On 2018/09/08 0:29, syzbot wrote: > syzbot has found a reproducer for the following crash on: > > HEAD commit: 28619527b8a7 Merge git://git.kernel.org/pub/scm/linux/kern.. > git tree: bpf > console output: https://syzkaller.appspot.com/x/log.txt?x=124e64d1400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=62e9b447c16085cf > dashboard link: https://syzkaller.appspot.com/bug?extid=a3c9d2673837ccc0f22b > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=179f9cd1400000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11b3e8be400000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+a3c9d2673837ccc0f22b@xxxxxxxxxxxxxxxxxxxxxxxxx > > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x440479 > usercopy: Kernel memory overwrite attempt detected to spans multiple pages (offset 0, size 64)! Kees, is this because check_page_span() is failing to allow on-stack variable u8 opcodes[OPCODE_BUFSIZE]; which by chance crossed PAGE_SIZE boundary?
