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=-5.7 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 262B6C282DC for ; Fri, 19 Apr 2019 03:45:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E35CD21736 for ; Fri, 19 Apr 2019 03:45:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727259AbfDSDpG (ORCPT ); Thu, 18 Apr 2019 23:45:06 -0400 Received: from mail-it1-f198.google.com ([209.85.166.198]:39359 "EHLO mail-it1-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP 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MIME-Version: 1.0 X-Received: by 2002:a5d:899a:: with SMTP id m26mr1424176iol.268.1555645505345; Thu, 18 Apr 2019 20:45:05 -0700 (PDT) Date: Thu, 18 Apr 2019 20:45:05 -0700 In-Reply-To: <0000000000004a6d7c057e77e97e@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000be25710586d9f15a@google.com> Subject: Re: KASAN: use-after-free Read in refcount_sub_and_test_checked (2) From: syzbot To: -O-request@vger.kernel.org, acme@kernel.org, alexander.shishkin@linux.intel.com, andrew.hendry@gmail.com, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, davem@davemloft.net, dvlasenk@redhat.com, gregkh@linuxfoundation.org, jolsa@redhat.com, kafai@fb.com, linux-kernel@vger.kernel.org, linux-x25@vger.kernel.org, mingo@redhat.com, ms@dev.tdt.de, namhyung@kernel.org, netdev@vger.kernel.org, peterz@infradead.org, songliubraving@fb.com, syzkaller-bugs@googlegroups.com, yhs@fb.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: 6d906f99 Merge tag 'arm64-fixes' of git://git.kernel.org/p.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=129b4003200000 kernel config: https://syzkaller.appspot.com/x/.config?x=856fc6d0fbbeede9 dashboard link: https://syzkaller.appspot.com/bug?extid=b0775615fa4c4479b691 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15df396b200000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+b0775615fa4c4479b691@syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] BUG: KASAN: use-after-free in refcount_sub_and_test_checked+0x87/0x200 lib/refcount.c:182 Read of size 4 at addr ffff8880a8d5e060 by task syz-executor.0/31157 CPU: 0 PID: 31157 Comm: syz-executor.0 Not tainted 5.1.0-rc5+ #74 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+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x123/0x190 mm/kasan/generic.c:191 kasan_check_read+0x11/0x20 mm/kasan/common.c:102 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] refcount_sub_and_test_checked+0x87/0x200 lib/refcount.c:182 refcount_dec_and_test_checked+0x1b/0x20 lib/refcount.c:220 put_task_struct include/linux/sched/task.h:97 [inline] _free_event+0x3d7/0x13b0 kernel/events/core.c:4460 free_event+0x5f/0xd0 kernel/events/core.c:4481 perf_event_release_kernel+0x5b2/0xbe0 kernel/events/core.c:4642 perf_release+0x37/0x50 kernel/events/core.c:4656 __fput+0x2e5/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4129e1 Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 e4 1a 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007ffc793703e0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00000000004129e1 RDX: 0000000000000000 RSI: 0000000000000081 RDI: 0000000000000003 RBP: 0000000000741220 R08: 0000000000741218 R09: 000000000002c9b0 R10: 00007ffc793704a0 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000003 R15: 000000000073bfac Allocated by task 31160: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_kmalloc mm/kasan/common.c:497 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:505 slab_post_alloc_hook mm/slab.h:437 [inline] slab_alloc_node mm/slab.c:3337 [inline] kmem_cache_alloc_node+0x131/0x710 mm/slab.c:3647 alloc_task_struct_node kernel/fork.c:157 [inline] dup_task_struct kernel/fork.c:844 [inline] copy_process.part.0+0x1d08/0x7980 kernel/fork.c:1752 copy_process kernel/fork.c:1709 [inline] _do_fork+0x257/0xfd0 kernel/fork.c:2226 __do_sys_clone kernel/fork.c:2333 [inline] __se_sys_clone kernel/fork.c:2327 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2327 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 31160: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467 __cache_free mm/slab.c:3500 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3766 free_task_struct kernel/fork.c:162 [inline] free_task+0xdd/0x120 kernel/fork.c:457 copy_process.part.0+0x1a3a/0x7980 kernel/fork.c:2158 copy_process kernel/fork.c:1709 [inline] _do_fork+0x257/0xfd0 kernel/fork.c:2226 __do_sys_clone kernel/fork.c:2333 [inline] __se_sys_clone kernel/fork.c:2327 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2327 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880a8d5e040 which belongs to the cache task_struct(44:syz0) of size 6080 The buggy address is located 32 bytes inside of 6080-byte region [ffff8880a8d5e040, ffff8880a8d5f800) The buggy address belongs to the page: page:ffffea0002a35780 count:1 mapcount:0 mapping:ffff88808b2adcc0 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0002301808 ffffea0002171f08 ffff88808b2adcc0 raw: 0000000000000000 ffff8880a8d5e040 0000000100000001 ffff888085710580 page dumped because: kasan: bad access detected page->mem_cgroup:ffff888085710580 Memory state around the buggy address: ffff8880a8d5df00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880a8d5df80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8880a8d5e000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8880a8d5e080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a8d5e100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================