On 2017/12/18 22:40, syzbot wrote: > Hello, > > syzkaller hit the following crash on 6084b576dca2e898f5c101baef151f7bfdbb606d > git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master > compiler: gcc (GCC) 7.1.1 20170620 > .config is attached > Raw console output is attached. > > Unfortunately, I don't have any reproducer for this bug yet. > > This BUG is reporting [ 26.089789] usercopy: kernel memory overwrite attempt detected to 0000000022a5b430 (kmalloc-1024) (1024 bytes) line. But isn't 0000000022a5b430 strange for kmalloc(1024, GFP_KERNEL)ed kernel address? > netlink: 1 bytes leftover after parsing attributes in process `syz-executor5'. > ------------[ cut here ]------------ > kernel BUG at mm/usercopy.c:84! > invalid opcode: 0000 [#1] SMP > Dumping ftrace buffer: > (ftrace buffer empty) > Modules linked in: > CPU: 0 PID: 3943 Comm: syz-executor0 Not tainted 4.15.0-rc3-next-20171214+ #67 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:report_usercopy mm/usercopy.c:76 [inline] > RIP: 0010:__check_object_size+0x1e2/0x250 mm/usercopy.c:276 > RSP: 0018:ffffc90000d6fca8 EFLAGS: 00010292 > RAX: 0000000000000062 RBX: ffffffff82e57be7 RCX: ffffffff8123dede > RDX: 0000000000006340 RSI: ffffc900036c9000 RDI: ffff88021fc136f8 > RBP: ffffc90000d6fce0 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801e076dc50 > R13: 0000000000000400 R14: 0000000000000000 R15: ffffffff82edf8a5 > FS: 00007fe747e20700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 000000002000bffa CR3: 00000001dbd02006 CR4: 00000000001626f0 > DR0: 0000000020000000 DR1: 0000000000010000 DR2: 000000000000f004 > DR3: 0000000000000000 DR6: 00000000fffe0ff3 DR7: 0000000000000600 > Call Trace: > check_object_size include/linux/thread_info.h:112 [inline] > check_copy_size include/linux/thread_info.h:143 [inline] > copy_from_user include/linux/uaccess.h:146 [inline] > memdup_user+0x46/0x90 mm/util.c:168 > kvm_arch_vcpu_ioctl+0xc85/0x1810 arch/x86/kvm/x86.c:3499 > kvm_vcpu_ioctl+0xf3/0x820 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2715 > vfs_ioctl fs/ioctl.c:46 [inline] > do_vfs_ioctl+0xaf/0x840 fs/ioctl.c:686 > SYSC_ioctl fs/ioctl.c:701 [inline] > SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 > entry_SYSCALL_64_fastpath+0x1f/0x96 > RIP: 0033:0x452a09 > RSP: 002b:00007fe747e1fc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452a09 > RDX: 0000000020ebec00 RSI: 000000004400ae8f RDI: 0000000000000019 > RBP: 000000000000023b R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f0628 > R13: 00000000ffffffff R14: 00007fe747e206d4 R15: 0000000000000000 > Code: 7b e5 82 48 0f 44 da e8 8d 82 eb ff 48 8b 45 d0 4d 89 e9 4c 89 e1 4c 89 fa 48 89 de 48 c7 c7 a8 51 e6 82 49 89 c0 e8 76 b7 e3 ff <0f> 0b 48 c7 c0 43 51 e6 82 eb a1 48 c7 c0 53 51 e6 82 eb 98 48 > RIP: report_usercopy mm/usercopy.c:76 [inline] RSP: ffffc90000d6fca8 > RIP: __check_object_size+0x1e2/0x250 mm/usercopy.c:276 RSP: ffffc90000d6fca8 > ---[ end trace 189465b430781fff ]--- > Kernel panic - not syncing: Fatal exception > Dumping ftrace buffer: > (ftrace buffer empty) > Kernel Offset: disabled > Rebooting in 86400 seconds.. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
