linux-stable.git/kernel/locking/lockdep.c, branch v5.2.5

locking/lockdep: Fix merging of hlocks with non-zero references

2019-07-26T07:10:20+00:00

[ Upstream commit d9349850e188b8b59e5322fda17ff389a1c0cd7d ]

The sequence

	static DEFINE_WW_CLASS(test_ww_class);

	struct ww_acquire_ctx ww_ctx;
	struct ww_mutex ww_lock_a;
	struct ww_mutex ww_lock_b;
	struct ww_mutex ww_lock_c;
	struct mutex lock_c;

	ww_acquire_init(&ww_ctx, &test_ww_class);

	ww_mutex_init(&ww_lock_a, &test_ww_class);
	ww_mutex_init(&ww_lock_b, &test_ww_class);
	ww_mutex_init(&ww_lock_c, &test_ww_class);

	mutex_init(&lock_c);

	ww_mutex_lock(&ww_lock_a, &ww_ctx);

	mutex_lock(&lock_c);

	ww_mutex_lock(&ww_lock_b, &ww_ctx);
	ww_mutex_lock(&ww_lock_c, &ww_ctx);

	mutex_unlock(&lock_c);	(*)

	ww_mutex_unlock(&ww_lock_c);
	ww_mutex_unlock(&ww_lock_b);
	ww_mutex_unlock(&ww_lock_a);

	ww_acquire_fini(&ww_ctx); (**)

will trigger the following error in __lock_release() when calling
mutex_release() at **:

	DEBUG_LOCKS_WARN_ON(depth <= 0)

The problem is that the hlock merging happening at * updates the
references for test_ww_class incorrectly to 3 whereas it should've
updated it to 4 (representing all the instances for ww_ctx and
ww_lock_[abc]).

Fix this by updating the references during merging correctly taking into
account that we can have non-zero references (both for the hlock that we
merge into another hlock or for the hlock we are merging into).

Signed-off-by: Imre Deak 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Link: https://lkml.kernel.org/r/20190524201509.9199-2-imre.deak@intel.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

locking/lockdep: Fix OOO unlock when hlocks need merging

2019-07-26T07:10:20+00:00

[ Upstream commit 8c8889d8eaf4501ae4aaf870b6f8f55db5d5109a ]

The sequence

	static DEFINE_WW_CLASS(test_ww_class);

	struct ww_acquire_ctx ww_ctx;
	struct ww_mutex ww_lock_a;
	struct ww_mutex ww_lock_b;
	struct mutex lock_c;
	struct mutex lock_d;

	ww_acquire_init(&ww_ctx, &test_ww_class);

	ww_mutex_init(&ww_lock_a, &test_ww_class);
	ww_mutex_init(&ww_lock_b, &test_ww_class);

	mutex_init(&lock_c);

	ww_mutex_lock(&ww_lock_a, &ww_ctx);

	mutex_lock(&lock_c);

	ww_mutex_lock(&ww_lock_b, &ww_ctx);

	mutex_unlock(&lock_c);		(*)

	ww_mutex_unlock(&ww_lock_b);
	ww_mutex_unlock(&ww_lock_a);

	ww_acquire_fini(&ww_ctx);

triggers the following WARN in __lock_release() when doing the unlock at *:

	DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1);

The problem is that the WARN check doesn't take into account the merging
of ww_lock_a and ww_lock_b which results in decreasing curr->lockdep_depth
by 2 not only 1.

Note that the following sequence doesn't trigger the WARN, since there
won't be any hlock merging.

	ww_acquire_init(&ww_ctx, &test_ww_class);

	ww_mutex_init(&ww_lock_a, &test_ww_class);
	ww_mutex_init(&ww_lock_b, &test_ww_class);

	mutex_init(&lock_c);
	mutex_init(&lock_d);

	ww_mutex_lock(&ww_lock_a, &ww_ctx);

	mutex_lock(&lock_c);
	mutex_lock(&lock_d);

	ww_mutex_lock(&ww_lock_b, &ww_ctx);

	mutex_unlock(&lock_d);

	ww_mutex_unlock(&ww_lock_b);
	ww_mutex_unlock(&ww_lock_a);

	mutex_unlock(&lock_c);

	ww_acquire_fini(&ww_ctx);

In general both of the above two sequences are valid and shouldn't
trigger any lockdep warning.

Fix this by taking the decrement due to the hlock merging into account
during lock release and hlock class re-setting. Merging can't happen
during lock downgrading since there won't be a new possibility to merge
hlocks in that case, so add a WARN if merging still happens then.

Signed-off-by: Imre Deak 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Cc: ville.syrjala@linux.intel.com
Link: https://lkml.kernel.org/r/20190524201509.9199-1-imre.deak@intel.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Sasha Levin

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45+00:00

Add SPDX license identifiers to all files which:

 - Have no license information of any form

 - Have EXPORT_.*_SYMBOL_GPL inside which was used in the
   initial scan/conversion to ignore the file

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

Merge tag 's390-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2019-05-06T23:42:54+00:00

Pull s390 updates from Martin Schwidefsky:

 - Support for kernel address space layout randomization

 - Add support for kernel image signature verification

 - Convert s390 to the generic get_user_pages_fast code

 - Convert s390 to the stack unwind API analog to x86

 - Add support for CPU directed interrupts for PCI devices

 - Provide support for MIO instructions to the PCI base layer, this will
   allow the use of direct PCI mappings in user space code

 - Add the basic KVM guest ultravisor interface for protected VMs

 - Add AT_HWCAP bits for several new hardware capabilities

 - Update the CPU measurement facility counter definitions to SVN 6

 - Arnds cleanup patches for his quest to get LLVM compiles working

 - A vfio-ccw update with bug fixes and support for halt and clear

 - Improvements for the hardware TRNG code

 - Another round of cleanup for the QDIO layer

 - Numerous cleanups and bug fixes

* tag 's390-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (98 commits)
  s390/vdso: drop unnecessary cc-ldoption
  s390: fix clang -Wpointer-sign warnigns in boot code
  s390: drop CONFIG_VIRT_TO_BUS
  s390: boot, purgatory: pass $(CLANG_FLAGS) where needed
  s390: only build for new CPUs with clang
  s390: simplify disabled_wait
  s390/ftrace: use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
  s390/unwind: introduce stack unwind API
  s390/opcodes: add missing instructions to the disassembler
  s390/bug: add entry size to the __bug_table section
  s390: use proper expoline sections for .dma code
  s390/nospec: rename assembler generated expoline thunks
  s390: add missing ENDPROC statements to assembler functions
  locking/lockdep: check for freed initmem in static_obj()
  s390/kernel: add support for kernel address space layout randomization (KASLR)
  s390/kernel: introduce .dma sections
  s390/sclp: do not use static sccbs
  s390/kprobes: use static buffer for insn_page
  s390/kernel: convert SYSCALL and PGM_CHECK handlers to .quad
  s390/kernel: build a relocatable kernel
  ...

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-05-06T20:50:15+00:00

Pull locking updates from Ingo Molnar:
 "Here are the locking changes in this cycle:

   - rwsem unification and simpler micro-optimizations to prepare for
     more intrusive (and more lucrative) scalability improvements in
     v5.3 (Waiman Long)

   - Lockdep irq state tracking flag usage cleanups (Frederic
     Weisbecker)

   - static key improvements (Jakub Kicinski, Peter Zijlstra)

   - misc updates, cleanups and smaller fixes"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
  locking/lockdep: Remove unnecessary unlikely()
  locking/static_key: Don't take sleeping locks in __static_key_slow_dec_deferred()
  locking/static_key: Factor out the fast path of static_key_slow_dec()
  locking/static_key: Add support for deferred static branches
  locking/lockdep: Test all incompatible scenarios at once in check_irq_usage()
  locking/lockdep: Avoid bogus Clang warning
  locking/lockdep: Generate LOCKF_ bit composites
  locking/lockdep: Use expanded masks on find_usage_*() functions
  locking/lockdep: Map remaining magic numbers to lock usage mask names
  locking/lockdep: Move valid_state() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING
  locking/rwsem: Prevent unneeded warning during locking selftest
  locking/rwsem: Optimize rwsem structure for uncontended lock acquisition
  locking/rwsem: Enable lock event counting
  locking/lock_events: Don't show pvqspinlock events on bare metal
  locking/lock_events: Make lock_events available for all archs & other locks
  locking/qspinlock_stat: Introduce generic lockevent_*() counting APIs
  locking/rwsem: Enhance DEBUG_RWSEMS_WARN_ON() macro
  locking/rwsem: Add debug check for __down_read*()
  locking/rwsem: Micro-optimize rwsem_try_read_lock_unqueued()
  locking/rwsem: Move rwsem internal function declarations to rwsem-xadd.h
  ...

Merge branch 'core-stacktrace-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-05-06T20:11:48+00:00

Pull stack trace updates from Ingo Molnar:
 "So Thomas looked at the stacktrace code recently and noticed a few
  weirdnesses, and we all know how such stories of crummy kernel code
  meeting German engineering perfection end: a 45-patch series to clean
  it all up! :-)

  Here's the changes in Thomas's words:

   'Struct stack_trace is a sinkhole for input and output parameters
    which is largely pointless for most usage sites. In fact if embedded
    into other data structures it creates indirections and extra storage
    overhead for no benefit.

    Looking at all usage sites makes it clear that they just require an
    interface which is based on a storage array. That array is either on
    stack, global or embedded into some other data structure.

    Some of the stack depot usage sites are outright wrong, but
    fortunately the wrongness just causes more stack being used for
    nothing and does not have functional impact.

    Another oddity is the inconsistent termination of the stack trace
    with ULONG_MAX. It's pointless as the number of entries is what
    determines the length of the stored trace. In fact quite some call
    sites remove the ULONG_MAX marker afterwards with or without nasty
    comments about it. Not all architectures do that and those which do,
    do it inconsistenly either conditional on nr_entries == 0 or
    unconditionally.

    The following series cleans that up by:

      1) Removing the ULONG_MAX termination in the architecture code

      2) Removing the ULONG_MAX fixups at the call sites

      3) Providing plain storage array based interfaces for stacktrace
         and stackdepot.

      4) Cleaning up the mess at the callsites including some related
         cleanups.

      5) Removing the struct stack_trace based interfaces

    This is not changing the struct stack_trace interfaces at the
    architecture level, but it removes the exposure to the generic
    code'"

* 'core-stacktrace-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits)
  x86/stacktrace: Use common infrastructure
  stacktrace: Provide common infrastructure
  lib/stackdepot: Remove obsolete functions
  stacktrace: Remove obsolete functions
  livepatch: Simplify stack trace retrieval
  tracing: Remove the last struct stack_trace usage
  tracing: Simplify stack trace retrieval
  tracing: Make ftrace_trace_userstack() static and conditional
  tracing: Use percpu stack trace buffer more intelligently
  tracing: Simplify stacktrace retrieval in histograms
  lockdep: Simplify stack trace handling
  lockdep: Remove save argument from check_prev_add()
  lockdep: Remove unused trace argument from print_circular_bug()
  drm: Simplify stacktrace handling
  dm persistent data: Simplify stack trace handling
  dm bufio: Simplify stack trace retrieval
  btrfs: ref-verify: Simplify stack trace retrieval
  dma/debug: Simplify stracktrace retrieval
  fault-inject: Simplify stacktrace retrieval
  mm/page_owner: Simplify stack trace handling
  ...

locking/lockdep: Remove unnecessary unlikely()

2019-04-29T14:11:01+00:00

DEBUG_LOCKS_WARN_ON() already contains an unlikely(), there is no need
for another one.

Signed-off-by: zhengbin 
Cc: Andrew Morton 
Cc: Linus Torvalds 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Will Deacon 
Cc: houtao1@huawei.com
Link: http://lkml.kernel.org/r/1556540791-23110-1-git-send-email-zhengbin13@huawei.com
Signed-off-by: Ingo Molnar

lockdep: Simplify stack trace handling

2019-04-29T10:37:54+00:00

Replace the indirection through struct stack_trace by using the storage
array based interfaces and storing the information is a small lockdep
specific data structure.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Cc: Andy Lutomirski 
Cc: Steven Rostedt 
Cc: Alexander Potapenko 
Cc: Alexey Dobriyan 
Cc: Andrew Morton 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: linux-mm@kvack.org
Cc: David Rientjes 
Cc: Catalin Marinas 
Cc: Dmitry Vyukov 
Cc: Andrey Ryabinin 
Cc: kasan-dev@googlegroups.com
Cc: Mike Rapoport 
Cc: Akinobu Mita 
Cc: Christoph Hellwig 
Cc: iommu@lists.linux-foundation.org
Cc: Robin Murphy 
Cc: Marek Szyprowski 
Cc: Johannes Thumshirn 
Cc: David Sterba 
Cc: Chris Mason 
Cc: Josef Bacik 
Cc: linux-btrfs@vger.kernel.org
Cc: dm-devel@redhat.com
Cc: Mike Snitzer 
Cc: Alasdair Kergon 
Cc: Daniel Vetter 
Cc: intel-gfx@lists.freedesktop.org
Cc: Joonas Lahtinen 
Cc: Maarten Lankhorst 
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie 
Cc: Jani Nikula 
Cc: Rodrigo Vivi 
Cc: Tom Zanussi 
Cc: Miroslav Benes 
Cc: linux-arch@vger.kernel.org
Link: https://lkml.kernel.org/r/20190425094802.891724020@linutronix.de

lockdep: Remove save argument from check_prev_add()

2019-04-29T10:37:53+00:00

There is only one caller which hands in save_trace as function pointer.

Signed-off-by: Thomas Gleixner 
Reviewed-by: Josh Poimboeuf 
Acked-by: Peter Zijlstra (Intel) 
Cc: Andy Lutomirski 
Cc: Steven Rostedt 
Cc: Alexander Potapenko 
Cc: Alexey Dobriyan 
Cc: Andrew Morton 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: linux-mm@kvack.org
Cc: David Rientjes 
Cc: Catalin Marinas 
Cc: Dmitry Vyukov 
Cc: Andrey Ryabinin 
Cc: kasan-dev@googlegroups.com
Cc: Mike Rapoport 
Cc: Akinobu Mita 
Cc: Christoph Hellwig 
Cc: iommu@lists.linux-foundation.org
Cc: Robin Murphy 
Cc: Marek Szyprowski 
Cc: Johannes Thumshirn 
Cc: David Sterba 
Cc: Chris Mason 
Cc: Josef Bacik 
Cc: linux-btrfs@vger.kernel.org
Cc: dm-devel@redhat.com
Cc: Mike Snitzer 
Cc: Alasdair Kergon 
Cc: Daniel Vetter 
Cc: intel-gfx@lists.freedesktop.org
Cc: Joonas Lahtinen 
Cc: Maarten Lankhorst 
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie 
Cc: Jani Nikula 
Cc: Rodrigo Vivi 
Cc: Tom Zanussi 
Cc: Miroslav Benes 
Cc: linux-arch@vger.kernel.org
Link: https://lkml.kernel.org/r/20190425094802.803362058@linutronix.de

lockdep: Remove unused trace argument from print_circular_bug()

2019-04-29T10:37:53+00:00

Signed-off-by: Thomas Gleixner 
Reviewed-by: Josh Poimboeuf 
Cc: Andy Lutomirski 
Cc: Steven Rostedt 
Cc: Alexander Potapenko 
Cc: Alexey Dobriyan 
Cc: Andrew Morton 
Cc: Christoph Lameter 
Cc: Pekka Enberg 
Cc: linux-mm@kvack.org
Cc: David Rientjes 
Cc: Catalin Marinas 
Cc: Dmitry Vyukov 
Cc: Andrey Ryabinin 
Cc: kasan-dev@googlegroups.com
Cc: Mike Rapoport 
Cc: Akinobu Mita 
Cc: Christoph Hellwig 
Cc: iommu@lists.linux-foundation.org
Cc: Robin Murphy 
Cc: Marek Szyprowski 
Cc: Johannes Thumshirn 
Cc: David Sterba 
Cc: Chris Mason 
Cc: Josef Bacik 
Cc: linux-btrfs@vger.kernel.org
Cc: dm-devel@redhat.com
Cc: Mike Snitzer 
Cc: Alasdair Kergon 
Cc: Daniel Vetter 
Cc: intel-gfx@lists.freedesktop.org
Cc: Joonas Lahtinen 
Cc: Maarten Lankhorst 
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie 
Cc: Jani Nikula 
Cc: Rodrigo Vivi 
Cc: Tom Zanussi 
Cc: Miroslav Benes 
Cc: linux-arch@vger.kernel.org
Link: https://lkml.kernel.org/r/20190425094802.716274532@linutronix.de