Re: [RFC v2] perf: Rewrite core context handling

[Ravi Bangoria]

> With this, I can run 'perf test' and perf_event_tests without any error in
> dmesg. I'll run perf fuzzer over night and see if it reports any issue.

I hit kernel crash with fuzzer. I'm yet to debug it. Here is the trace:

  BUG: kernel NULL pointer dereference, address: 0000000000000198
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: 0000 [#1] PREEMPT SMP NOPTI
  CPU: 48 PID: 0 Comm: swapper/48 Not tainted 6.0.0-rc1-perf-event-context-peter-queue+ #153
  Hardware name: Dell Inc. PowerEdge R6515/07PXPY, BIOS 2.7.3 03/31/2022
  RIP: 0010:x86_pmu_enable_event+0x3c/0x120
  Code: a0 63 82 e8 26 7c cd 00 65 8b 05 4f 29 01 7f 85 c0 75 0b 5b 5d 41 5c 41 5d c3 cc cc cc cc 48 c7 c7 84 a0 63 82 e8 04 7c cd 00 <8b> 8b 98 01 00 00 65 48 8b 2d 2e 3a 01 7f 85 c9 0f 85 9a 00 00 00
  RSP: 0018:ffffc900004e7d78 EFLAGS: 00010002
  RAX: 0000000000000030 RBX: 0000000000000000 RCX: 00000000c0010200
  RDX: 0000000000000000 RSI: ffffffff8263a084 RDI: ffffffff825d5466
  RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000006 R11: ffffc900004e7ba0 R12: ffff88bff6019c60
  R13: ffff88bff6019e60 R14: ffffffff82c35220 R15: ffffc9003ca83d38
  FS:  0000000000000000(0000) GS:ffff88bff6000000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000198 CR3: 000000407be26003 CR4: 0000000000770ee0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
  PKRU: 55555554
  Call Trace:
   <TASK>
   amd_pmu_enable_all+0x68/0xb0
   ctx_resched+0xd9/0x150
   event_function+0xb8/0x130
   ? hrtimer_start_range_ns+0x141/0x4a0
   ? perf_duration_warn+0x30/0x30
   remote_function+0x4d/0x60
   __flush_smp_call_function_queue+0xc4/0x500
   flush_smp_call_function_queue+0x11d/0x1b0
   do_idle+0x18f/0x2d0
   cpu_startup_entry+0x19/0x20
   start_secondary+0x121/0x160
   secondary_startup_64_no_verify+0xe5/0xeb
   </TASK>
  Modules linked in: nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip_set nf_tables libcrc32c n$netlink intel_rapl_msr intel_rapl_common kvm_amd kvm ipmi_ssif wmi_bmof irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel sp5100_tco rapl pcspkr acpi_ipmi ccp k10temp i2c_piix4 wmi ipmi_si acpi_power_meter vfat fat ext4 mbcache
  g200 i2c_algo_bit drm_shmem_helper drm_kms_helper sg syscopyarea nvme sysfillrect sysimgblt fb_sys_fops nvme_core ahci libahci t10_pi drm crc32c_intel tg3 crc64_rocksoft libata crc64 megaraid_sas ipmi_devintf ipmi_msghandl$r fuse
  CR2: 0000000000000198
  ---[ end trace 0000000000000000 ]---
  RIP: 0010:x86_pmu_enable_event+0x3c/0x120
  Code: a0 63 82 e8 26 7c cd 00 65 8b 05 4f 29 01 7f 85 c0 75 0b 5b 5d 41 5c 41 5d c3 cc cc cc cc 48 c7 c7 84 a0 63 82 e8 04 7c cd 00 <8b> 8b 98 01 00 00 65 48 8b 2d 2e 3a 01 7f 85 c9 0f 85 9a 00 00 00
  RSP: 0018:ffffc900004e7d78 EFLAGS: 00010002
  RAX: 0000000000000030 RBX: 0000000000000000 RCX: 00000000c0010200
  RDX: 0000000000000000 RSI: ffffffff8263a084 RDI: ffffffff825d5466
  RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000006 R11: ffffc900004e7ba0 R12: ffff88bff6019c60
  R13: ffff88bff6019e60 R14: ffffffff82c35220 R15: ffffc9003ca83d38
  FS:  0000000000000000(0000) GS:ffff88bff6000000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000198 CR3: 000000407be26003 CR4: 0000000000770ee0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
  PKRU: 55555554
  Kernel panic - not syncing: Fatal exception
  Kernel Offset: disabled
  ---[ end Kernel panic - not syncing: Fatal exception ]---