From b61e06f258e50b25c38a73bea782bdb6876f0f70 Mon Sep 17 00:00:00 2001 From: Andrea Righi Date: Sat, 20 Sep 2008 18:02:27 +0200 Subject: [PATCH] x86, oprofile: BUG scheduling while atomic nmi_shutdown() calls unregister_die_notifier() from an atomic context after setting preempt_disable() via get_cpu_var(): [ 1049.404154] BUG: scheduling while atomic: oprofiled/7796/0x00000002 [ 1049.404171] INFO: lockdep is turned off. [ 1049.404176] Modules linked in: oprofile af_packet rfcomm l2cap kvm_intel kvm i915 drm acpi_cpufreq cpufreq_userspace cpufreq_conservative cpufreq_ondemand cpufreq_powersave freq_table container sbs sbshc dm_mod arc4 ecb cryptomgr aead snd_hda_intel crypto_blkcipher snd_pcm_oss crypto_algapi snd_pcm iwlagn iwlcore snd_timer iTCO_wdt led_class btusb iTCO_vendor_support snd psmouse bluetooth mac80211 soundcore cfg80211 snd_page_alloc intel_agp video output button battery ac dcdbas evdev ext3 jbd mbcache sg sd_mod piix ata_piix libata scsi_mod dock tg3 libphy ehci_hcd uhci_hcd usbcore thermal processor fan fuse [ 1049.404362] Pid: 7796, comm: oprofiled Not tainted 2.6.27-rc5-mm1 #30 [ 1049.404368] Call Trace: [ 1049.404384] [] thread_return+0x4a0/0x7d3 [ 1049.404396] [] generic_exec_single+0x52/0xe0 [ 1049.404405] [] generic_exec_single+0xda/0xe0 [ 1049.404414] [] smp_call_function_single+0x73/0x150 [ 1049.404423] [] schedule_timeout+0x95/0xd0 [ 1049.404430] [] wait_for_common+0x43/0x180 [ 1049.404438] [] wait_for_common+0x114/0x180 [ 1049.404448] [] default_wake_function+0x0/0x10 [ 1049.404457] [] synchronize_rcu+0x30/0x40 [ 1049.404463] [] wakeme_after_rcu+0x0/0x10 [ 1049.404472] [] _spin_unlock_irqrestore+0x40/0x80 [ 1049.404482] [] atomic_notifier_chain_unregister+0x3f/0x60 [ 1049.404501] [] nmi_shutdown+0x51/0x90 [oprofile] [ 1049.404517] [] oprofile_shutdown+0x34/0x70 [oprofile] [ 1049.404532] [] event_buffer_release+0xe/0x40 [oprofile] [ 1049.404543] [] __fput+0xcd/0x240 [ 1049.404551] [] filp_close+0x54/0x90 [ 1049.404560] [] put_files_struct+0xb1/0xd0 [ 1049.404568] [] do_exit+0x18f/0x930 [ 1049.404576] [] restore_args+0x0/0x30 [ 1049.404584] [] do_group_exit+0x36/0xa0 [ 1049.404592] [] system_call_fastpath+0x16/0x1b This can be easily triggered with 'opcontrol --shutdown'. Simply move get_cpu_var() above unregister_die_notifier(). Signed-off-by: Andrea Righi Acked-by: Robert Richter Signed-off-by: Ingo Molnar --- arch/x86/oprofile/nmi_int.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c index 0227694f7dab..8a5f1614a3d5 100644 --- a/arch/x86/oprofile/nmi_int.c +++ b/arch/x86/oprofile/nmi_int.c @@ -295,10 +295,12 @@ static void nmi_cpu_shutdown(void *dummy) static void nmi_shutdown(void) { - struct op_msrs *msrs = &get_cpu_var(cpu_msrs); + struct op_msrs *msrs; + nmi_enabled = 0; on_each_cpu(nmi_cpu_shutdown, NULL, 1); unregister_die_notifier(&profile_exceptions_nb); + msrs = &get_cpu_var(cpu_msrs); model->shutdown(msrs); free_msrs(); put_cpu_var(cpu_msrs); -- 2.20.1