Commit 168829ad authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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

Pull locking updates from Ingo Molnar:
 "The main changes in this cycle were:

   - A comprehensive rewrite of the robust/PI futex code's exit handling
     to fix various exit races. (Thomas Gleixner et al)

   - Rework the generic REFCOUNT_FULL implementation using
     atomic_fetch_* operations so that the performance impact of the
     cmpxchg() loops is mitigated for common refcount operations.

     With these performance improvements the generic implementation of
     refcount_t should be good enough for everybody - and this got
     confirmed by performance testing, so remove ARCH_HAS_REFCOUNT and
     REFCOUNT_FULL entirely, leaving the generic implementation enabled
     unconditionally. (Will Deacon)

   - Other misc changes, fixes, cleanups"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
  lkdtm: Remove references to CONFIG_REFCOUNT_FULL
  locking/refcount: Remove unused 'refcount_error_report()' function
  locking/refcount: Consolidate implementations of refcount_t
  locking/refcount: Consolidate REFCOUNT_{MAX,SATURATED} definitions
  locking/refcount: Move saturation warnings out of line
  locking/refcount: Improve performance of generic REFCOUNT_FULL code
  locking/refcount: Move the bulk of the REFCOUNT_FULL implementation into the <linux/refcount.h> header
  locking/refcount: Remove unused refcount_*_checked() variants
  locking/refcount: Ensure integer operands are treated as signed
  locking/refcount: Define constants for saturation and max refcount values
  futex: Prevent exit livelock
  futex: Provide distinct return value when owner is exiting
  futex: Add mutex around futex exit
  futex: Provide state handling for exec() as well
  futex: Sanitize exit state handling
  futex: Mark the begin of futex exit explicitly
  futex: Set task::futex_state to DEAD right after handling futex exit
  futex: Split futex_mm_release() for exit/exec
  exit/exec: Seperate mm_release()
  futex: Replace PF_EXITPIDONE with a state
  ...
parents 1ae78780 500543c5

arch/Kconfig

+0 −21
Original line number Diff line number Diff line
@@ -892,27 +892,6 @@ config STRICT_MODULE_RWX 
config ARCH_HAS_PHYS_TO_DMA

	bool



config ARCH_HAS_REFCOUNT

	bool

	help

	  An architecture selects this when it has implemented refcount_t

	  using open coded assembly primitives that provide an optimized

	  refcount_t implementation, possibly at the expense of some full

	  refcount state checks of CONFIG_REFCOUNT_FULL=y.



	  The refcount overflow check behavior, however, must be retained.

	  Catching overflows is the primary security concern for protecting

	  against bugs in reference counts.



config REFCOUNT_FULL

	bool "Perform full reference count validation at the expense of speed"

	help

	  Enabling this switches the refcounting infrastructure from a fast

	  unchecked atomic_t implementation to a fully state checked

	  implementation, which can be (slightly) slower but provides protections

	  against various use-after-free conditions that can be used in

	  security flaw exploits.



config HAVE_ARCH_COMPILER_H

	bool

	help

arch/arm/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -117,7 +117,6 @@ config ARM 
	select OLD_SIGSUSPEND3

	select PCI_SYSCALL if PCI

	select PERF_USE_VMALLOC

	select REFCOUNT_FULL

	select RTC_LIB

	select SYS_SUPPORTS_APM_EMULATION

	# Above selects are sorted alphabetically; please add new ones

arch/arm64/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -182,7 +182,6 @@ config ARM64 
	select PCI_SYSCALL if PCI

	select POWER_RESET

	select POWER_SUPPLY

	select REFCOUNT_FULL

	select SPARSE_IRQ

	select SWIOTLB

	select SYSCTL_EXCEPTION_TRACE

arch/s390/configs/debug_defconfig

+0 −1
Original line number Diff line number Diff line
@@ -62,7 +62,6 @@ CONFIG_OPROFILE=m 
CONFIG_KPROBES=y

CONFIG_JUMP_LABEL=y

CONFIG_STATIC_KEYS_SELFTEST=y

CONFIG_REFCOUNT_FULL=y

CONFIG_LOCK_EVENT_COUNTS=y

CONFIG_MODULES=y

CONFIG_MODULE_FORCE_LOAD=y

arch/x86/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -73,7 +73,6 @@ config X86 
	select ARCH_HAS_PMEM_API		if X86_64

	select ARCH_HAS_PTE_DEVMAP		if X86_64

	select ARCH_HAS_PTE_SPECIAL

	select ARCH_HAS_REFCOUNT

	select ARCH_HAS_UACCESS_FLUSHCACHE	if X86_64

	select ARCH_HAS_UACCESS_MCSAFE		if X86_64 && X86_MCE

	select ARCH_HAS_SET_MEMORY

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