From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4D6A3C0044C for ; Mon, 29 Oct 2018 11:51:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CE72E2082B for ; Mon, 29 Oct 2018 11:51:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="BJuVmpV7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE72E2082B Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728929AbeJ2Uj5 (ORCPT ); Mon, 29 Oct 2018 16:39:57 -0400 Received: from mail-io1-f65.google.com ([209.85.166.65]:36901 "EHLO mail-io1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728033AbeJ2Uj4 (ORCPT ); Mon, 29 Oct 2018 16:39:56 -0400 Received: by mail-io1-f65.google.com with SMTP id k17-v6so4742342ioc.4 for ; Mon, 29 Oct 2018 04:51:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=0mKsBXhYcsDLul10YwfxiiDczdSpYJ+wzShQ2UONIcU=; b=BJuVmpV7Z4iZEis+1ha60dtC0GFPqWg9O10AdYgeBTTvx1LfcHw8GuHA8IrHBQ+Bdu f4vC3/CPjeLfQ3RbNx4AVPL6M0FsW/8umgrZlehSTl641E75osc0IjeifYFzreGZQ9xt 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AJdET5ewFpFDJr+jJNnFL/FpwFEzQDUZEraZUyGp+0qWDmLkqHVwM8j0dDnG7UV9PvMijYqZbo214FcTW3tzBARMhes= X-Received: by 2002:a6b:9383:: with SMTP id v125-v6mr6840407iod.282.1540813894997; Mon, 29 Oct 2018 04:51:34 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a02:1003:0:0:0:0:0 with HTTP; Mon, 29 Oct 2018 04:51:14 -0700 (PDT) In-Reply-To: <00000000000053fea105791276d8@google.com> References: <00000000000053fea105791276d8@google.com> From: Dmitry Vyukov Date: Mon, 29 Oct 2018 12:51:14 +0100 Message-ID: Subject: Re: KASAN: use-after-free Read in drm_gem_object_release To: syzbot , Gustavo Padovan , maarten.lankhorst@linux.intel.com, sean@poorly.run, David Airlie , DRI Cc: LKML , syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 25, 2018 at 9:18 PM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: bd6bf7c10484 Merge tag 'pci-v4.20-changes' of git://git.ke.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1448a683400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=2dd8629d56664133 > dashboard link: https://syzkaller.appspot.com/bug?extid=e73f2fb5ed5a5df36d33 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11331de5400000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1334e64d400000 +drm maintainers > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+e73f2fb5ed5a5df36d33@syzkaller.appspotmail.com > > drm_mode_create_dumb+0x28d/0x310 drivers/gpu/drm/drm_dumb_buffers.c:92 > drm_mode_create_dumb_ioctl+0x25/0x30 drivers/gpu/drm/drm_dumb_buffers.c:98 > drm_ioctl_kernel+0x245/0x2f0 drivers/gpu/drm/drm_ioctl.c:751 > drm_ioctl+0x57a/0xb20 drivers/gpu/drm/drm_ioctl.c:847 > ================================================================== > BUG: KASAN: use-after-free in drm_gem_object_release+0xf1/0x110 > drivers/gpu/drm/drm_gem.c:813 > Read of size 8 at addr ffff8801d83d3410 by task syz-executor977/6742 > > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:501 [inline] > do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 > __do_sys_ioctl fs/ioctl.c:709 [inline] > __se_sys_ioctl fs/ioctl.c:707 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x445989 > Code: e8 4c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 > 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff > 0f 83 6b c8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007ffcf076f4e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007ffcf076f500 RCX: 0000000000445989 > RDX: 0000000020000000 RSI: ffffffffffffffb2 RDI: 0000000000000003 > RBP: 0000000000000004 R08: 0000000000000001 R09: 0000000000000100 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: ffffffffffffffff R14: 0000000000000000 R15: 0000000000000000 > CPU: 0 PID: 6742 Comm: syz-executor977 Not tainted 4.19.0+ #80 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x244/0x39d lib/dump_stack.c:113 > print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256 > kasan_report_error mm/kasan/report.c:354 [inline] > kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 > drm_gem_object_release+0xf1/0x110 drivers/gpu/drm/drm_gem.c:813 > __vgem_gem_destroy drivers/gpu/drm/vgem/vgem_drv.c:175 [inline] > vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:199 [inline] > vgem_gem_dumb_create+0x1f8/0x260 drivers/gpu/drm/vgem/vgem_drv.c:214 > drm_mode_create_dumb+0x28d/0x310 drivers/gpu/drm/drm_dumb_buffers.c:92 > drm_mode_create_dumb_ioctl+0x25/0x30 drivers/gpu/drm/drm_dumb_buffers.c:98 > drm_ioctl_kernel+0x245/0x2f0 drivers/gpu/drm/drm_ioctl.c:751 > drm_ioctl+0x57a/0xb20 drivers/gpu/drm/drm_ioctl.c:847 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:501 [inline] > do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 > __do_sys_ioctl fs/ioctl.c:709 [inline] > __se_sys_ioctl fs/ioctl.c:707 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x445989 > Code: e8 4c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 > 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff > 0f 83 6b c8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007ffcf076f4e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007ffcf076f500 RCX: 0000000000445989 > RDX: 0000000020000000 RSI: ffffffffffffffb2 RDI: 0000000000000003 > RBP: 0000000000000004 R08: 0000000000000001 R09: 0000000000000100 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: ffffffffffffffff R14: 0000000000000000 R15: 0000000000000000 > > Allocated by task 6742: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 > kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620 > kmalloc include/linux/slab.h:513 [inline] > kzalloc include/linux/slab.h:707 [inline] > __vgem_gem_create+0x4c/0x100 drivers/gpu/drm/vgem/vgem_drv.c:158 > vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:187 [inline] > vgem_gem_dumb_create+0xce/0x260 drivers/gpu/drm/vgem/vgem_drv.c:214 > drm_mode_create_dumb+0x28d/0x310 drivers/gpu/drm/drm_dumb_buffers.c:92 > drm_mode_create_dumb_ioctl+0x25/0x30 drivers/gpu/drm/drm_dumb_buffers.c:98 > drm_ioctl_kernel+0x245/0x2f0 drivers/gpu/drm/drm_ioctl.c:751 > drm_ioctl+0x57a/0xb20 drivers/gpu/drm/drm_ioctl.c:847 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:501 [inline] > do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 > __do_sys_ioctl fs/ioctl.c:709 [inline] > __se_sys_ioctl fs/ioctl.c:707 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 6742: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > __cache_free mm/slab.c:3498 [inline] > kfree+0xcf/0x230 mm/slab.c:3813 > vgem_gem_free_object+0xb6/0xe0 drivers/gpu/drm/vgem/vgem_drv.c:61 > drm_gem_object_free+0xf1/0x2b0 drivers/gpu/drm/drm_gem.c:839 > kref_put include/linux/kref.h:70 [inline] > drm_gem_object_put_unlocked+0x14c/0x180 drivers/gpu/drm/drm_gem.c:895 > vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:192 [inline] > vgem_gem_dumb_create+0x120/0x260 drivers/gpu/drm/vgem/vgem_drv.c:214 > drm_mode_create_dumb+0x28d/0x310 drivers/gpu/drm/drm_dumb_buffers.c:92 > drm_mode_create_dumb_ioctl+0x25/0x30 drivers/gpu/drm/drm_dumb_buffers.c:98 > drm_ioctl_kernel+0x245/0x2f0 drivers/gpu/drm/drm_ioctl.c:751 > drm_ioctl+0x57a/0xb20 drivers/gpu/drm/drm_ioctl.c:847 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:501 [inline] > do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 > __do_sys_ioctl fs/ioctl.c:709 [inline] > __se_sys_ioctl fs/ioctl.c:707 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff8801d83d3300 > which belongs to the cache kmalloc-512 of size 512 > The buggy address is located 272 bytes inside of > 512-byte region [ffff8801d83d3300, ffff8801d83d3500) > The buggy address belongs to the page: > page:ffffea000760f4c0 count:1 mapcount:0 mapping:ffff8801da800940 index:0x0 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffffea0007473948 ffffea0007471dc8 ffff8801da800940 > raw: 0000000000000000 ffff8801d83d3080 0000000100000006 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801d83d3300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801d83d3380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> >> ffff8801d83d3400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ^ > ffff8801d83d3480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801d83d3500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ================================================================== > ================================================================== > CPU: 0 PID: 6778 Comm: syz-executor977 Tainted: G B 4.19.0+ > #80 > BUG: KASAN: double-free or invalid-free in __vgem_gem_destroy > drivers/gpu/drm/vgem/vgem_drv.c:176 [inline] > BUG: KASAN: double-free or invalid-free in vgem_gem_create > drivers/gpu/drm/vgem/vgem_drv.c:199 [inline] > BUG: KASAN: double-free or invalid-free in vgem_gem_dumb_create+0x203/0x260 > drivers/gpu/drm/vgem/vgem_drv.c:214 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x244/0x39d lib/dump_stack.c:113 > fail_dump lib/fault-inject.c:51 [inline] > should_fail.cold.4+0xa/0x17 lib/fault-inject.c:149 > __should_failslab+0x124/0x180 mm/failslab.c:32 > should_failslab+0x9/0x14 mm/slab_common.c:1557 > slab_pre_alloc_hook mm/slab.h:423 [inline] > slab_alloc mm/slab.c:3378 [inline] > kmem_cache_alloc_trace+0x2d7/0x750 mm/slab.c:3618 > kmalloc include/linux/slab.h:513 [inline] > drm_vma_node_allow+0x5f/0x290 drivers/gpu/drm/drm_vma_manager.c:277 > drm_gem_handle_create_tail+0x233/0x440 drivers/gpu/drm/drm_gem.c:409 > drm_gem_handle_create+0x52/0x60 drivers/gpu/drm/drm_gem.c:452 > vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:191 [inline] > vgem_gem_dumb_create+0x115/0x260 drivers/gpu/drm/vgem/vgem_drv.c:214 > drm_mode_create_dumb+0x28d/0x310 drivers/gpu/drm/drm_dumb_buffers.c:92 > drm_mode_create_dumb_ioctl+0x25/0x30 drivers/gpu/drm/drm_dumb_buffers.c:98 > drm_ioctl_kernel+0x245/0x2f0 drivers/gpu/drm/drm_ioctl.c:751 > drm_ioctl+0x57a/0xb20 drivers/gpu/drm/drm_ioctl.c:847 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:501 [inline] > do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 > __do_sys_ioctl fs/ioctl.c:709 [inline] > __se_sys_ioctl fs/ioctl.c:707 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x445989 > Code: e8 4c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 > 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff > 0f 83 6b c8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007ffcf076f4e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007ffcf076f500 RCX: 0000000000445989 > RDX: 0000000020000000 RSI: ffffffffffffffb2 RDI: 0000000000000003 > RBP: 0000000000000004 R08: 0000000000000001 R09: 0000000000000100 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: ffffffffffffffff R14: 0000000000000000 R15: 0000000000000000 > CPU: 1 PID: 6767 Comm: syz-executor977 Tainted: G B 4.19.0+ > #80 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x244/0x39d lib/dump_stack.c:113 > print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256 > kasan_report_invalid_free+0x64/0xa0 mm/kasan/report.c:336 > __kasan_slab_free+0x13a/0x150 mm/kasan/kasan.c:501 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > __cache_free mm/slab.c:3498 [inline] > kfree+0xcf/0x230 mm/slab.c:3813 > __vgem_gem_destroy drivers/gpu/drm/vgem/vgem_drv.c:176 [inline] > vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:199 [inline] > vgem_gem_dumb_create+0x203/0x260 drivers/gpu/drm/vgem/vgem_drv.c:214 > drm_mode_create_dumb+0x28d/0x310 drivers/gpu/drm/drm_dumb_buffers.c:92 > drm_mode_create_dumb_ioctl+0x25/0x30 drivers/gpu/drm/drm_dumb_buffers.c:98 > drm_ioctl_kernel+0x245/0x2f0 drivers/gpu/drm/drm_ioctl.c:751 > drm_ioctl+0x57a/0xb20 drivers/gpu/drm/drm_ioctl.c:847 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:501 [inline] > do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 > __do_sys_ioctl fs/ioctl.c:709 [inline] > __se_sys_ioctl fs/ioctl.c:707 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x445989 > Code: e8 4c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 > 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff > 0f 83 6b c8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007ffcf076f4e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007ffcf076f500 RCX: 0000000000445989 > RDX: 0000000020000000 RSI: ffffffffffffffb2 RDI: 0000000000000003 > RBP: 0000000000000004 R08: 0000000000000001 R09: 0000000000000100 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: ffffffffffffffff R14: 0000000000000000 R15: 0000000000000000 > > Allocated by task 6767: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 > kmem_cache_alloc_trace+0x152/0x750 mm/slab.c:3620 > kmalloc include/linux/slab.h:513 [inline] > kzalloc include/linux/slab.h:707 [inline] > __vgem_gem_create+0x4c/0x100 drivers/gpu/drm/vgem/vgem_drv.c:158 > vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:187 [inline] > vgem_gem_dumb_create+0xce/0x260 drivers/gpu/drm/vgem/vgem_drv.c:214 > drm_mode_create_dumb+0x28d/0x310 drivers/gpu/drm/drm_dumb_buffers.c:92 > drm_mode_create_dumb_ioctl+0x25/0x30 drivers/gpu/drm/drm_dumb_buffers.c:98 > drm_ioctl_kernel+0x245/0x2f0 drivers/gpu/drm/drm_ioctl.c:751 > drm_ioctl+0x57a/0xb20 drivers/gpu/drm/drm_ioctl.c:847 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:501 [inline] > do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 > __do_sys_ioctl fs/ioctl.c:709 [inline] > __se_sys_ioctl fs/ioctl.c:707 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 6767: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > __cache_free mm/slab.c:3498 [inline] > kfree+0xcf/0x230 mm/slab.c:3813 > vgem_gem_free_object+0xb6/0xe0 drivers/gpu/drm/vgem/vgem_drv.c:61 > drm_gem_object_free+0xf1/0x2b0 drivers/gpu/drm/drm_gem.c:839 > kref_put include/linux/kref.h:70 [inline] > drm_gem_object_put_unlocked+0x14c/0x180 drivers/gpu/drm/drm_gem.c:895 > vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:192 [inline] > vgem_gem_dumb_create+0x120/0x260 drivers/gpu/drm/vgem/vgem_drv.c:214 > drm_mode_create_dumb+0x28d/0x310 drivers/gpu/drm/drm_dumb_buffers.c:92 > drm_mode_create_dumb_ioctl+0x25/0x30 drivers/gpu/drm/drm_dumb_buffers.c:98 > drm_ioctl_kernel+0x245/0x2f0 drivers/gpu/drm/drm_ioctl.c:751 > drm_ioctl+0x57a/0xb20 drivers/gpu/drm/drm_ioctl.c:847 > vfs_ioctl fs/ioctl.c:46 [inline] > file_ioctl fs/ioctl.c:501 [inline] > do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 > __do_sys_ioctl fs/ioctl.c:709 [inline] > __se_sys_ioctl fs/ioctl.c:707 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff8801d4974080 > which belongs to the cache kmalloc-512 of size 512 > The buggy address is located 0 bytes inside of > 512-byte region [ffff8801d4974080, ffff8801d4974280) > The buggy address belongs to the page: > page:ffffea0007525d00 count:1 mapcount:0 mapping:ffff8801da800940 index:0x0 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffffea0007558e48 ffffea00071d0508 ffff8801da800940 > raw: 0000000000000000 ffff8801d4974080 0000000100000006 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801d4973f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8801d4974000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> >> ffff8801d4974080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ^ > ffff8801d4974100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801d4974180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > ================================================================== > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with > syzbot. > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches > > -- > You received this message because you are subscribed to the Google Groups > "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/syzkaller-bugs/00000000000053fea105791276d8%40google.com. > For more options, visit https://groups.google.com/d/optout.