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linux/drivers/perf
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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
..
hisilicon drivers/perf: hisi: Add identifier sysfs file 2020-11-25 15:10:35 +00:00
Kconfig driver/perf: Add PMU driver for the ARM DMC-620 memory controller 2020-11-25 14:51:21 +00:00
Makefile driver/perf: Add PMU driver for the ARM DMC-620 memory controller 2020-11-25 14:51:21 +00:00
arm-cci.c
…
arm-ccn.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
arm-cmn.c perf: arm-cmn: Fix conversion specifiers for node type 2020-10-01 22:30:07 +01:00
arm_dmc620_pmu.c driver/perf: Add PMU driver for the ARM DMC-620 memory controller 2020-11-25 14:51:21 +00:00
arm_dsu_pmu.c perf: remove duplicate check on fwnode 2020-11-25 15:02:08 +00:00
arm_pmu.c Revert "arm64: Enable perf events based hard lockup detector" 2021-01-13 15:08:41 +00:00
arm_pmu_acpi.c
…
arm_pmu_platform.c
…
arm_smmuv3_pmu.c perf/smmuv3: Support sysfs identifier file 2020-11-25 15:10:35 +00:00
arm_spe_pmu.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
fsl_imx8_ddr_perf.c perf/imx_ddr: Add system PMU identifier for userspace 2020-12-09 14:14:02 +00:00
qcom_l2_pmu.c
…
qcom_l3_pmu.c
…
thunderx2_pmu.c drivers/perf: thunderx2_pmu: Fix memory resource error handling 2020-09-18 14:34:51 +01:00
xgene_pmu.c drivers/perf: xgene_pmu: Fix uninitialized resource struct 2020-09-18 14:34:51 +01:00