Re: perf: WARNING: kernel/events/core.c:4893 perf_mmap_close

[Vince Weaver]

On Tue, 9 Aug 2016, Alexander Shishkin wrote:

> Awesome, I'll have a look. Can you tell it it was messing around with
> intel_bts driver from the fuzzer log?

the fuzzer is messing around with the aux buffer, but this particular bug 
triggered quickly so I can't easily tell if this particular bug was doing 
things then.

This also turned up a bit later:

10772.606425] ------------[ cut here ]------------
[10772.611802] WARNING: CPU: 1 PID: 20027 at kernel/events/ring_buffer.c:539 __rb_free_aux+0x111/0x120
[10772.621856] Modules linked in: fuse binfmt_misc intel_rapl iosf_mbi x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel snd_hda_codec_hdmi aes_x86_64 lrw gf128mul glue_helper snd_hda_codec_realtek snd_hda_codec_generic ablk_helper ppdev iTCO_wdt snd_hda_intel snd_hda_codec snd_hda_core cryptd evdev iTCO_vendor_support snd_hwdep snd_pcm snd_timer snd i915 drm_kms_helper parport_pc wmi parport psmouse tpm_tis tpm_tis_core pcspkr serio_raw sg button i2c_i801 soundcore lpc_ich drm mei_me mfd_core i2c_smbus tpm mei video battery i2c_algo_bit sr_mod sd_mod cdrom ahci libahci xhci_pci libata ehci_pci xhci_hcd ehci_hcd e1000e usbcore ptp crc32c_intel scsi_mod pps_core usb_common fan thermal
[10772.699231] CPU: 1 PID: 20027 Comm: perf_fuzzer Tainted: G        W       4.8.0-rc1+ #187
[10772.708539] Hardware name: LENOVO 10AM000AUS/SHARKBAY, BIOS FBKT72AUS 01/26/2014
[10772.717011]  0000000000000000 ffff88011ea43cb0 ffffffff81437641 0000000000000000
[10772.725555]  0000000000000000 ffff88011ea43cf0 ffffffff81076bab 0000021b1ea43d48
[10772.734103]  ffff8800d0663800 ffff88011ea4b700 0000000000000000 ffff880036cf9800
[10772.742694] Call Trace:
[10772.745818]  <IRQ>  [<ffffffff81437641>] dump_stack+0x63/0x82
[10772.752579]  [<ffffffff81076bab>] __warn+0xcb/0xf0
[10772.758260]  [<ffffffff81076c9d>] warn_slowpath_null+0x1d/0x20
[10772.765049]  [<ffffffff81177121>] __rb_free_aux+0x111/0x120
[10772.771540]  [<ffffffff81177d38>] rb_free_aux+0x18/0x20
[10772.777637]  [<ffffffff81177fc0>] perf_aux_output_end+0xc0/0x110
[10772.784578]  [<ffffffff8100cadd>] bts_event_stop+0xad/0x110
[10772.791025]  [<ffffffff8100cb53>] bts_event_del+0x13/0x20
[10772.797318]  [<ffffffff8116dcec>] event_sched_out.isra.91+0xbc/0x3a0
[10772.804686]  [<ffffffff8116e01b>] group_sched_out+0x4b/0xc0
[10772.811152]  [<ffffffff8116e206>] ctx_sched_out+0x176/0x2c0
[10772.817625]  [<ffffffff8116f05f>] perf_mux_hrtimer_handler+0x10f/0x2c0
[10772.825143]  [<ffffffff8116ef50>] ? __perf_install_in_context+0x130/0x130
[10772.832935]  [<ffffffff810eb3e3>] __hrtimer_run_queues+0x103/0x300
[10772.840128]  [<ffffffff810ebbab>] hrtimer_interrupt+0xab/0x1b0
[10772.846903]  [<ffffffff810513b8>] local_apic_timer_interrupt+0x38/0x60
[10772.854429]  [<ffffffff81724ab3>] smp_trace_apic_timer_interrupt+0x63/0x120
[10772.862446]  [<ffffffff81722e32>] trace_apic_timer_interrupt+0x82/0x90
[10772.869935]  <EOI> ---[ end trace 7ff7a520eaea4ee2 ]---