From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f197.google.com (mail-io0-f197.google.com [209.85.223.197]) by kanga.kvack.org (Postfix) with ESMTP id 733746B100C for ; Sat, 18 Aug 2018 18:05:04 -0400 (EDT) Received: by mail-io0-f197.google.com with SMTP id s14-v6so10168684ioc.0 for ; Sat, 18 Aug 2018 15:05:04 -0700 (PDT) Received: from mail-sor-f69.google.com (mail-sor-f69.google.com. [209.85.220.69]) by mx.google.com with SMTPS id l8-v6sor2820596itc.121.2018.08.18.15.05.02 for (Google Transport Security); Sat, 18 Aug 2018 15:05:02 -0700 (PDT) MIME-Version: 1.0 Date: Sat, 18 Aug 2018 15:05:02 -0700 Message-ID: <0000000000003427e80573bcde5c@google.com> Subject: KASAN: use-after-free Read in do_shrink_slab From: syzbot Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, aryabinin@virtuozzo.com, hannes@cmpxchg.org, jbacik@fb.com, ktkhai@virtuozzo.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mgorman@techsingularity.net, mhocko@suse.com, penguin-kernel@I-love.SAKURA.ne.jp, shakeelb@google.com, syzkaller-bugs@googlegroups.com, ying.huang@intel.com Hello, syzbot found the following crash on: HEAD commit: 1f7a4c73a739 Merge tag '9p-for-4.19-2' of git://github.com.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16c46d9a400000 kernel config: https://syzkaller.appspot.com/x/.config?x=68e80edb3c9718c5 dashboard link: https://syzkaller.appspot.com/bug?extid=d5f648a1bfe15678786b compiler: gcc (GCC) 8.0.1 20180413 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+d5f648a1bfe15678786b@syzkaller.appspotmail.com ================================================================== BUG: KASAN: use-after-free in do_shrink_slab+0xbd4/0xcb0 mm/vmscan.c:456 Read of size 8 at addr ffff8801ae513558 by task syz-executor6/20506 CPU: 0 PID: 20506 Comm: syz-executor6 Not tainted 4.18.0+ #195 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+0x1c9/0x2b4 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 do_shrink_slab+0xbd4/0xcb0 mm/vmscan.c:456 shrink_slab_memcg mm/vmscan.c:600 [inline] shrink_slab+0x7b7/0x990 mm/vmscan.c:673 shrink_node+0x429/0x16a0 mm/vmscan.c:2734 shrink_zones mm/vmscan.c:2963 [inline] do_try_to_free_pages+0x3e7/0x1290 mm/vmscan.c:3025 try_to_free_mem_cgroup_pages+0x49d/0xc90 mm/vmscan.c:3323 memory_high_write+0x283/0x310 mm/memcontrol.c:5399 cgroup_file_write+0x31f/0x840 kernel/cgroup/cgroup.c:3447 kernfs_fop_write+0x2ba/0x480 fs/kernfs/file.c:316 __vfs_write+0x117/0x9d0 fs/read_write.c:485 __kernel_write+0x10c/0x380 fs/read_write.c:506 write_pipe_buf+0x181/0x240 fs/splice.c:798 splice_from_pipe_feed fs/splice.c:503 [inline] __splice_from_pipe+0x38e/0x7c0 fs/splice.c:627 splice_from_pipe+0x1ea/0x340 fs/splice.c:662 default_file_splice_write+0x3c/0x90 fs/splice.c:810 do_splice_from fs/splice.c:852 [inline] direct_splice_actor+0x128/0x190 fs/splice.c:1019 splice_direct_to_actor+0x318/0x8f0 fs/splice.c:974 do_splice_direct+0x2d4/0x420 fs/splice.c:1062 do_sendfile+0x623/0xe20 fs/read_write.c:1440 __do_sys_sendfile64 fs/read_write.c:1501 [inline] __se_sys_sendfile64 fs/read_write.c:1487 [inline] __x64_sys_sendfile64+0x1fd/0x250 fs/read_write.c:1487 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457089 Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7151c7ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f7151c7b6d4 RCX: 0000000000457089 RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000004 RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d3cb0 R14: 00000000004c8769 R15: 0000000000000000 Allocated by task 19741: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 __do_kmalloc mm/slab.c:3718 [inline] __kmalloc+0x14e/0x760 mm/slab.c:3727 kmalloc_array include/linux/slab.h:635 [inline] kcalloc include/linux/slab.h:646 [inline] iter_file_splice_write+0x25d/0x1010 fs/splice.c:693 do_splice_from fs/splice.c:852 [inline] direct_splice_actor+0x128/0x190 fs/splice.c:1019 splice_direct_to_actor+0x318/0x8f0 fs/splice.c:974 do_splice_direct+0x2d4/0x420 fs/splice.c:1062 do_sendfile+0x623/0xe20 fs/read_write.c:1440 __do_sys_sendfile64 fs/read_write.c:1495 [inline] __se_sys_sendfile64 fs/read_write.c:1487 [inline] __x64_sys_sendfile64+0x15d/0x250 fs/read_write.c:1487 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 19741: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xd9/0x260 mm/slab.c:3813 iter_file_splice_write+0x78d/0x1010 fs/splice.c:777 do_splice_from fs/splice.c:852 [inline] direct_splice_actor+0x128/0x190 fs/splice.c:1019 splice_direct_to_actor+0x318/0x8f0 fs/splice.c:974 do_splice_direct+0x2d4/0x420 fs/splice.c:1062 do_sendfile+0x623/0xe20 fs/read_write.c:1440 __do_sys_sendfile64 fs/read_write.c:1495 [inline] __se_sys_sendfile64 fs/read_write.c:1487 [inline] __x64_sys_sendfile64+0x15d/0x250 fs/read_write.c:1487 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 ffff8801ae513500 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 88 bytes inside of 256-byte region [ffff8801ae513500, ffff8801ae513600) The buggy address belongs to the page: page:ffffea0006b944c0 count:1 mapcount:0 mapping:ffff8801dac007c0 index:0xffff8801ae513b40 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea000701dd48 ffff8801dac01638 ffff8801dac007c0 raw: ffff8801ae513b40 ffff8801ae513000 000000010000000a 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801ae513400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801ae513480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff8801ae513500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801ae513580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801ae513600: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ================================================================== --- This bug is generated by a bot. 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