kernel/git/stable/linux.git/lib/Kconfig.debug, branch linux-4.12.y

kernel/watchdog: Prevent false positives with turbo modes

2017-08-25T00:15:04+00:00

commit 7edaeb6841dfb27e362288ab8466ebdc4972e867 upstream. The hardlockup detector on x86 uses a performance counter based on unhalted CPU cycles and a periodic hrtimer. The hrtimer period is about 2/5 of the performance counter period, so the hrtimer should fire 2-3 times before the performance counter NMI fires. The NMI code checks whether the hrtimer fired since the last invocation. If not, it assumess a hard lockup. The calculation of those periods is based on the nominal CPU frequency. Turbo modes increase the CPU clock frequency and therefore shorten the period of the perf/NMI watchdog. With extreme Turbo-modes (3x nominal frequency) the perf/NMI period is shorter than the hrtimer period which leads to false positives. A simple fix would be to shorten the hrtimer period, but that comes with the side effect of more frequent hrtimer and softlockup thread wakeups, which is not desired. Implement a low pass filter, which checks the perf/NMI period against kernel time. If the perf/NMI fires before 4/5 of the watchdog period has elapsed then the event is ignored and postponed to the next perf/NMI. That solves the problem and avoids the overhead of shorter hrtimer periods and more frequent softlockup thread wakeups. Fixes: 58687acba592 ("lockup_detector: Combine nmi_watchdog and softlockup detector") Reported-and-tested-by: Kan Liang Signed-off-by: Thomas Gleixner Cc: dzickus@redhat.com Cc: prarit@redhat.com Cc: ak@linux.intel.com Cc: babu.moger@oracle.com Cc: peterz@infradead.org Cc: eranian@google.com Cc: acme@redhat.com Cc: atomlin@redhat.com Cc: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1708150931310.1886@nanos Signed-off-by: Greg Kroah-Hartman

lib: add module support to linked list sorting tests

2017-05-09T00:15:10+00:00

Extract the linked list sorting test code into its own source file, to allow to compile it either to a loadable module, or builtin into the kernel. Link: http://lkml.kernel.org/r/1488287219-15832-4-git-send-email-geert@linux-m68k.org Signed-off-by: Geert Uytterhoeven Reviewed-by: Andy Shevchenko Cc: Arnd Bergmann Cc: Paul Gortmaker Cc: Shuah Khan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: add module support to array-based sort tests

2017-05-09T00:15:10+00:00

Allow to compile the array-based sort test code either to a loadable module, or builtin into the kernel. Link: http://lkml.kernel.org/r/1488287219-15832-3-git-send-email-geert@linux-m68k.org Signed-off-by: Geert Uytterhoeven Reviewed-by: Andy Shevchenko Cc: Arnd Bergmann Cc: Paul Gortmaker Cc: Shuah Khan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'docs-4.12' of git://git.lwn.net/linux

2017-05-02T17:21:17+00:00

Pull documentation update from Jonathan Corbet: "A reasonably busy cycle for documentation this time around. There is a new guide for user-space API documents, rather sparsely populated at the moment, but it's a start. Markus improved the infrastructure for converting diagrams. Mauro has converted much of the USB documentation over to RST. Plus the usual set of fixes, improvements, and tweaks. There's a bit more than the usual amount of reaching out of Documentation/ to fix comments elsewhere in the tree; I have acks for those where I could get them" * tag 'docs-4.12' of git://git.lwn.net/linux: (74 commits) docs: Fix a couple typos docs: Fix a spelling error in vfio-mediated-device.txt docs: Fix a spelling error in ioctl-number.txt MAINTAINERS: update file entry for HSI subsystem Documentation: allow installing man pages to a user defined directory Doc/PM: Sync with intel_powerclamp code behavior zr364xx.rst: usb/devices is now at /sys/kernel/debug/ usb.rst: move documentation from proc_usb_info.txt to USB ReST book convert philips.txt to ReST and add to media docs docs-rst: usb: update old usbfs-related documentation arm: Documentation: update a path name docs: process/4.Coding.rst: Fix a couple of document refs docs-rst: fix usb cross-references usb: gadget.h: be consistent at kernel doc macros usb: composite.h: fix two warnings when building docs usb: get rid of some ReST doc build errors usb.rst: get rid of some Sphinx errors usb/URB.txt: convert to ReST and update it usb/persist.txt: convert to ReST and add to driver-api book usb/hotplug.txt: convert to ReST and add to driver-api book ...

lib: remove AVR32 entry in Kconfig.debug compile with frame pointers

2017-05-01T07:27:15+00:00

AVR32 architecture has been removed from the Linux kernel sources, hence clean up the architecture related symbols in lib/Kconfig.debug. Signed-off-by: Hans-Christian Noren Egtvedt

sparc64: Use LOCKDEP_SMALL, not PROVE_LOCKING_SMALL

2017-04-18T20:11:07+00:00

CONFIG_PROVE_LOCKING_SMALL shrinks the memory usage of lockdep so the kernel text, data, and bss fit in the required 32MB limit, but this option is not set for every config that enables lockdep. A 4.10 kernel fails to boot with the console output Kernel: Using 8 locked TLB entries for main kernel image. hypervisor_tlb_lock[2000000:0:8000000071c007c3:1]: errors with f Program terminated with these config options CONFIG_LOCKDEP=y CONFIG_LOCK_STAT=y CONFIG_PROVE_LOCKING=n To fix, rename CONFIG_PROVE_LOCKING_SMALL to CONFIG_LOCKDEP_SMALL, and enable this option with CONFIG_LOCKDEP=y so we get the reduced memory usage every time lockdep is turned on. Tested that CONFIG_LOCKDEP_SMALL is set to 'y' if and only if CONFIG_LOCKDEP is set to 'y'. When other lockdep-related config options that select CONFIG_LOCKDEP are enabled (e.g. CONFIG_LOCK_STAT or CONFIG_PROVE_LOCKING), verified that CONFIG_LOCKDEP_SMALL is also enabled. Fixes: e6b5f1be7afe ("config: Adding the new config parameter CONFIG_PROVE_LOCKING_SMALL for sparc") Signed-off-by: Daniel Jordan Reviewed-by: Babu Moger Signed-off-by: David S. Miller

lib/Kconfig.debug: correct documentation paths

2017-03-17T19:01:42+00:00

A bunch of documentation files have moved, correct the paths. Signed-off-by: Hans Holmberg Signed-off-by: Jonathan Corbet

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

2017-02-28T18:44:16+00:00

Pull locking fixes from Ingo Molnar: "The main change is the uninlining of large refcount_t APIs, plus a header dependency fix. Note that the uninlining allowed us to enable the underflow/overflow warnings unconditionally and remove the debug Kconfig switch: this might trigger new warnings in buggy code and turn crashes/use-after-free bugs into less harmful memory leaks" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/refcounts: Add missing kernel.h header to have UINT_MAX defined locking/refcounts: Out-of-line everything

lib: add CONFIG_TEST_SORT to enable self-test of sort()

2017-02-25T01:46:57+00:00

Along with the addition made to Kconfig.debug, the prior existing but permanently disabled test function has been slightly refactored. Patch has been tested using QEMU 2.1.2 with a .config obtained through 'make defconfig' (x86_64) and manually enabling the option. [arnd@arndb.de: move sort self-test into a separate file] Link: http://lkml.kernel.org/r/20170112110657.3123790-1-arnd@arndb.de Link: http://lkml.kernel.org/r/HE1PR09MB0394B0418D504DCD27167D4FD49B0@HE1PR09MB0394.eurprd09.prod.outlook.com Signed-off-by: Kostenzer Felix Signed-off-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: add module support to atomic64 tests

2017-02-25T01:46:57+00:00

Allow to compile the atomic64 test code either to a loadable module, or builtin into the kernel. Link: http://lkml.kernel.org/r/1483470276-10517-3-git-send-email-geert@linux-m68k.org Signed-off-by: Geert Uytterhoeven Reviewed-by: Andy Shevchenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds