intel_pmu_lbr_disable() warning cpuc->lbr_users

Found by

Severity

First Seen

Most recently Seen

Reproducible

Found On

Linux-kernel

Introduced by

Fixed in

Details

Maps to
	arch/x86/kernel/cpu/perf_event_intel_lbr.c:349 intel_pmu_lbr_disable+0xbc/0xd0()

which is
	WARN_ON_ONCE(cpuc->lbr_users < 0);

Kernel Splat

1. *** perf_fuzzer 0.31-pre *** by Vince Weaver
   
           Linux version 4.1.0+ x86_64
           Processor: Intel 6/60/3
   
           Seeding random number generator with 1435846478
           /proc/sys/kernel/perf_event_max_sample_rate currently: 3250/s
           /proc/sys/kernel/perf_event_paranoid currently: 0
           Logging perf_event_open() failures: no
           Running fsync after every syscall: no
           To reproduce, try: ./perf_fuzzer -s 30000 -r 1435846478
   
   Pid=25543, sleeping 1s
   ==================================================
   Fuzzing the following syscalls:
           mmap perf_event_open close read write ioctl fork prctl poll 
   *NOT* Fuzzing the following syscalls:
           
   Also attempting the following:
           signal-handler-on-overflow busy-instruction-loop accessing-perf-proc-and-sys-files trashing-the-mmap-page 
   *NOT* attempting the following:
           
   ==================================================
   [ 1638.697162] ------------[ cut here ]------------
   [ 1638.702578] WARNING: CPU: 2 PID: 25543 at arch/x86/kernel/cpu/perf_event_intel_lbr.c:349 intel_pmu_lbr_disable+0xbc/0xd0()
   [ 1638.714859] Modules linked in: fuse x86_pkg_temp_thermal intel_powerclamp intel_rapl iosf_mbi coretemp kvm_intel kvm snd_hda_codec_hdmi crct10dif_pclmul crc32_pclmul ghash_clmulni_intel hmac drbg i915 ansi_cprng snd_hda_codec_realtek snd_hda_codec_generic iTCO_wdt ppdev snd_hda_intel snd_hda_codec aesni_intel aes_x86_64 snd_hda_core lrw evdev snd_hwdep drm_kms_helper drm psmouse iTCO_vendor_support snd_pcm gf128mul glue_helper ablk_helper serio_raw pcspkr cryptd snd_timer i2c_i801 processor battery video snd mei_me parport_pc i2c_algo_bit button soundcore lpc_ich mfd_core tpm_tis mei parport tpm wmi sg sr_mod sd_mod cdrom ehci_pci ehci_hcd ahci libahci libata xhci_pci xhci_hcd e1000e ptp usbcore crc32c_intel fan scsi_mod pps_core usb_common thermal thermal_sys
   [ 1638.792196] CPU: 2 PID: 25543 Comm: perf_fuzzer Tainted: G        W       4.1.0+ #160
   [ 1638.801112] Hardware name: LENOVO 10AM000AUS/SHARKBAY, BIOS FBKT72AUS 01/26/2014
   [ 1638.809578]  ffffffff81a100b0 ffff8800c5f9bd58 ffffffff8169e763 0000000000000000
   [ 1638.818108]  0000000000000000 ffff8800c5f9bd98 ffffffff8106ecba 0000000000000000
   [ 1638.826633]  ffff88011ea8bd80 ffff8801185f0000 ffff8801185f0000 ffff88011ea1deb0
   [ 1638.835153] Call Trace:
   [ 1638.838258]  [] dump_stack+0x45/0x57
   [ 1638.844290]  [] warn_slowpath_common+0x8a/0xc0
   [ 1638.851186]  [] warn_slowpath_null+0x1a/0x20
   [ 1638.857921]  [] intel_pmu_lbr_disable+0xbc/0xd0
   [ 1638.864874]  [] intel_pmu_disable_event+0xc2/0x130
   [ 1638.872125]  [] ? __intel_pmu_disable_all+0x49/0x70
   [ 1638.879455]  [] x86_pmu_stop+0x75/0xd0
   [ 1638.885560]  [] perf_ioctl+0x40a/0x470
   [ 1638.891650]  [] do_vfs_ioctl+0x2ba/0x4a0
   [ 1638.897945]  [] ? vfs_read+0x11c/0x130
   [ 1638.904069]  [] ? poll_select_set_timeout+0x4d/0x70
   [ 1638.911417]  [] SyS_ioctl+0x79/0x90
   [ 1638.917295]  [] entry_SYSCALL_64_fastpath+0x16/0x7a
   [ 1638.924613] ---[ end trace e3d880444bf5705d ]---