disable_irq to fix build error]
  Link: http://lkml.kernel.org/r/20200317133614.23152-1-linux@roeck-us.netSigned-off-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Dmitry Monakhov <dmtrmonakhov@yandex-team.ru
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Link: http://lkml.kernel.org/r/158132859146.2797.525923171323227836.stgit@buzzSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit ac7c3e4f ("compiler: enable CONFIG_OPTIMIZE_INLINING
forcibly") made this always-on option. We released v5.4 and v5.5
including that commit.

Remove the CONFIG option and clean up the code now.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NMiguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Reviewed-by: NNathan Chancellor <natechancellor@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Miller <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200220110807.32534-2-masahiroy@kernel.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently turning on DEBUG_INFO_SPLIT when DEBUG_INFO_BTF is also
enabled will produce invalid btf file, since gen_btf function in
link-vmlinux.sh script doesn't handle *.dwo files.

Enabling DEBUG_INFO_REDUCED will also produce invalid btf file,
and using GCC_PLUGIN_RANDSTRUCT with BTF makes no sense.

Fixes: e83b9f55 ("kbuild: add ability to generate BTF type info for vmlinux")
Reported-by: NJann Horn <jannh@google.com>
Reported-by: NLiu Yiding <liuyd.fnst@cn.fujitsu.com>
Signed-off-by: NSlava Bacherikov <slava@bacher09.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: NKees Cook <keescook@chromium.org>
Acked-by: NKP Singh <kpsingh@google.com>
Acked-by: NAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200402204138.408021-1-slava@bacher09.org

Extend lockdep to validate lock wait-type context.

The current wait-types are:

	LD_WAIT_FREE,		/* wait free, rcu etc.. */
	LD_WAIT_SPIN,		/* spin loops, raw_spinlock_t etc.. */
	LD_WAIT_CONFIG,		/* CONFIG_PREEMPT_LOCK, spinlock_t etc.. */
	LD_WAIT_SLEEP,		/* sleeping locks, mutex_t etc.. */

Where lockdep validates that the current lock (the one being acquired)
fits in the current wait-context (as generated by the held stack).

This ensures that there is no attempt to acquire mutexes while holding
spinlocks, to acquire spinlocks while holding raw_spinlocks and so on. In
other words, its a more fancy might_sleep().

Obviously RCU made the entire ordeal more complex than a simple single
value test because RCU can be acquired in (pretty much) any context and
while it presents a context to nested locks it is not the same as it
got acquired in.

Therefore its necessary to split the wait_type into two values, one
representing the acquire (outer) and one representing the nested context
(inner). For most 'normal' locks these two are the same.

[ To make static initialization easier we have the rule that:
  .outer == INV means .outer == .inner; because INV == 0. ]

It further means that its required to find the minimal .inner of the held
stack to compare against the outer of the new lock; because while 'normal'
RCU presents a CONFIG type to nested locks, if it is taken while already
holding a SPIN type it obviously doesn't relax the rules.

Below is an example output generated by the trivial test code:

  raw_spin_lock(&foo);
  spin_lock(&bar);
  spin_unlock(&bar);
  raw_spin_unlock(&foo);

 [ BUG: Invalid wait context ]
 -----------------------------
 swapper/0/1 is trying to lock:
 ffffc90000013f20 (&bar){....}-{3:3}, at: kernel_init+0xdb/0x187
 other info that might help us debug this:
 1 lock held by swapper/0/1:
  #0: ffffc90000013ee0 (&foo){+.+.}-{2:2}, at: kernel_init+0xd1/0x187

The way to read it is to look at the new -{n,m} part in the lock
description; -{3:3} for the attempted lock, and try and match that up to
the held locks, which in this case is the one: -{2,2}.

This tells that the acquiring lock requires a more relaxed environment than
presented by the lock stack.

Currently only the normal locks and RCU are converted, the rest of the
lockdep users defaults to .inner = INV which is ignored. More conversions
can be done when desired.

The check for spinlock_t nesting is not enabled by default. It's a separate
config option for now as there are known problems which are currently
addressed. The config option allows to identify these problems and to
verify that the solutions found are indeed solving them.

The config switch will be removed and the checks will permanently enabled
once the vast majority of issues has been addressed.

[ bigeasy: Move LD_WAIT_FREE,… out of CONFIG_LOCKDEP to avoid compile
	   failure with CONFIG_DEBUG_SPINLOCK + !CONFIG_LOCKDEP]
[ tglx: Add the config option ]
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200321113242.427089655@linutronix.de

To make it more obvious what almost everyone wants to set here.

Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vasiliy Khoruzhick <vasilykh@arista.com>
Cc: linux-serial@vger.kernel.org
Suggested-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NDmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200306153156.579921-1-dima@arista.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Many embedded boards have a disconnected TTL level serial which can
generate some garbage that can lead to spurious false sysrq detects.

Currently, sysrq can be either completely disabled for serial console
or always disabled (with CONFIG_MAGIC_SYSRQ_SERIAL), since
commit 732dbf3a ("serial: do not accept sysrq characters via serial port")

At Arista, we have such boards that can generate BREAK and random
garbage. While disabling sysrq for serial console would solve
the problem with spurious false sysrq triggers, it's also desirable
to have a way to enable sysrq back.

As a measure of balance between on and off options, add
MAGIC_SYSRQ_SERIAL_SEQUENCE which is a string sequence that can enable
sysrq if it follows BREAK on a serial line. The longer the string - the
less likely it may be in the garbage.

Having the way to enable sysrq was beneficial to debug lockups with
a manual investigation in field and on the other side preventing false
sysrq detections.
Based-on-patch-by: NVasiliy Khoruzhick <vasilykh@arista.com>
Signed-off-by: NDmitry Safonov <dima@arista.com>
Link: https://lore.kernel.org/r/20200302175135.269397-3-dima@arista.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Supports push, pop and converting an array into a heap. If the sense of
the compare function is inverted then it can provide a max-heap.
Based-on-work-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NIan Rogers <irogers@google.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200214075133.181299-3-irogers@google.com

This CONFIG option was added by commit 35bb5b1e ("Add option to
enable -Wframe-larger-than= on gcc 4.4"). At that time, the cc-option
check was needed.

According to Documentation/process/changes.rst, the current minimal
supported version of GCC is 4.6, so you can assume GCC supports it.
Clang supports it as well.

Remove the cc-option switch and redundant comments.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Reviewed-by: NNathan Chancellor <natechancellor@gmail.com>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>

With the realization that having debugfs enabled on "production" systems
is generally not a good idea, debugfs is being disabled from more and
more platforms over time.  However, the functionality of dynamic
debugging still is needed at times, and since it relies on debugfs for
its user api, having debugfs disabled also forces dynamic debug to be
disabled.

To get around this, also create the "control" file for dynamic_debug in
procfs.  This allows people turn on debugging as needed at runtime for
individual driverfs and subsystems.

Reported-by: many different companies
Cc: Jason Baron <jbaron@akamai.com>
Acked-by: NWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200210211142.GB1373304@kroah.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As tests are added to kunit, it will become less feasible to execute
all built tests together.  By supporting modular tests we provide
a simple way to do selective execution on a running system; specifying

CONFIG_KUNIT=y
CONFIG_KUNIT_EXAMPLE_TEST=m

...means we can simply "insmod example-test.ko" to run the tests.

To achieve this we need to do the following:

o export the required symbols in kunit
o string-stream tests utilize non-exported symbols so for now we skip
  building them when CONFIG_KUNIT_TEST=m.
o drivers/base/power/qos-test.c contains a few unexported interface
  references, namely freq_qos_read_value() and freq_constraints_init().
  Both of these could be potentially defined as static inline functions
  in include/linux/pm_qos.h, but for now we simply avoid supporting
  module build for that test suite.
o support a new way of declaring test suites.  Because a module cannot
  do multiple late_initcall()s, we provide a kunit_test_suites() macro
  to declare multiple suites within the same module at once.
o some test module names would have been too general ("test-test"
  and "example-test" for kunit tests, "inode-test" for ext4 tests);
  rename these as appropriate ("kunit-test", "kunit-example-test"
  and "ext4-inode-test" respectively).

Also define kunit_test_suite() via kunit_test_suites()
as callers in other trees may need the old definition.
Co-developed-by: NKnut Omang <knut.omang@oracle.com>
Signed-off-by: NKnut Omang <knut.omang@oracle.com>
Signed-off-by: NAlan Maguire <alan.maguire@oracle.com>
Reviewed-by: NBrendan Higgins <brendanhiggins@google.com>
Acked-by: Theodore Ts'o <tytso@mit.edu> # for ext4 bits
Acked-by: David Gow <davidgow@google.com> # For list-test
Reported-by: Nkbuild test robot <lkp@intel.com>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Some configuration items are messed up during conflict resolving.  For
example, STRICT_DEVMEM should not in testing menu, but kunit should.
This patch fixes all of them.

[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/20191209155653.7509-1-changbin.du@gmail.comSigned-off-by: NChangbin Du <changbin.du@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Let DEBUG_PREEMPT depend on CONFIG_PREEMPTION.
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20191015191821.11479-33-bigeasy@linutronix.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

Adjust indentation from spaces to tab (+optional two spaces) as in
coding style with command like:
	$ sed -e 's/^        /	/' -i */Kconfig

Link: http://lkml.kernel.org/r/20191120140140.19148-1-krzk@kernel.orgSigned-off-by: NKrzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

DEBUG_FS does not belong to 'Compile-time checks and compiler options'.

Link: http://lkml.kernel.org/r/20190909144453.3520-10-changbin.du@gmail.com
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: NChangbin Du <changbin.du@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I think DEBUG_BUGVERBOSE is a dmesg option which gives more debug info
to dmesg.

Link: http://lkml.kernel.org/r/20190909144453.3520-9-changbin.du@gmail.comSigned-off-by: NChangbin Du <changbin.du@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Create a submenu 'Scheduler Debugging' for scheduler debugging options.

Link: http://lkml.kernel.org/r/20190909144453.3520-8-changbin.du@gmail.comSigned-off-by: NChangbin Du <changbin.du@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

They are both memory debug options to debug kernel stack issues.

Link: http://lkml.kernel.org/r/20190909144453.3520-7-changbin.du@gmail.comSigned-off-by: NChangbin Du <changbin.du@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

They are similar options so place them together.

Link: http://lkml.kernel.org/r/20190909144453.3520-6-changbin.du@gmail.comSigned-off-by: NChangbin Du <changbin.du@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move error injection, coverage, testing options to a new top level
submenu 'Kernel Testing and Coverage'.  They are all for test purpose.

Link: http://lkml.kernel.org/r/20190909144453.3520-5-changbin.du@gmail.comSigned-off-by: NChangbin Du <changbin.du@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Group these similar runtime data structures verification options
together.

Link: http://lkml.kernel.org/r/20190909144453.3520-4-changbin.du@gmail.comSigned-off-by: NChangbin Du <changbin.du@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The arch special options are a little long, so create a submenu for
them.

Link: http://lkml.kernel.org/r/20190909144453.3520-3-changbin.du@gmail.comSigned-off-by: NChangbin Du <changbin.du@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "hacking: make 'kernel hacking' menu better structurized", v3.

This series is a trivial improvment for the layout of 'kernel hacking'
configuration menu.  Now we have many items in it which makes takes a
little time to look up them since they are not well structurized yet.

Early discussion is here:
  https://lkml.org/lkml/2019/9/1/39

This patch (of 9):

Group generic kernel debugging instruments sysrq/kgdb/ubsan together
into a new submenu.

Link: http://lkml.kernel.org/r/20190909144453.3520-2-changbin.du@gmail.comSigned-off-by: NChangbin Du <changbin.du@gmail.com>
Acked-by: NRandy Dunlap <rdunlap@infradead.org>
Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce user specified latency in the packet reception path
By exposing the test parameters as part of the debugfs channel
attributes. We will control the testing state via these attributes.
Signed-off-by: NBranden Bonaby <brandonbonaby94@gmail.com>
Reviewed-by: NMichael Kelley <mikelley@microsoft.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>

Currently, some sanity checks for uapi headers are done by
scripts/headers_check.pl, which is wired up to the 'headers_check'
target in the top Makefile.

It is true compiling headers has better test coverage, but there
are still several headers excluded from the compile test. I like
to keep headers_check.pl for a while, but we can delete a lot of
code by moving the build rule to usr/include/Makefile.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

Add a KUnit test for the kernel doubly linked list implementation in
include/linux/list.h

Each test case (list_test_x) is focused on testing the behaviour of the
list function/macro 'x'. None of the tests pass invalid lists to these
macros, and so should behave identically with DEBUG_LIST enabled and
disabled.

Note that, at present, it only tests the list_ types (not the
singly-linked hlist_), and does not yet test all of the
list_for_each_entry* macros (and some related things like
list_prepare_entry).

Ignoring checkpatch.pl spurious errors related to its handling of for_each
and other list macros. checkpatch.pl expects anything with for_each in its
name to be a loop and expects that the open brace is placed on the same
line as for a for loop. In this case, test case naming scheme includes
name of the macro it is testing, which results in the spurious errors.
Commit message updated by Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: NDavid Gow <davidgow@google.com>
Reviewed-by: NBrendan Higgins <brendanhiggins@google.com>
Tested-by: NBrendan Higgins <brendanhiggins@google.com>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

It has been suggested several times to extend vsnprintf() to be able
to convert the numeric value of ENOSPC to print "ENOSPC". This
implements that as a %p extension: With %pe, one can do

  if (IS_ERR(foo)) {
    pr_err("Sorry, can't do that: %pe\n", foo);
    return PTR_ERR(foo);
  }

instead of what is seen in quite a few places in the kernel:

  if (IS_ERR(foo)) {
    pr_err("Sorry, can't do that: %ld\n", PTR_ERR(foo));
    return PTR_ERR(foo);
  }

If the value passed to %pe is an ERR_PTR, but the library function
errname() added here doesn't know about the value, the value is simply
printed in decimal. If the value passed to %pe is not an ERR_PTR, we
treat it as an ordinary %p and thus print the hashed value (passing
non-ERR_PTR values to %pe indicates a bug in the caller, but we can't
do much about that).

With my embedded hat on, and because it's not very invasive to do,
I've made it possible to remove this. The errname() function and
associated lookup tables take up about 3K. For most, that's probably
quite acceptable and a price worth paying for more readable
dmesg (once this starts getting used), while for those that disable
printk() it's of very little use - I don't see a
procfs/sysfs/seq_printf() file reasonably making use of this - and
they clearly want to squeeze vmlinux as much as possible. Hence the
default y if PRINTK.

The symbols to include have been found by massaging the output of

  find arch include -iname 'errno*.h' | xargs grep -E 'define\s*E'

In the cases where some common aliasing exists
(e.g. EAGAIN=EWOULDBLOCK on all platforms, EDEADLOCK=EDEADLK on most),
I've moved the more popular one (in terms of 'git grep -w Efoo | wc)
to the bottom so that one takes precedence.

Link: http://lkml.kernel.org/r/20191015190706.15989-1-linux@rasmusvillemoes.dk
To: "Jonathan Corbet" <corbet@lwn.net>
To: linux-kernel@vger.kernel.org
Cc: "Andy Shevchenko" <andy.shevchenko@gmail.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>
Cc: "Joe Perches" <joe@perches.com>
Cc: linux-doc@vger.kernel.org
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: NUwe Kleine-König <uwe@kleine-koenig.org>
Reviewed-by: NPetr Mladek <pmladek@suse.com>
[andy.shevchenko@gmail.com: use abs()]
Acked-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NPetr Mladek <pmladek@suse.com>

KUnit tests for initialized data behavior of proc_dointvec that is
explicitly checked in the code. Includes basic parsing tests including
int min/max overflow.
Signed-off-by: NIurii Zaikin <yzaikin@google.com>
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Acked-by: NLuis Chamberlain <mcgrof@kernel.org>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

KUnit is a new unit testing framework for the kernel and when used is
built into the kernel as a part of it. Add KUnit to the lib Kconfig and
Makefile to allow it to be actually built.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Commit 9012d011 ("compiler: allow all arches to enable
CONFIG_OPTIMIZE_INLINING") allowed all architectures to enable this
option.  A couple of build errors were reported by randconfig, but all of
them have been ironed out.

Towards the goal of removing CONFIG_OPTIMIZE_INLINING entirely (and it
will simplify the 'inline' macro in compiler_types.h), this commit changes
it to always-on option.  Going forward, the compiler will always be
allowed to not inline functions marked 'inline'.

This is not a problem for x86 since it has been long used by
arch/x86/configs/{x86_64,i386}_defconfig.

I am keeping the config option just in case any problem crops up for other
architectures.

The code clean-up will be done after confirming this is solid.

Link: http://lkml.kernel.org/r/20190830034304.24259-1-yamada.masahiro@socionext.comSigned-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NNick Desaulniers <ndesaulniers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are some machines with slow disk and fast CPUs.  When they are under
memory pressure, it could take a long time to swap before the OOM kicks in
to free up some memory.  As the results, it needs a large mem pool for
kmemleak or suffering from higher chance of a kmemleak metadata allocation
failure.  524288 proves to be the good number for all architectures here.
Increase the upper bound to 1M to leave some room for the future.

Link: http://lkml.kernel.org/r/1565807572-26041-1-git-send-email-cai@lca.pwSigned-off-by: NQian Cai <cai@lca.pw>
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 kmemleak uses a static early_log buffer to trace all memory
allocation/freeing before the slab allocator is initialised.  Such early
log is replayed during kmemleak_init() to properly initialise the kmemleak
metadata for objects allocated up that point.  With a memory pool that
does not rely on the slab allocator, it is possible to skip this early log
entirely.

In order to remove the early logging, consider kmemleak_enabled == 1 by
default while the kmem_cache availability is checked directly on the
object_cache and scan_area_cache variables.  The RCU callback is only
invoked after object_cache has been initialised as we wouldn't have any
concurrent list traversal before this.

In order to reduce the number of callbacks before kmemleak is fully
initialised, move the kmemleak_init() call to mm_init().

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: remove WARN_ON(), per Catalin]
Link: http://lkml.kernel.org/r/20190812160642.52134-4-catalin.marinas@arm.comSigned-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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.orgSigned-off-by: NNicolas Boichat <drinkcat@chromium.org>
Suggested-by: NDmitry Vyukov <dvyukov@google.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NDmitry Vyukov <dvyukov@google.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When CONFIG_MODULES is disabled, CONFIG_UNUSED_SYMBOLS is pointless,
thus it should be invisible.

Instead of adding "depends on MODULES", I moved it to the sub-menu
"Enable loadable module support", which is a better fit. I put it
close to TRIM_UNUSED_KSYMS because it depends on !UNUSED_SYMBOLS.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NJessica Yu <jeyu@kernel.org>

While descending directories, Kbuild produces objects for modules,
but do not link final *.ko files; it is done in the modpost.

To keep track of modules, Kbuild creates a *.mod file in $(MODVERDIR)
for every module it is building. Some post-processing steps read the
necessary information from *.mod files. This avoids descending into
directories again. This mechanism was introduced in 2003 or so.

Later, commit 551559e1 ("kbuild: implement modules.order") added
modules.order. So, we can simply read it out to know all the modules
with directory paths. This is easier than parsing the first line of
*.mod files.

$(MODVERDIR) has a flat directory structure, that is, *.mod files
are named only with base names. This is based on the assumption that
the module name is unique across the tree. This assumption is really
fragile.

Stephen Rothwell reported a race condition caused by a module name
conflict:

  https://lkml.org/lkml/2019/5/13/991

In parallel building, two different threads could write to the same
$(MODVERDIR)/*.mod simultaneously.

Non-unique module names are the source of all kind of troubles, hence
commit 3a48a919 ("kbuild: check uniqueness of module names")
introduced a new checker script.

However, it is still fragile in the build system point of view because
this race happens before scripts/modules-check.sh is invoked. If it
happens again, the modpost will emit unclear error messages.

To fix this issue completely, create *.mod with full directory path
so that two threads never attempt to write to the same file.

$(MODVERDIR) is no longer needed.

Since modules with directory paths are listed in modules.order, Kbuild
is still able to find *.mod files without additional descending.

I also killed cmd_secanalysis; scripts/mod/sumversion.c computes MD4 hash
for modules with MODULE_VERSION(). When CONFIG_DEBUG_SECTION_MISMATCH=y,
it occurs not only in the modpost stage, but also during directory
descending, where sumversion.c may parse stale *.mod files. It would emit
'No such file or directory' warning when an object consisting a module is
renamed, or when a single-obj module is turned into a multi-obj module or
vice versa.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NNicolas Pitre <nico@fluxnic.net>

Add tests for heap and pagealloc initialization.  These can be used to
check init_on_alloc and init_on_free implementations as well as other
approaches to initialization.

Expected test output in the case the kernel provides heap initialization
(e.g.  when running with either init_on_alloc=1 or init_on_free=1):

  test_meminit: all 10 tests in test_pages passed
  test_meminit: all 40 tests in test_kvmalloc passed
  test_meminit: all 60 tests in test_kmemcache passed
  test_meminit: all 10 tests in test_rcu_persistent passed
  test_meminit: all 120 tests passed!

Link: http://lkml.kernel.org/r/20190529123812.43089-4-glider@google.comSigned-off-by: NAlexander Potapenko <glider@google.com>
Acked-by: NKees Cook <keescook@chromium.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Sandeep Patil <sspatil@android.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert the locking documents to ReST and add them to the
kernel development book where it belongs.

Most of the stuff here is just to make Sphinx to properly
parse the text file, as they're already in good shape,
not requiring massive changes in order to be parsed.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: NFederico Vaga <federico.vaga@vaga.pv.it>

Since this is not really a device with all capabilities, this test
ensures that it has *enough* to make it through the data path
without causing unwanted side-effects (read crash!).
Signed-off-by: NMahesh Bandewar <maheshb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A Reed-Solomon code with minimum distance d can correct any error and
erasure pattern that satisfies 2 * #error + #erasures < d. If the
error correction capacity is exceeded, then correct decoding cannot be
guaranteed. The decoder must, however, return a valid codeword or report
failure.

There are two main tests:

- Check for correct behaviour up to the error correction capacity
- Check for correct behaviour beyond error corrupted capacity

Both tests are simple:

1. Generate random data
2. Encode data with the chosen code
3. Add errors and erasures to data
4. Decode the corrupted word
5. Check for correct behaviour

When testing up to capacity we test for:

- Correct decoding
- Correct return value (i.e. the number of corrected symbols)
- That the returned error positions are correct

There are two kinds of erasures; the erased symbol can be corrupted or
not. When counting the number of corrected symbols, erasures without
symbol corruption should not be counted. Similarly, the returned error
positions should only include positions where a correction is necessary.

We run the up to capacity tests for three different interfaces of
decode_rs:

- Use the correction buffers
- Use the correction buffers with syndromes provided by the caller
- Error correction in place (does not check the error positions)

When testing beyond capacity test for silent failures. A silent failure is
when the decoder returns success but the returned word is not a valid
codeword.

There are a couple of options for the tests:

- Verbosity.

- Whether to test for correct behaviour beyond capacity. Default is to
  test beyond capacity.

- Whether to allow erasures without symbol corruption. Defaults to yes.

Note that the tests take a couple of minutes to complete.
Signed-off-by: NFerdinand Blomqvist <ferdinand.blomqvist@gmail.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190620141039.9874-2-ferdinand.blomqvist@gmail.com