From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yijing Wang Subject: Re: [Patch Part1 V2 12/17] iommu/vt-d: fix invalid memory access when freeing DMAR irq Date: Mon, 2 Dec 2013 09:47:02 +0800 Message-ID: <529BE696.6070206@huawei.com> References: <1385715030-20553-1-git-send-email-jiang.liu@linux.intel.com> <1385715030-20553-14-git-send-email-jiang.liu@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1385715030-20553-14-git-send-email-jiang.liu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Jiang Liu , Yinghai Lu , Joerg Roedel , David Woodhouse , Dan Williams , Vinod Koul , Ashok Raj Cc: dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: iommu@lists.linux-foundation.org Reviewed-by: Yijing Wang On 2013/11/29 16:50, Jiang Liu wrote: > In function free_dmar_iommu(), it sets IRQ handler data to NULL > before calling free_irq(), which will cause invalid memory access > because free_irq() will access IRQ handler data when calling > function dmar_msi_mask(). So only set IRQ handler data to NULL > after calling free_irq(). > > Sample stack dump: > [ 13.094010] BUG: unable to handle kernel NULL pointer dereference at 0000000000000048 > [ 13.103215] IP: [] __lock_acquire+0x4d/0x12a0 > [ 13.110104] PGD 0 > [ 13.112614] Oops: 0000 [#1] SMP > [ 13.116585] Modules linked in: > [ 13.120260] CPU: 60 PID: 1 Comm: swapper/0 Tainted: G W 3.13.0-rc1-gerry+ #9 > [ 13.129367] Hardware name: Intel Corporation LH Pass ........../SVRBD-ROW_T, BIOS SE5C600.86B.99.99.x059.091020121352 09/10/2012 > [ 13.142555] task: ffff88042dd38010 ti: ffff88042dd32000 task.ti: ffff88042dd32000 > [ 13.151179] RIP: 0010:[] [] __lock_acquire+0x4d/0x12a0 > [ 13.160867] RSP: 0000:ffff88042dd33b78 EFLAGS: 00010046 > [ 13.166969] RAX: 0000000000000046 RBX: 0000000000000002 RCX: 0000000000000000 > [ 13.175122] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000048 > [ 13.183274] RBP: ffff88042dd33bd8 R08: 0000000000000002 R09: 0000000000000001 > [ 13.191417] R10: 0000000000000000 R11: 0000000000000001 R12: ffff88042dd38010 > [ 13.199571] R13: 0000000000000000 R14: 0000000000000048 R15: 0000000000000000 > [ 13.207725] FS: 0000000000000000(0000) GS:ffff88103f200000(0000) knlGS:0000000000000000 > [ 13.217014] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 13.223596] CR2: 0000000000000048 CR3: 0000000001a0b000 CR4: 00000000000407e0 > [ 13.231747] Stack: > [ 13.234160] 0000000000000004 0000000000000046 ffff88042dd33b98 ffffffff810a567d > [ 13.243059] ffff88042dd33c08 ffffffff810bb14c ffffffff828995a0 0000000000000046 > [ 13.251969] 0000000000000000 0000000000000000 0000000000000002 0000000000000000 > [ 13.260862] Call Trace: > [ 13.263775] [] ? trace_hardirqs_off+0xd/0x10 > [ 13.270571] [] ? vprintk_emit+0x23c/0x570 > [ 13.277058] [] lock_acquire+0x93/0x120 > [ 13.283269] [] ? dmar_msi_mask+0x47/0x70 > [ 13.289677] [] _raw_spin_lock_irqsave+0x49/0x90 > [ 13.296748] [] ? dmar_msi_mask+0x47/0x70 > [ 13.303153] [] dmar_msi_mask+0x47/0x70 > [ 13.309354] [] irq_shutdown+0x53/0x60 > [ 13.315467] [] __free_irq+0x26d/0x280 > [ 13.321580] [] free_irq+0xf0/0x180 > [ 13.327395] [] free_dmar_iommu+0x271/0x2b0 > [ 13.333996] [] ? trace_hardirqs_on+0xd/0x10 > [ 13.340696] [] free_iommu+0x17/0x50 > [ 13.346597] [] init_dmars+0x691/0x77a > [ 13.352711] [] intel_iommu_init+0x351/0x438 > [ 13.359400] [] ? iommu_setup+0x27d/0x27d > [ 13.365806] [] pci_iommu_init+0x28/0x52 > [ 13.372114] [] do_one_initcall+0x122/0x180 > [ 13.378707] [] ? parse_args+0x1e8/0x320 > [ 13.385016] [] kernel_init_freeable+0x1e1/0x26c > [ 13.392100] [] ? do_early_param+0x88/0x88 > [ 13.398596] [] ? rest_init+0xd0/0xd0 > [ 13.404614] [] kernel_init+0xe/0x130 > [ 13.410626] [] ret_from_fork+0x7c/0xb0 > [ 13.416829] [] ? rest_init+0xd0/0xd0 > [ 13.422842] Code: ec 99 00 85 c0 8b 05 53 05 a5 00 41 0f 45 d8 85 c0 0f 84 ff 00 00 00 8b 05 99 f9 7e 01 49 89 fe 41 89 f7 85 c0 0f 84 03 01 00 00 <49> 8b 06 be 01 00 00 00 48 3d c0 0e 01 82 0f 44 de 41 83 ff 01 > [ 13.450191] RIP [] __lock_acquire+0x4d/0x12a0 > [ 13.458598] RSP > [ 13.462671] CR2: 0000000000000048 > [ 13.466551] ---[ end trace c5bd26a37c81d760 ]--- > > Signed-off-by: Jiang Liu > --- > drivers/iommu/intel-iommu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 0ec49da..426095e 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -1289,9 +1289,9 @@ void free_dmar_iommu(struct intel_iommu *iommu) > iommu_disable_translation(iommu); > > if (iommu->irq) { > - irq_set_handler_data(iommu->irq, NULL); > /* This will mask the irq */ > free_irq(iommu->irq, iommu); > + irq_set_handler_data(iommu->irq, NULL); > destroy_irq(iommu->irq); > } > > -- Thanks! Yijing