From: Josh Hunt <joh...@akamai.com>

[ Upstream commit 44d3bbb6f5e501b873218142fe08cdf62a4ac1f3 ]

We see our Nehalem machines reporting 'perfevents: irq loop stuck!' in
some cases when using perf:

perfevents: irq loop stuck!
WARNING: CPU: 0 PID: 3485 at arch/x86/events/intel/core.c:2282 
intel_pmu_handle_irq+0x37b/0x530
...
RIP: 0010:intel_pmu_handle_irq+0x37b/0x530
...
Call Trace:
<NMI>
? perf_event_nmi_handler+0x2e/0x50
? intel_pmu_save_and_restart+0x50/0x50
perf_event_nmi_handler+0x2e/0x50
nmi_handle+0x6e/0x120
default_do_nmi+0x3e/0x100
do_nmi+0x102/0x160
end_repeat_nmi+0x16/0x50
...
? native_write_msr+0x6/0x20
? native_write_msr+0x6/0x20
</NMI>
intel_pmu_enable_event+0x1ce/0x1f0
x86_pmu_start+0x78/0xa0
x86_pmu_enable+0x252/0x310
__perf_event_task_sched_in+0x181/0x190
? __switch_to_asm+0x41/0x70
? __switch_to_asm+0x35/0x70
? __switch_to_asm+0x41/0x70
? __switch_to_asm+0x35/0x70
finish_task_switch+0x158/0x260
__schedule+0x2f6/0x840
? hrtimer_start_range_ns+0x153/0x210
schedule+0x32/0x80
schedule_hrtimeout_range_clock+0x8a/0x100
? hrtimer_init+0x120/0x120
ep_poll+0x2f7/0x3a0
? wake_up_q+0x60/0x60
do_epoll_wait+0xa9/0xc0
__x64_sys_epoll_wait+0x1a/0x20
do_syscall_64+0x4e/0x110
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fdeb1e96c03
...
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: a...@kernel.org
Cc: Josh Hunt <joh...@akamai.com>
Cc: bpura...@akamai.com
Cc: mi...@redhat.com
Cc: jo...@redhat.com
Cc: t...@linutronix.de
Cc: namhy...@kernel.org
Cc: alexander.shish...@linux.intel.com
Link: 
https://lkml.kernel.org/r/1566256411-18820-1-git-send-email-joh...@akamai.com
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 arch/x86/events/intel/core.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 6179be624f357..2369ea1a1db79 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3572,6 +3572,11 @@ static u64 bdw_limit_period(struct perf_event *event, 
u64 left)
        return left;
 }
 
+static u64 nhm_limit_period(struct perf_event *event, u64 left)
+{
+       return max(left, 32ULL);
+}
+
 PMU_FORMAT_ATTR(event, "config:0-7"    );
 PMU_FORMAT_ATTR(umask, "config:8-15"   );
 PMU_FORMAT_ATTR(edge,  "config:18"     );
@@ -4550,6 +4555,7 @@ __init int intel_pmu_init(void)
                x86_pmu.pebs_constraints = intel_nehalem_pebs_event_constraints;
                x86_pmu.enable_all = intel_pmu_nhm_enable_all;
                x86_pmu.extra_regs = intel_nehalem_extra_regs;
+               x86_pmu.limit_period = nhm_limit_period;
 
                mem_attr = nhm_mem_events_attrs;
 
-- 
2.20.1



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