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Filename Latest commit message Latest commit date
Jiri Olsa 16c370534d perf/core: Disable page faults when getting phys address
[ Upstream commit d3296fb372bf7497b0e5d0478c4e7a677ec6f6e9 ]

We hit following warning when running tests on kernel
compiled with CONFIG_DEBUG_ATOMIC_SLEEP=y:

 WARNING: CPU: 19 PID: 4472 at mm/gup.c:2381 __get_user_pages_fast+0x1a4/0x200
 CPU: 19 PID: 4472 Comm: dummy Not tainted 5.6.0-rc6+ #3
 RIP: 0010:__get_user_pages_fast+0x1a4/0x200
 ...
 Call Trace:
  perf_prepare_sample+0xff1/0x1d90
  perf_event_output_forward+0xe8/0x210
  __perf_event_overflow+0x11a/0x310
  __intel_pmu_pebs_event+0x657/0x850
  intel_pmu_drain_pebs_nhm+0x7de/0x11d0
  handle_pmi_common+0x1b2/0x650
  intel_pmu_handle_irq+0x17b/0x370
  perf_event_nmi_handler+0x40/0x60
  nmi_handle+0x192/0x590
  default_do_nmi+0x6d/0x150
  do_nmi+0x2f9/0x3c0
  nmi+0x8e/0xd7

While __get_user_pages_fast() is IRQ-safe, it calls access_ok(),
which warns on:

  WARN_ON_ONCE(!in_task() && !pagefault_disabled())

Peter suggested disabling page faults around __get_user_pages_fast(),
which gets rid of the warning in access_ok() call.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200407141427.3184722-1-jolsa@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-29 16:33:02 +02:00
arch powerpc/pseries: Fix MCE handling on pseries 2020-04-29 16:33:01 +02:00
block block, bfq: invoke flush_idle_tree after reparent_active_queues in pd_offline 2020-04-23 10:36:26 +02:00
certs
crypto crypto: rng - Fix a refcounting bug in crypto_rng_reset() 2020-04-17 10:50:16 +02:00
Documentation arm64: errata: Hide CTR_EL0.DIC on systems affected by Neoverse-N1 #1542419 2020-04-29 16:32:56 +02:00
drivers pwm: bcm2835: Dynamically allocate base 2020-04-29 16:33:02 +02:00
fs ceph: don't skip updating wanted caps when cap is stale 2020-04-29 16:32:58 +02:00
include KEYS: Don't write out to userspace while holding key semaphore 2020-04-23 10:36:45 +02:00
init kbuild: remove header compile test 2020-03-05 16:43:47 +01:00
ipc ipc/util.c: sysvipc_find_ipc() should increase position index 2020-04-29 16:33:00 +02:00
kernel perf/core: Disable page faults when getting phys address 2020-04-29 16:33:02 +02:00
lib lib/raid6/test: fix build on distros whose /bin/sh is not bash 2020-04-29 16:33:00 +02:00
LICENSES
mm mm, memcg: do not high throttle allocators based on wraparound 2020-04-17 10:50:17 +02:00
net net, ip_tunnel: fix interface lookup with no key 2020-04-29 16:32:55 +02:00
samples
scripts kconfig: qconf: Fix a few alignment issues 2020-04-29 16:33:00 +02:00
security KEYS: Don't write out to userspace while holding key semaphore 2020-04-23 10:36:45 +02:00
sound ASoC: Intel: atom: Take the drv->lock mutex before calling sst_send_slot_map() 2020-04-29 16:32:59 +02:00
tools selftests: kmod: fix handling test numbers above 9 2020-04-29 16:33:00 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: Check for a bad hva before dropping into the ghc slow path 2020-03-05 16:43:48 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.35 2020-04-23 10:36:46 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.