Re: [perf] perf_fuzzer causes crash in intel_pmu_drain_pebs_nhm()

Liang, Kan
2021-02-11T21:39:10Z

On 2/11/2021 9:53 AM, Peter Zijlstra wrote:
>
> Kan, do you have time to look at this?
>
> On Thu, Jan 28, 2021 at 02:49:47PM -0500, Vince Weaver wrote:
>> On Thu, 28 Jan 2021, Vince Weaver wrote:
>>
>>> the perf_fuzzer has turned up a repeatable crash on my haswell system.
>>>
>>> addr2line is not being very helpful, it points to DECLARE_PER_CPU_FIRST.
>>> I'll investigate more when I have the chance.
>>
>> so I poked around some more.
>>
>> This seems to be caused in
>>
>> __intel_pmu_pebs_event()
>> get_next_pebs_record_by_bit() ds.c line 1639
>> get_pebs_status(at) ds.c line 1317
>> return ((struct pebs_record_nhm *)n)->status;
>>
>> where "n" has the value of 0xc0 rather than a proper pointer.
>>

The issue is pretty strange. I haven't found the root cause yet.

The base->status (aka "n") was just used in the intel_pmu_drain_pebs_nhm().
for (at = base; at < top; at += x86_pmu.pebs_record_size) {
struct pebs_record_nhm *p = at;
u64 pebs_status;

pebs_status = p->status & cpuc->pebs_enabled;
pebs_status &= mask;
Then it seems to be modified to 0xc0, and crash at get_pebs_status()
based on your investigation.
The "base" is a local variable. The ds->pebs_buffer_base is assigned to
"base" at the beginning of the function. After that, no one change it.

>> this does seem to be repetable,

I'd like to reproduce it on my machine.
Is this issue only found in a Haswell client machine?

To reproduce the issue, can I use ./perf_fuzzer under
perf_event_tests/fuzzer?
Do I need to apply any parameters with ./perf_fuzzer?

Usually how long does it take to reproduce the issue?

Thanks,
Kan

>> but fairly deep in a fuzzing run so I
>> don't have a quick reproducer. >> Vince
>>
>>
>>> [96289.009646] BUG: kernel NULL pointer dereference, address: 0000000000000150
>>> [96289.017094] #PF: supervisor read access in kernel mode
>>> [96289.022588] #PF: error_code(0x0000) - not-present page
>>> [96289.028069] PGD 0 P4D 0
>>> [96289.030796] Oops: 0000 [#1] SMP PTI
>>> [96289.034549] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 5.11.0-rc5+ #151
>>> [96289.043059] Hardware name: LENOVO 10AM000AUS/SHARKBAY, BIOS FBKT72AUS 01/26/2014
>>> [96289.050946] RIP: 0010:intel_pmu_drain_pebs_nhm+0x464/0x5f0
>>> [96289.056817] Code: 09 00 00 0f b6 c0 49 39 c4 74 2a 48 63 82 78 09 00 00 48 01 c5 48 39 6c 24 08 76 17 0f b6 05 14 70 3f 01 83 e0 0f 3c 03 77 a4 <48> 8b 85 90 00 00 00 eb 9f 31 ed 83 eb 01 83 fb 01 0f 85 30 ff ff
>>> [96289.076876] RSP: 0000:ffffffff822039e0 EFLAGS: 00010097
>>> [96289.082468] RAX: 0000000000000002 RBX: 0000000000000155 RCX: 0000000000000008
>>> [96289.090095] RDX: ffff88811ac118a0 RSI: ffffffff82203980 RDI: ffffffff82203980
>>> [96289.097746] RBP: 00000000000000c0 R08: 0000000000000000 R09: 0000000000000000
>>> [96289.105376] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
>>> [96289.113008] R13: ffffffff82203bc0 R14: ffff88801c3cf800 R15: ffffffff829814a0
>>> [96289.120671] FS: 0000000000000000(0000) GS:ffff88811ac00000(0000) knlGS:0000000000000000
>>> [96289.129346] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> [96289.135526] CR2: 0000000000000150 CR3: 000000000220c003 CR4: 00000000001706f0
>>> [96289.143159] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>> [96289.150803] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
>>> [96289.158414] Call Trace:
>>> [96289.161041] ? update_blocked_averages+0x532/0x620
>>> [96289.166152] ? update_group_capacity+0x25/0x1d0
>>> [96289.171025] ? cpumask_next_and+0x19/0x20
>>> [96289.175339] ? update_sd_lb_stats.constprop.0+0x702/0x820
>>> [96289.181105] intel_pmu_drain_pebs_buffer+0x33/0x50
>>> [96289.186259] ? x86_pmu_commit_txn+0xbc/0xf0
>>> [96289.190749] ? _raw_spin_lock_irqsave+0x1d/0x30
>>> [96289.195603] ? timerqueue_add+0x64/0xb0
>>> [96289.199720] ? update_load_avg+0x6c/0x5e0
>>> [96289.204001] ? enqueue_task_fair+0x98/0x5a0
>>> [96289.208464] ? timerqueue_del+0x1e/0x40
>>> [96289.212556] ? uncore_msr_read_counter+0x10/0x20
>>> [96289.217513] intel_pmu_pebs_disable+0x12a/0x130
>>> [96289.222324] x86_pmu_stop+0x48/0xa0
>>> [96289.226076] x86_pmu_del+0x40/0x160
>>> [96289.229813] event_sched_out.isra.0+0x81/0x1e0
>>> [96289.234602] group_sched_out.part.0+0x4f/0xc0
>>> [96289.239257] __perf_event_disable+0xef/0x1d0
>>> [96289.243831] event_function+0x8c/0xd0
>>> [96289.247785] remote_function+0x3e/0x50
>>> [96289.251797] flush_smp_call_function_queue+0x11b/0x1a0
>>> [96289.257268] flush_smp_call_function_from_idle+0x38/0x60
>>> [96289.262944] do_idle+0x15f/0x240
>>> [96289.266421] cpu_startup_entry+0x19/0x20
>>> [96289.270639] start_kernel+0x7df/0x804
>>> [96289.274558] ? apply_microcode_early.cold+0xc/0x27
>>> [96289.279678] secondary_startup_64_no_verify+0xb0/0xbb
>>> [96289.285078] Modules linked in: nf_tables libcrc32c nfnetlink intel_rapl_msr intel_rapl_common snd_hda_codec_realtek snd_hda_codec_generic snd_hda_codec_hdmi x86_pkg_temp_thermal ledtrig_audio intel_powerclamp snd_hda_intel coretemp snd_intel_dspcfg snd_hda_codec snd_hda_core kvm_intel kvm snd_hwdep irqbypass at24 snd_pcm tpm_tis crct10dif_pclmul snd_timer crc32_pclmul regmap_i2c wmi_bmof sg tpm_tis_core snd ghash_clmulni_intel tpm iTCO_wdt aesni_intel soundcore rng_core iTCO_vendor_support crypto_simd mei_me mei cryptd pcspkr evdev glue_helper binfmt_misc ip_tables x_tables autofs4 sr_mod sd_mod t10_pi cdrom i915 iosf_mbi ahci i2c_algo_bit libahci drm_kms_helper xhci_pci ehci_pci ehci_hcd libata xhci_hcd lpc_ich usbcore i2c_i801 drm crc32c_intel e1000e mfd_core scsi_mod usb_common i2c_smbus wmi fan thermal video button
>>> [96289.362498] CR2: 0000000000000150
>>> [96289.366070] ---[ end trace 80c577f99562015f ]---
>>> [96289.371007] RIP: 0010:intel_pmu_drain_pebs_nhm+0x464/0x5f0
>>> [96289.376868] Code: 09 00 00 0f b6 c0 49 39 c4 74 2a 48 63 82 78 09 00 00 48 01 c5 48 39 6c 24 08 76 17 0f b6 05 14 70 3f 01 83 e0 0f 3c 03 77 a4 <48> 8b 85 90 00 00 00 eb 9f 31 ed 83 eb 01 83 fb 01 0f 85 30 ff ff
>>> [96289.396981] RSP: 0000:ffffffff822039e0 EFLAGS: 00010097
>>> [96289.402573] RAX: 0000000000000002 RBX: 0000000000000155 RCX: 0000000000000008
>>> [96289.410226] RDX: ffff88811ac118a0 RSI: ffffffff82203980 RDI: ffffffff82203980
>>> [96289.417841] RBP: 00000000000000c0 R08: 0000000000000000 R09: 0000000000000000
>>> [96289.425461] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
>>> [96289.433122] R13: ffffffff82203bc0 R14: ffff88801c3cf800 R15: ffffffff829814a0
>>> [96289.440774] FS: 0000000000000000(0000) GS:ffff88811ac00000(0000) knlGS:0000000000000000
>>> [96289.449374] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>>> [96289.455507] CR2: 0000000000000150 CR3: 000000000220c003 CR4: 00000000001706f0
>>> [96289.463119] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>> [96289.470764] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
>>> [96289.478408] Kernel panic - not syncing: Attempted to kill the idle task!
>>> [96289.485598] Kernel Offset: disabled
>>> [96289.489355] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---
>>>
>>>
>>