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1.0 X-Received: by 2002:a5d:8b52:: with SMTP id c18mr46942971iot.89.1563515287043; Thu, 18 Jul 2019 22:48:07 -0700 (PDT) Date: Thu, 18 Jul 2019 22:48:07 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000490679058e0245ee@google.com> Subject: KASAN: use-after-free Read in finish_task_switch (2) From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 22051d9c Merge tag 'platform-drivers-x86-v5.3-2' of git://.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=12dab5a4600000 kernel config: https://syzkaller.appspot.com/x/.config?x=135cb826ac59d7fc dashboard link: https://syzkaller.appspot.com/bug?extid=7f067c796eee2acbc57a compiler: clang version 9.0.0 (/home/glider/llvm/clang 80fee25776c2fb61e74c1ecb1a523375c2500b69) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12c1898fa00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+7f067c796eee2acbc57a@syzkaller.appspotmail.com IPv6: ADDRCONF(NETDEV_CHANGE): hsr0: link becomes ready 8021q: adding VLAN 0 to HW filter on device batadv0 ================================================================== BUG: KASAN: use-after-free in atomic_read /./include/asm-generic/atomic-instrumented.h:26 [inline] BUG: KASAN: use-after-free in membarrier_mm_sync_core_before_usermode /./include/linux/sched/mm.h:365 [inline] BUG: KASAN: use-after-free in finish_task_switch+0x331/0x550 /kernel/sched/core.c:3122 Read of size 4 at addr ffff88808e6c18f8 by task syz-executor.0/8218 CPU: 0 PID: 8218 Comm: syz-executor.0 Not tainted 5.2.0+ #34 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+0x1d8/0x2f8 /lib/dump_stack.c:113 print_address_description+0x75/0x5b0 /mm/kasan/report.c:351 __kasan_report+0x14b/0x1c0 /mm/kasan/report.c:482 kasan_report+0x26/0x50 /mm/kasan/common.c:612 check_memory_region_inline /mm/kasan/generic.c:182 [inline] check_memory_region+0x2cf/0x2e0 /mm/kasan/generic.c:192 __kasan_check_read+0x11/0x20 /mm/kasan/common.c:92 atomic_read /./include/asm-generic/atomic-instrumented.h:26 [inline] membarrier_mm_sync_core_before_usermode /./include/linux/sched/mm.h:365 [inline] finish_task_switch+0x331/0x550 /kernel/sched/core.c:3122 context_switch /kernel/sched/core.c:3257 [inline] __schedule+0x8be/0xcd0 /kernel/sched/core.c:3880 schedule+0x131/0x1e0 /kernel/sched/core.c:3944 freezable_schedule /./include/linux/freezer.h:172 [inline] do_nanosleep+0x295/0x7d0 /kernel/time/hrtimer.c:1679 hrtimer_nanosleep+0x3c2/0x5d0 /kernel/time/hrtimer.c:1733 __do_sys_nanosleep /kernel/time/hrtimer.c:1767 [inline] __se_sys_nanosleep /kernel/time/hrtimer.c:1754 [inline] __x64_sys_nanosleep+0x1ef/0x230 /kernel/time/hrtimer.c:1754 do_syscall_64+0xfe/0x140 /arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457cc0 Code: c0 5b 5d c3 66 0f 1f 44 00 00 8b 04 24 48 83 c4 18 5b 5d c3 66 0f 1f 44 00 00 83 3d 91 ea 61 00 00 75 14 b8 23 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 24 d3 fb ff c3 48 83 ec 08 e8 ea 46 00 00 RSP: 002b:00007ffc89355738 EFLAGS: 00000246 ORIG_RAX: 0000000000000023 RAX: ffffffffffffffda RBX: 000000000000ea43 RCX: 0000000000457cc0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffc89355740 RBP: 000000000000000b R08: 0000000000000001 R09: 00005555559bf940 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000007 R13: 00007ffc89355790 R14: 000000000000e9c0 R15: 00007ffc893557a0 Allocated by task 8218: save_stack /mm/kasan/common.c:69 [inline] set_track /mm/kasan/common.c:77 [inline] __kasan_kmalloc+0x11c/0x1b0 /mm/kasan/common.c:487 kasan_slab_alloc+0xf/0x20 /mm/kasan/common.c:495 slab_post_alloc_hook /mm/slab.h:520 [inline] slab_alloc /mm/slab.c:3319 [inline] kmem_cache_alloc+0x1f5/0x2e0 /mm/slab.c:3483 dup_mm+0x29/0x340 /kernel/fork.c:1337 copy_mm /kernel/fork.c:1402 [inline] copy_process+0x25ef/0x5bc0 /kernel/fork.c:2017 _do_fork+0x179/0x630 /kernel/fork.c:2369 __do_sys_clone /kernel/fork.c:2524 [inline] __se_sys_clone /kernel/fork.c:2505 [inline] __x64_sys_clone+0x247/0x2b0 /kernel/fork.c:2505 do_syscall_64+0xfe/0x140 /arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8244: save_stack /mm/kasan/common.c:69 [inline] set_track /mm/kasan/common.c:77 [inline] __kasan_slab_free+0x12a/0x1e0 /mm/kasan/common.c:449 kasan_slab_free+0xe/0x10 /mm/kasan/common.c:457 __cache_free /mm/slab.c:3425 [inline] kmem_cache_free+0x81/0xf0 /mm/slab.c:3693 __mmdrop+0x2c4/0x3b0 /kernel/fork.c:683 mmdrop /./include/linux/sched/mm.h:49 [inline] __mmput+0x373/0x3a0 /kernel/fork.c:1074 mmput+0x5d/0x70 /kernel/fork.c:1085 exit_mm+0x585/0x640 /kernel/exit.c:547 do_exit+0x5d0/0x2310 /kernel/exit.c:864 do_group_exit+0x15c/0x2b0 /kernel/exit.c:981 get_signal+0x51c/0x1dd0 /kernel/signal.c:2728 do_signal+0x7b/0x720 /arch/x86/kernel/signal.c:815 exit_to_usermode_loop /arch/x86/entry/common.c:159 [inline] prepare_exit_to_usermode+0x303/0x580 /arch/x86/entry/common.c:194 syscall_return_slowpath+0x113/0x4a0 /arch/x86/entry/common.c:274 do_syscall_64+0x126/0x140 /arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88808e6c1400 which belongs to the cache mm_struct(17:syz0) of size 1496 The buggy address is located 1272 bytes inside of 1496-byte region [ffff88808e6c1400, ffff88808e6c19d8) The buggy address belongs to the page: page:ffffea000239b000 refcount:1 mapcount:0 mapping:ffff8880867de8c0 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0002331108 ffff8880a380ff48 ffff8880867de8c0 raw: 0000000000000000 ffff88808e6c0080 0000000100000004 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808e6c1780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808e6c1800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88808e6c1880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808e6c1900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808e6c1980: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc ================================================================== --- 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#status for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches