Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752348AbaFECgv (ORCPT ); Wed, 4 Jun 2014 22:36:51 -0400 Received: from mga09.intel.com ([134.134.136.24]:62071 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752275AbaFECgu (ORCPT ); Wed, 4 Jun 2014 22:36:50 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.98,977,1392192000"; d="scan'208";a="551810688" Date: Thu, 5 Jun 2014 10:36:10 +0800 From: Liu ShuoX To: linux-kernel@vger.kernel.org Cc: "H. Peter Anvin" , Ingo Molnar , Peter Zijlstra , Zhang Yanmin , yanmin_zhang@linux.intel.com Subject: [PATCH] perf: fix kernel panic when parsing user space CS saved in pt_regs Message-ID: <20140605023610.GA12905@lskakaxi-intel> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zhang Yanmin We hit a kernel panic when running perf to collect some performance data. kenel is x86_64 and user space apps are 32bit. [ 71.965351, 1] [ Binder_2] BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 [ 71.965360, 1] [ Binder_2] IP: [] get_segment_base+0x71/0xc0 [ 71.965367, 1] [ Binder_2] PGD 6c65f067 PUD 0 [ 71.965375, 1] [ Binder_2] Oops: 0000 [#1] PREEMPT SMP [ 71.965413, 1] [ Binder_2] Modules linked in: ddrgx snd_merr_dpcm_wm8958 snd_intel_sst snd_soc_sst_platform snd_soc_wm8994 snd_soc_wm_hubs lm3559 imx1x5 atomisp_css2401a0_v21 libmsrlisthelper rmi4 bcm_bt_lpm videobuf_vmalloc videobuf_core fps_throttle hdmi_audio pn544(O) tngdisp bcm4335(O) cfg80211 [ 71.965420, 1] [ Binder_2] CPU: 1 PID: 304 Comm: Binder_2 Tainted: G W O 3.10.20-263902-g184bfbc-dirty #14 [ 71.965426, 1] [ Binder_2] task: ffff8800764dc300 ti: ffff88006c6e8000 task.ti: ffff88006c6e8000 [ 71.965439, 1] [ Binder_2] RIP: 0010:[] [] get_segment_base+0x71/0xc0 [ 71.965<44, 1] [ Binder_2] RSP: 0018:ffff^X8007ea87b98 EFLAGS: 00010092 [ 71.965447, 1] [ !Binder_2] RAX: 0000000000000024 RBX: 0000000000000000 RCX: 0000000000000000 [ 71.965450, 1] [ Binder_2] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000009 [ 71.965454, 1] [ Binder_2] RBP: ffff88007ea87ba8 R08: ffffffff83143b3c R09: ffffffff831848a8 [ 71.965458, 1] [ Binder_2] R10: 0000000000000000 R11: 00000000001bf2d8 R12: 0000000000000000 [ 71.965462, 1] [ Binder_2] R13: ffff88006c6e9fd8 R14: ffff88006c6e9f58 R15: ffff8800764dc300 [ 71.965468, 1_ [ Binder_2] FS: 0000000000000000(0000) GS:ffff88007ea80000(006b) knlGS:00000000f704add0 [ 71.965472, 1] [ Binder_2] CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 [ 71.965476, 1] [ Binder_2] CR2: 0000000000000004 CR3: 0000000076588000 CR4: 00000^P00001007e0 [ 71.965480, 1] [ Binder_2] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 71.965485, 1] [ Binder_2] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 71.966141, 1] [ Binder_2] Stack: [ 71.966152, 1] [ Binder_2] ffff88005f266c00 0000000000000000 ffff88007ea87c18 ffffffff82013cac [ 71.966161, 1] [ Binder_2] ffff88007ea87d58 00000016fe4704a0 00000000000001a7 ffff88007ea87ef8 [ 71.966171, 1] [ Binder_6] ffff88005f266c00 ffff88007ea87ef8 ffff8800!e07b400 ffff88005f266c00 [ 71.966173, 1] [ Binder_2] Call Trace: [ 71.966179, 1] [ Binder_2] [ 71.966190, 1] [ Binder_2] [] perf_callchain_user+0x15c/0x240 [ 71.966202, 1] [ Binder_2] [] perf_callchain+0x134/0x180 [ 71.966210, 1] [ Binder_2] [] ? local_clock+0x47/0x60 [ 71.966221, 1] [ Binder_2] [] perf_prepare_sample+0x1bb/0x240 [ 71.966231, 1] [ Binder_2] [] __perf_event_overflow+0x147/0x230 [ 71.966241, 1] [ Binder_2] [] ? x86_perf_event_set_period+0xd8/0x150 [ 71.966252, 1] [ Binder_2] [] perf_event_overflow+0x14/0x20 [ 71.966260, 1] [ Binder_2] [] intel_pmu_handle_irq+0x1c2/0x270 [ 71.966270, 1] [ Binder_2] [] ? call_softirq+0x30/0x30 [ 71.966284, 1] [ Binder_2]$ [] perf_event_nmi_handler+0x21/0x30 [ 71.966293, 1] [ Binder_2] [] nmi_handle.isr!.1+0x59/0x=0 [ 71.966303, 1] [` Binder_2] [] default_do_nmi+0x58/0x240 [ 71.966312, 1] [ " Binder_2] [] do_nmi+0xb8/0xf0 [ 71.966321, 1] [ Binder_2] [|ffffffgf828aebe7>] end_repeat_nmi+0x1e/0x2e [ 71.966332, 1] [ Binder_2] [] ? call_softirq+0x30/0x30 [ 71.966341, 1] [ Binder_2] [] ? call_softirq+0x30/0x30 [ 71.966350, 1] [ Binder_2] [] ? call_softirq+0x30/0x30 Basically, ia32 uses sysenter to start system calls. sysexit_from_sys_call=>trace_hardirqs_on_thunk. Before calling, sysexit_from_sys_call already pops up pt_regs, then trace_hardirqs_on_thunk would reuse pt_regs space. If perf NMI happens here, perf might use a bad pt_regs. The patch fixes it by moving the calling to trace_hardirqs_on_thunk ahead of the stack popup. Change-Id: I6c4fc46b009ea056f2321ce5b8f54cf8769a7bdd Signed-off-by: Zhang Yanmin --- arch/x86/ia32/ia32entry.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index 4299eb0..df61fdb 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -167,6 +167,7 @@ sysenter_dispatch: testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) jnz sysexit_audit sysexit_from_sys_call: + TRACE_IRQS_ON andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET) /* clear IF, that popfq doesn't enable interrupts early */ andl $~0x200,EFLAGS-R11(%rsp) @@ -181,7 +182,6 @@ sysexit_from_sys_call: /*CFI_RESTORE rflags*/ popq_cfi %rcx /* User %esp */ CFI_REGISTER rsp,rcx - TRACE_IRQS_ON ENABLE_INTERRUPTS_SYSEXIT32 #ifdef CONFIG_AUDITSYSCALL -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/