[ +John ] On 05/27/2018 10:06 PM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: ff4fb475cea8 Merge branch 'btf-uapi-cleanups' > git tree: bpf-next > console output: https://syzkaller.appspot.com/x/log.txt?x=12b3d577800000 > kernel config: https://syzkaller.appspot.com/x/.config?x=b632d8e2c2ab2c1 > dashboard link: https://syzkaller.appspot.com/bug?extid=31025a5f3f7650081204 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=109a2f37800000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=171a727b800000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+31025a5f3f7650081...@syzkaller.appspotmail.com
Should be fixed by: https://patchwork.ozlabs.org/patch/920695/ > ================================================================== > BUG: KASAN: use-after-free in cmpxchg_size > include/asm-generic/atomic-instrumented.h:355 [inline] > BUG: KASAN: use-after-free in bpf_tcp_close+0x6f5/0xf80 > kernel/bpf/sockmap.c:265 > Write of size 8 at addr ffff8801ca277680 by task syz-executor749/9723 > > CPU: 0 PID: 9723 Comm: syz-executor749 Not tainted 4.17.0-rc4+ #19 > 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 > check_memory_region_inline mm/kasan/kasan.c:260 [inline] > check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 > kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278 > cmpxchg_size include/asm-generic/atomic-instrumented.h:355 [inline] > bpf_tcp_close+0x6f5/0xf80 kernel/bpf/sockmap.c:265 > 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 > __do_sys_exit_group kernel/exit.c:979 [inline] > __se_sys_exit_group kernel/exit.c:977 [inline] > __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:977 > do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x440a59 > RSP: 002b:00007ffdadf92488 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7 > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440a59 > RDX: 0000000000440a59 RSI: 0000000000000020 RDI: 0000000000000000 > RBP: 0000000000000000 R08: 00000000004002c8 R09: 0000000000401ea0 > R10: 00000000004002c8 R11: 0000000000000206 R12: 000000000001b5ac > R13: 0000000000401ea0 R14: 0000000000000000 R15: 0000000000000000 > > Allocated by task 9723: > 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] > bpf_map_area_alloc+0x3f/0x90 kernel/bpf/syscall.c:144 > sock_map_alloc+0x376/0x410 kernel/bpf/sockmap.c:1555 > find_and_alloc_map kernel/bpf/syscall.c:126 [inline] > map_create+0x393/0x1010 kernel/bpf/syscall.c:448 > __do_sys_bpf kernel/bpf/syscall.c:2128 [inline] > __se_sys_bpf kernel/bpf/syscall.c:2105 [inline] > __x64_sys_bpf+0x300/0x4f0 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 4521: > 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 > kvfree+0x61/0x70 mm/util.c:440 > bpf_map_area_free+0x15/0x20 kernel/bpf/syscall.c:155 > sock_map_remove_complete kernel/bpf/sockmap.c:1443 [inline] > sock_map_free+0x408/0x540 kernel/bpf/sockmap.c:1619 > 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 ffff8801ca277680 > which belongs to the cache kmalloc-1024 of size 1024 > The buggy address is located 0 bytes inside of > 1024-byte region [ffff8801ca277680, ffff8801ca277a80) > The buggy address belongs to the page: > page:ffffea0007289d80 count:1 mapcount:0 mapping:ffff8801ca276000 index:0x0 > compound_mapcount: 0 > flags: 0x2fffc0000008100(slab|head) > raw: 02fffc0000008100 ffff8801ca276000 0000000000000000 0000000100000007 > raw: ffffea0006d12b20 ffffea000763bba0 ffff8801da800ac0 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801ca277580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8801ca277600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff8801ca277680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8801ca277700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801ca277780: 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
