Messages in this thread | | | From | Vince Weaver <> | Date | Tue, 8 Sep 2015 11:32:46 -0400 (EDT) | Subject | Re: perf: fuzzer PEBS record without PEBS event! crash |
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On Mon, 7 Sep 2015, Stephane Eranian wrote:
> On Mon, Sep 7, 2015 at 2:44 AM, Vince Weaver <vincent.weaver@maine.edu> wrote: > > On Sun, 6 Sep 2015, Stephane Eranian wrote: > > > >> > [ 1800.285152] ------------[ cut here ]------------ > >> > [ 1800.290757] WARNING: CPU: 0 PID: 0 at arch/x86/kernel/cpu/perf_event_intel_ds.c:1210 intel_pmu_drain_pebs_nhm+0x305/0x320() > >> > [ 1800.303301] PEBS record without PEBS event! status=2 pebs_enabled=1 active_mask=200000000 > >> > [ 1800.311916] Modules linked in: binfmt_misc intel_rapl iosf_mbi x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec_hdmi hmac drbg ansi_cprng i915 aesni_intel aes_x86_64 snd_hda_codec_realtek snd_hda_codec_generic lrw snd_hda_intel snd_hda_codec iTCO_wdt gf128mul drm_kms_helper snd_hda_core ppdev iTCO_vendor_support evdev glue_helper ablk_helper cryptd parport_pc snd_hwdep snd_pcm snd_timer psmouse tpm_tis tpm drm i2c_algo_bit sg parport snd pcspkr video serio_raw processor soundcore mei_me lpc_ich mfd_core mei i2c_i801 wmi button battery sr_mod sd_mod cdrom ehci_pci ehci_hcd xhci_pci xhci_hcd ahci libahci libata e1000e ptp usbcore crc32c_intel scsi_mod pps_core usb_common fan thermal > >> > [ 1800.390813] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 4.2.0+ #173 > >> > [ 1800.399488] Hardware name: LENOVO 10AM000AUS/SHARKBAY, BIOS FBKT72AUS 01/26/2014 > >> > [ 1800.408243] ffffffff81a0d828 ffff88011ea03aa8 ffffffff8169da0c ffff88011ea03af0 > >> > [ 1800.417089] ffff88011ea03ae0 ffffffff8106e812 0000000000000001 ffff880119000000 > >> > [ 1800.426024] ffff88011ea0c120 ffff88011900ffc0 ffff880119000000 ffff88011ea03b40 > >> > [ 1800.434946] Call Trace: > >> > [ 1800.438453] <IRQ> [<ffffffff8169da0c>] dump_stack+0x44/0x55 > >> > [ 1800.445504] [<ffffffff8106e812>] warn_slowpath_common+0x82/0xc0 > >> > [ 1800.452832] [<ffffffff8106e89c>] warn_slowpath_fmt+0x4c/0x50 > >> > [ 1800.459879] [<ffffffff8102f7d5>] intel_pmu_drain_pebs_nhm+0x305/0x320 > >> > [ 1800.467725] [<ffffffff810b6b69>] ? __lock_acquire.isra.31+0x349/0xfc0 > >> > [ 1800.475613] [<ffffffff8102ec38>] intel_pmu_drain_pebs_buffer+0x18/0x20 > >> > >> > >> What would help here is if you could get the source line number. You can do that > >> with gdb: > >> gdb vmlinux > >> (gdb) info line *0xffffffff8102ec38 > > > > (gdb) info line *0xffffffff8102ec38 > > Line 567 of "arch/x86/kernel/cpu/perf_event_intel_ds.c" > > starts at address 0xffffffff8102ec38 <intel_pmu_drain_pebs_buffer+24> > > and ends at 0xffffffff8102ec40 <release_pebs_buffer>. > > > > Line 567 isn't that helpful, it's just the last line of > > intel_pmu_drain_pebs_buffer() but that's possibly because I have done a > > git pull since the time I built the kernel so the source tree doesn't > > match up. > > > Do it again with the matching source tree. Addresses change all the time.
I re-compiled with current git, and the source matches the kernel exactly now. I managed to trigger the warning again (though it didn't trigger a crash yet). Still got line 567
[ 6890.067085] WARNING: CPU: 7 PID: 7 at arch/x86/kernel/cpu/perf_event_intel_ds.c:1210 intel_pmu_drain_pebs_nhm+0x305/0x320() [ 6890.078963] PEBS record without PEBS event! status=0 pebs_enabled=1 active_mask=200000001 [ 6890.199394] Call Trace: [ 6890.202024] [<ffffffff8169ffe0>] dump_stack+0x44/0x55 [ 6890.207516] [<ffffffff8106e8b2>] warn_slowpath_common+0x82/0xc0 [ 6890.213990] [<ffffffff8106e93c>] warn_slowpath_fmt+0x4c/0x50 [ 6890.220128] [<ffffffff8102f7d5>] intel_pmu_drain_pebs_nhm+0x305/0x320 [ 6890.227092] [<ffffffff8102ec38>] intel_pmu_drain_pebs_buffer+0x18/0x20
(gdb) info line *0xffffffff8102ec38 Line 567 of "arch/x86/kernel/cpu/perf_event_intel_ds.c" starts at address 0xffffffff8102ec38 <intel_pmu_drain_pebs_buffer+24> and ends at 0xffffffff8102ec40 <release_pebs_buffer>.
which is
562:static inline void intel_pmu_drain_pebs_buffer(void) 563:{ 564: struct pt_regs regs; 565: 566: x86_pmu.drain_pebs(®s); 567: }
which seems odd, though I guess because it is inlined?
Vince
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