On Fri, Mar 15, 2013 at 9:26 AM, Stephane Eranian <eran...@google.com> wrote: > > This patch fixes a kernel crash when using precise sampling (PEBS) > after a suspend/resume. Turns out the CPU notifier code is not invoked > on CPU0 (BP). Therefore, the DS_AREA (used by PEBS) is not restored properly > by the kernel and keeps it power-on/resume value of 0 causing any PEBS > measurement to crash when running on CPU0. > > The workaround is to add a hook in the actual resume code to restore > the DS Area MSR value. It is invoked for all CPUS. So for all but CPU0, > the DS_AREA will be restored twice but this is harmless. > > Reported-by: Linus Torvalds <torva...@linux-foundation.org> > Signed-off-by: Stephane Eranian <eran...@google.com> > --- > > diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c > b/arch/x86/kernel/cpu/perf_event_intel_ds.c > index 826054a..0e9bdd3 100644 > --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c > +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c > @@ -729,3 +729,11 @@ void intel_ds_init(void) > } > } > } > + > +void perf_restore_debug_store(void) > +{ > + if (!x86_pmu.bts && !x86_pmu.pebs) > + return; > + > + init_debug_store_on_cpu(smp_processor_id()); > +}
This seems to trigger a WARN_ON during suspend/resume. [ 1479.919313] WARNING: at kernel/smp.c:244 smp_call_function_single+0x11b/0x170() [ 1479.919314] Hardware name: iMac12,1 [ 1479.919347] Modules linked in: nfsd auth_rpcgss nfs_acl lockd sunrpc ip6table_filter ip6_tables ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat_ipv4 nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack xt_CHECKSUM iptable_mangle bridge stp llc be2iscsi iscsi_boot_sysfs bnx2i cnic uio cxgb4i cxgb4 cxgb3i cxgb3 mdio libcxgbi ib_iser rdma_cm ib_addr iw_cm ib_cm ib_sa ib_mad ib_core iscsi_tcp libiscsi_tcp libiscsi rfcomm bnep scsi_transport_iscsi nls_utf8 hfsplus arc4 ath9k ath9k_common ath9k_hw ath mac80211 snd_hda_codec_hdmi snd_hda_codec_cirrus snd_hda_intel snd_hda_codec snd_hwdep vhost_net uvcvideo cfg80211 btusb tun macvtap macvlan snd_seq snd_seq_device snd_pcm coretemp bluetooth tg3 snd_page_alloc kvm_intel videobuf2_vmalloc videobuf2_memops snd_timer videobuf2_core snd crc32c_intel [ 1479.919361] kvm iTCO_wdt iTCO_vendor_support videodev rfkill ptp media ghash_clmulni_intel joydev soundcore lpc_ich pcspkr applesmc input_polldev mfd_core i2c_i801 microcode pps_core apple_bl binfmt_misc uinput hid_logitech_dj usb_storage radeon i915 ttm i2c_algo_bit drm_kms_helper drm firewire_ohci firewire_core crc_itu_t i2c_core video [ 1479.919364] Pid: 3246, comm: pm-suspend Not tainted 3.9.0-rc2+ #2 [ 1479.919364] Call Trace: [ 1479.919370] [<ffffffff8105e9df>] warn_slowpath_common+0x7f/0xc0 [ 1479.919374] [<ffffffff8131ed40>] ? __rdmsr_on_cpu+0x50/0x50 [ 1479.919376] [<ffffffff8105ea3a>] warn_slowpath_null+0x1a/0x20 [ 1479.919377] [<ffffffff810be0eb>] smp_call_function_single+0x11b/0x170 [ 1479.919379] [<ffffffff8131efd3>] wrmsr_on_cpu+0x43/0x50 [ 1479.919382] [<ffffffff81028d59>] init_debug_store_on_cpu+0x39/0x40 [ 1479.919384] [<ffffffff81029731>] perf_restore_debug_store+0x21/0x30 [ 1479.919387] [<ffffffff815363a5>] restore_processor_state+0x225/0x230 [ 1479.919390] [<ffffffff81036da7>] acpi_suspend_lowlevel+0xf7/0x120 [ 1479.919393] [<ffffffff8136075b>] acpi_suspend_enter+0x3b/0xb7 [ 1479.919395] [<ffffffff810a84ef>] suspend_devices_and_enter+0x37f/0x430 [ 1479.919397] [<ffffffff810a873a>] pm_suspend+0x19a/0x230 [ 1479.919399] [<ffffffff810a7577>] state_store+0x87/0xf0 [ 1479.919402] [<ffffffff812fba7f>] kobj_attr_store+0xf/0x20 [ 1479.919405] [<ffffffff81210078>] sysfs_write_file+0xd8/0x150 [ 1479.919408] [<ffffffff8119bccc>] vfs_write+0xac/0x180 [ 1479.919410] [<ffffffff8119c012>] sys_write+0x52/0xa0 [ 1479.919412] [<ffffffff8166369e>] ? do_page_fault+0xe/0x10 [ 1479.919414] [<ffffffff81667cd9>] system_call_fastpath+0x16/0x1b [ 1479.919415] ---[ end trace 2af7ebe5ffee87a9 ]--- [ 1479.919416] ACPI: Low-level resume complete --Parag -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/