On Fri, Jul 06, 2018 at 03:39:04PM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 526674536360 Add linux-next specific files for 20180706 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=12d51a2c400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=c8d1cfc0cb798e48 > dashboard link: https://syzkaller.appspot.com/bug?extid=4b712dce5cbce6700f27 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=14b05afc400000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17594968400000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+4b712dce5cbce6700f27@xxxxxxxxxxxxxxxxxxxxxxxxx > > IPv6: ADDRCONF(NETDEV_CHANGE): bond0: link becomes ready > IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready > 8021q: adding VLAN 0 to HW filter on device team0 > usercopy: Kernel memory exposure attempt detected from SLAB object > 'kmalloc-4096' (offset 2399, size 2626)! > ------------[ cut here ]------------ > kernel BUG at mm/usercopy.c:100! > invalid opcode: 0000 [#1] SMP KASAN > CPU: 1 PID: 4718 Comm: syz-executor688 Not tainted 4.18.0-rc3-next-20180706+ > #1 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > RIP: 0010:usercopy_abort+0xbb/0xbd mm/usercopy.c:88 > Code: c0 e8 37 ec b8 ff ff 75 c8 48 8b 55 c0 4d 89 f9 ff 75 d0 4d 89 e8 48 > 89 d9 4c 89 e6 41 56 48 c7 c7 e0 4c f3 87 e8 37 a0 9f ff <0f> 0b e8 0c ec b8 > ff e8 97 42 f7 ff 4c 89 e1 8b 95 14 ff ff ff 31 > RSP: 0018:ffff8801d33a78b0 EFLAGS: 00010286 > RAX: 000000000000006b RBX: ffffffff88c10e70 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffffffff81634381 RDI: 0000000000000001 > RBP: ffff8801d33a7908 R08: ffff8801d1e2a200 R09: ffffed003b5e4fc0 > R10: ffffed003b5e4fc0 R11: ffff8801daf27e07 R12: ffffffff87f34bc0 > R13: ffffffff87f34a80 R14: ffffffff87f34a40 R15: ffffffff88c0c905 > FS: 00007f56a6072700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000020001000 CR3: 00000001b8fdf000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > __check_heap_object+0xb5/0xb5 mm/slab.c:4445 > check_heap_object mm/usercopy.c:236 [inline] > __check_object_size+0x4db/0x5f2 mm/usercopy.c:259 > check_object_size include/linux/thread_info.h:119 [inline] > check_copy_size include/linux/thread_info.h:150 [inline] > copy_to_user include/linux/uaccess.h:154 [inline] > seq_read+0x578/0x10e0 fs/seq_file.c:211 > do_loop_readv_writev fs/read_write.c:700 [inline] > do_iter_read+0x49e/0x650 fs/read_write.c:924 > vfs_readv+0x175/0x1c0 fs/read_write.c:986 > do_readv+0x11a/0x310 fs/read_write.c:1019 > __do_sys_readv fs/read_write.c:1106 [inline] > __se_sys_readv fs/read_write.c:1103 [inline] > __x64_sys_readv+0x75/0xb0 fs/read_write.c:1103 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x446c09 > Code: e8 1c bc 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 > 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff > 0f 83 5b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f56a6071d18 EFLAGS: 00000246 ORIG_RAX: 0000000000000013 > RAX: ffffffffffffffda RBX: 00000000006dcc5c RCX: 0000000000446c09 > RDX: 0000000000000002 RSI: 00000000200021c0 RDI: 0000000000000005 > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dcc58 > R13: 00007f56a6071d20 R14: 6f72746e6f632f2e R15: 0000000000000007 > Modules linked in: > Dumping ftrace buffer: > (ftrace buffer empty) > ---[ end trace 532b9c3f493b2e4d ]--- > RIP: 0010:usercopy_abort+0xbb/0xbd mm/usercopy.c:88 > Code: c0 e8 37 ec b8 ff ff 75 c8 48 8b 55 c0 4d 89 f9 ff 75 d0 4d 89 e8 48 > 89 d9 4c 89 e6 41 56 48 c7 c7 e0 4c f3 87 e8 37 a0 9f ff <0f> 0b e8 0c ec b8 > ff e8 97 42 f7 ff 4c 89 e1 8b 95 14 ff ff ff 31 > RSP: 0018:ffff8801d33a78b0 EFLAGS: 00010286 > RAX: 000000000000006b RBX: ffffffff88c10e70 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffffffff81634381 RDI: 0000000000000001 > RBP: ffff8801d33a7908 R08: ffff8801d1e2a200 R09: ffffed003b5e4fc0 > R10: ffffed003b5e4fc0 R11: ffff8801daf27e07 R12: ffffffff87f34bc0 > R13: ffffffff87f34a80 R14: ffffffff87f34a40 R15: ffffffff88c0c905 > FS: 00007f56a6072700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000020001000 CR3: 00000001b8fdf000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Fixed in -mm and linux-next by: #syz fix: VFS: seq_file: ensure ->from is valid - Eric
