[ +John ] On 05/26/2018 10:54 AM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 3fb48d881dbe Merge branch 'bpf-fib-mtu-check' > git tree: bpf-next > console output: https://syzkaller.appspot.com/x/log.txt?x=15fc1977800000 > kernel config: https://syzkaller.appspot.com/x/.config?x=b632d8e2c2ab2c1 > dashboard link: https://syzkaller.appspot.com/bug?extid=fce8f2462c403d02af98 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=1310c857800000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17de7177800000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+fce8f2462c403d02a...@syzkaller.appspotmail.com
Should be fixed by: https://patchwork.ozlabs.org/patch/920695/ > ================================================================== > BUG: KASAN: use-after-free in hlist_del_rcu include/linux/rculist.h:427 > [inline] > BUG: KASAN: use-after-free in bpf_tcp_close+0xd7f/0xf80 > kernel/bpf/sockmap.c:271 > Read of size 8 at addr ffff8801c884cf90 by task syz-executor330/11778 > > CPU: 1 PID: 11778 Comm: syz-executor330 Not tainted 4.17.0-rc4+ #18 > 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+0x1b9/0x294 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+0x242/0x2fe mm/kasan/report.c:412 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 > hlist_del_rcu include/linux/rculist.h:427 [inline] > bpf_tcp_close+0xd7f/0xf80 kernel/bpf/sockmap.c:271 > inet_release+0x104/0x1f0 net/ipv4/af_inet.c:427 > inet6_release+0x50/0x70 net/ipv6/af_inet6.c:459 > sock_release+0x96/0x1b0 net/socket.c:594 > sock_close+0x16/0x20 net/socket.c:1149 > __fput+0x34d/0x890 fs/file_table.c:209 > ____fput+0x15/0x20 fs/file_table.c:243 > task_work_run+0x1e4/0x290 kernel/task_work.c:113 > exit_task_work include/linux/task_work.h:22 [inline] > do_exit+0x1aee/0x2730 kernel/exit.c:865 > do_group_exit+0x16f/0x430 kernel/exit.c:968 > get_signal+0x886/0x1960 kernel/signal.c:2469 > do_signal+0x98/0x2040 arch/x86/kernel/signal.c:810 > exit_to_usermode_loop+0x28a/0x310 arch/x86/entry/common.c:162 > prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] > syscall_return_slowpath arch/x86/entry/common.c:265 [inline] > do_syscall_64+0x6ac/0x800 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x445ed9 > RSP: 002b:00007f0078c0adb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca > RAX: fffffffffffffe00 RBX: 00000000006dbc24 RCX: 0000000000445ed9 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000006dbc24 > RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: 00007ffcd147dbef R14: 00007f0078c0b9c0 R15: 0000000000000007 > > Allocated by task 11787: > 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_node mm/slab.c:3682 [inline] > __kmalloc_node+0x47/0x70 mm/slab.c:3689 > kmalloc_node include/linux/slab.h:554 [inline] > alloc_sock_hash_elem kernel/bpf/sockmap.c:2114 [inline] > sock_hash_ctx_update_elem.isra.23+0xa57/0x1560 kernel/bpf/sockmap.c:2245 > sock_hash_update_elem+0x14f/0x2d0 kernel/bpf/sockmap.c:2303 > map_update_elem+0x5c4/0xc90 kernel/bpf/syscall.c:760 > __do_sys_bpf kernel/bpf/syscall.c:2134 [inline] > __se_sys_bpf kernel/bpf/syscall.c:2105 [inline] > __x64_sys_bpf+0x32a/0x4f0 kernel/bpf/syscall.c:2105 > do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 8998: > 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 > sock_hash_free+0x24e/0x6e0 kernel/bpf/sockmap.c:2093 > bpf_map_free_deferred+0xba/0xf0 kernel/bpf/syscall.c:259 > process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145 > worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279 > kthread+0x345/0x410 kernel/kthread.c:238 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 > > The buggy address belongs to the object at ffff8801c884cf80 > which belongs to the cache kmalloc-64 of size 64 > The buggy address is located 16 bytes inside of > 64-byte region [ffff8801c884cf80, ffff8801c884cfc0) > The buggy address belongs to the page: > page:ffffea0007221300 count:1 mapcount:0 mapping:ffff8801c884c000 index:0x0 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffff8801c884c000 0000000000000000 0000000100000020 > raw: ffffea00072e08e0 ffffea0006e99660 ffff8801da800340 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801c884ce80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff8801c884cf00: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc >> ffff8801c884cf80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ^ > ffff8801c884d000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb > ffff8801c884d080: 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 syzkal...@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