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Will Deacon b90d72a6bf Revert "arm64: Enable perf events based hard lockup detector" 
This reverts commit 367c820ef0.

lockup_detector_init() makes heavy use of per-cpu variables and must be
called with preemption disabled. Usually, it's handled early during boot
in kernel_init_freeable(), before SMP has been initialised.

Since we do not know whether or not our PMU interrupt can be signalled
as an NMI until considerably later in the boot process, the Arm PMU
driver attempts to re-initialise the lockup detector off the back of a
device_initcall(). Unfortunately, this is called from preemptible
context and results in the following splat:

  | BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
  | caller is debug_smp_processor_id+0x20/0x2c
  | CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.10.0+ #276
  | Hardware name: linux,dummy-virt (DT)
  | Call trace:
  |   dump_backtrace+0x0/0x3c0
  |   show_stack+0x20/0x6c
  |   dump_stack+0x2f0/0x42c
  |   check_preemption_disabled+0x1cc/0x1dc
  |   debug_smp_processor_id+0x20/0x2c
  |   hardlockup_detector_event_create+0x34/0x18c
  |   hardlockup_detector_perf_init+0x2c/0x134
  |   watchdog_nmi_probe+0x18/0x24
  |   lockup_detector_init+0x44/0xa8
  |   armv8_pmu_driver_init+0x54/0x78
  |   do_one_initcall+0x184/0x43c
  |   kernel_init_freeable+0x368/0x380
  |   kernel_init+0x1c/0x1cc
  |   ret_from_fork+0x10/0x30

Rather than bodge this with raw_smp_processor_id() or randomly disabling
preemption, simply revert the culprit for now until we figure out how to
do this properly.

Reported-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Sumit Garg <sumit.garg@linaro.org>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/r/20201221162249.3119-1-lecopzer.chen@mediatek.com
Link: https://lore.kernel.org/r/20210112221855.10666-1-will@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2021-01-13 15:08:41 +00:00
..
boot ARM: SoC fixes for v5.11 2021-01-08 14:13:54 -08:00
configs ARM: device tree updates for 5.11 2020-12-16 16:27:35 -08:00
crypto crypto: sha - split sha.h into sha1.h and sha2.h 2020-11-20 14:45:33 +11:00
include arm64: Remove arm64_dma32_phys_limit and its uses 2021-01-12 17:49:25 +00:00
kernel Revert "arm64: Enable perf events based hard lockup detector" 2021-01-13 15:08:41 +00:00
kvm KVM/arm64 fixes for 5.11, take #1 2021-01-08 05:02:40 -05:00
lib arm64: mte: add in-kernel MTE helpers 2020-12-22 12:55:07 -08:00
mm arm64: Remove arm64_dma32_phys_limit and its uses 2021-01-12 17:49:25 +00:00
net arm64: bpf: Fix branch offset in JIT 2020-09-17 12:05:36 +01:00
xen
Kbuild
Kconfig Revert "arm64: Enable perf events based hard lockup detector" 2021-01-13 15:08:41 +00:00
Kconfig.debug arm64: remove TEXT_OFFSET randomization 2020-06-15 13:10:59 +01:00
Kconfig.platforms ARM: device tree updates for 5.11 2020-12-16 16:27:35 -08:00
Makefile arm64: link with -z norelro for LLD or aarch64-elf 2021-01-05 11:51:41 +00:00