diff options
| author | Will Deacon <will@kernel.org> | 2021-01-12 22:18:55 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-01-13 15:08:41 +0000 |
| commit | b90d72a6bfdb5e5c62cd223a8cdf4045bfbcb94d (patch) | |
| tree | 7836fa03d36ac0e9344cd2871c6e9d06bb7221ff /drivers/perf | |
| parent | df06824767cc9a32fbdb0e3d3b7e169292a5b5fe (diff) | |
Revert "arm64: Enable perf events based hard lockup detector"
This reverts commit 367c820ef08082e68df8a3bc12e62393af21e4b5.
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>
Diffstat (limited to 'drivers/perf')
| -rw-r--r-- | drivers/perf/arm_pmu.c | 5 |
1 files changed, 0 insertions, 5 deletions
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 794a37d50853..cb2f55f450e4 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -726,11 +726,6 @@ static int armpmu_get_cpu_irq(struct arm_pmu *pmu, int cpu) return per_cpu(hw_events->irq, cpu); } -bool arm_pmu_irq_is_nmi(void) -{ - return has_nmi; -} - /* * PMU hardware loses all context when a CPU goes offline. * When a CPU is hotplugged back in, since some hardware registers are |