[powerpc/merge] PMU: Kernel warning while running pmu/ebb selftests

[Sachin Sant]

While running kernel selftests (lost_exception_test) against latest
powerpc merge/next branch code (5.16.0-rc5-03218-g798527287598)
following warning is seen:

[  172.851380] ------------[ cut here ]------------
[  172.851391] WARNING: CPU: 8 PID: 2901 at arch/powerpc/include/asm/hw_irq.h:246 power_pmu_disable+0x270/0x280
[  172.851402] Modules linked in: dm_mod bonding nft_ct nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables rfkill nfnetlink sunrpc xfs libcrc32c pseries_rng xts vmx_crypto uio_pdrv_genirq uio sch_fq_codel ip_tables ext4 mbcache jbd2 sd_mod t10_pi sg ibmvscsi ibmveth scsi_transport_srp fuse
[  172.851442] CPU: 8 PID: 2901 Comm: lost_exception_ Not tainted 5.16.0-rc5-03218-g798527287598 #2
[  172.851451] NIP:  c00000000013d600 LR: c00000000013d5a4 CTR: c00000000013b180
[  172.851458] REGS: c000000017687860 TRAP: 0700   Not tainted  (5.16.0-rc5-03218-g798527287598)
[  172.851465] MSR:  8000000000029033 <SF,EE,ME,IR,DR,RI,LE>  CR: 48004884  XER: 20040000
[  172.851482] CFAR: c00000000013d5b4 IRQMASK: 1 
[  172.851482] GPR00: c00000000013d5a4 c000000017687b00 c000000002a10600 0000000000000004 
[  172.851482] GPR04: 0000000082004000 c0000008ba08f0a8 0000000000000000 00000008b7ed0000 
[  172.851482] GPR08: 00000000446194f6 0000000000008000 c00000000013b118 c000000000d58e68 
[  172.851482] GPR12: c00000000013d390 c00000001ec54a80 0000000000000000 0000000000000000 
[  172.851482] GPR16: 0000000000000000 0000000000000000 c000000015d5c708 c0000000025396d0 
[  172.851482] GPR20: 0000000000000000 0000000000000000 c00000000a3bbf40 0000000000000003 
[  172.851482] GPR24: 0000000000000000 c0000008ba097400 c0000000161e0d00 c00000000a3bb600 
[  172.851482] GPR28: c000000015d5c700 0000000000000001 0000000082384090 c0000008ba0020d8 
[  172.851549] NIP [c00000000013d600] power_pmu_disable+0x270/0x280
[  172.851557] LR [c00000000013d5a4] power_pmu_disable+0x214/0x280
[  172.851565] Call Trace:
[  172.851568] [c000000017687b00] [c00000000013d5a4] power_pmu_disable+0x214/0x280 (unreliable)
[  172.851579] [c000000017687b40] [c0000000003403ac] perf_pmu_disable+0x4c/0x60
[  172.851588] [c000000017687b60] [c0000000003445e4] __perf_event_task_sched_out+0x1d4/0x660
[  172.851596] [c000000017687c50] [c000000000d1175c] __schedule+0xbcc/0x12a0
[  172.851602] [c000000017687d60] [c000000000d11ea8] schedule+0x78/0x140
[  172.851608] [c000000017687d90] [c0000000001a8080] sys_sched_yield+0x20/0x40
[  172.851615] [c000000017687db0] [c0000000000334dc] system_call_exception+0x18c/0x380
[  172.851622] [c000000017687e10] [c00000000000c74c] system_call_common+0xec/0x268
[  172.851629] --- interrupt: c00 at 0x7fffa9d0d2fc
[  172.851633] NIP:  00007fffa9d0d2fc LR: 0000000010001914 CTR: 0000000000000000
[  172.851638] REGS: c000000017687e80 TRAP: 0c00   Not tainted  (5.16.0-rc5-03218-g798527287598)
[  172.851643] MSR:  800000000280f033 <SF,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE>  CR: 28000288  XER: 00000000
[  172.851657] IRQMASK: 0 
[  172.851657] GPR00: 000000000000009e 00007fffe44c0b40 00007fffa9e07300 0000000000000000 
[  172.851657] GPR04: 00007fffe44c0c28 0000000000000018 000000000000000a 0000000000000008 
[  172.851657] GPR08: 0000000000000007 0000000000000000 0000000000000000 0000000000000000 
[  172.851657] GPR12: 0000000000000000 00007fffa9eaa270 0000000000000000 0000000000000000 
[  172.851657] GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 
[  172.851657] GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 
[  172.851657] GPR24: 0000000000000190 0000000000000000 00000000000186a0 00000000000f423f 
[  172.851657] GPR28: 0000000010021650 0000000000000198 0000000010020238 000000000000d446 
[  172.851711] NIP [00007fffa9d0d2fc] 0x7fffa9d0d2fc
[  172.851715] LR [0000000010001914] 0x10001914
[  172.851719] --- interrupt: c00
[  172.851722] Instruction dump:
[  172.851725] 71490001 81280078 552905ac 79290020 2fa90000 4182fe9c 4bffff88 60000000 
[  172.851735] 4bee4729 60000000 9bdf0014 4bfffe00 <0fe00000> 60000000 60000000 60000000 
[  172.851745] ---[ end trace 10a1b687c9c436f7 ]—

CONFIG_PPC_IRQ_SOFT_MASK_DEBUG is enabled for this kernel.

The code in question was last changed by following commit:

commit 2c9ac51b850d 
powerpc/perf: Fix PMU callbacks to clear pending PMI before resetting an overflown PMC

Reverting this commit helps.

Thanks
-Sachin