On Sat, Nov 26, 2016 at 9:30 AM, Dmitry Vyukov <dvyu...@google.com> wrote: > Hello, > > The following program triggers GPF in eth_header: > > https://gist.githubusercontent.com/dvyukov/613cadf05543b55a419f237e419cd495/raw/5471231523d1a07c3de55f11f87472c2816ee06c/gistfile1.txt > > On commit 16ae16c6e5616c084168740990fc508bda6655d4 (Nov 24). > > BUG: unable to handle kernel paging request at ffffed002d14d74a > IP: [<ffffffff86be3295>] eth_header+0x75/0x260 net/ethernet/eth.c:88 > PGD 7fff6067 [ 50.787819] PUD 7fff5067 > PMD 0 [ 50.787819] > Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN > Modules linked in: > CPU: 2 PID: 6712 Comm: a.out Not tainted 4.9.0-rc6+ #55 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > task: ffff88003a1841c0 task.stack: ffff880034d08000 > RIP: 0010:[<ffffffff86be3295>] [<ffffffff86be3295>] > eth_header+0x75/0x260 net/ethernet/eth.c:88 > RSP: 0018:ffff880034d0eb68 EFLAGS: 00010a03 > RAX: 1ffff1002d14d74a RBX: ffff880168a6ba4a RCX: ffff88006a9c7858 > RDX: 000000000000dd86 RSI: dffffc0000000000 RDI: ffff880168a6ba56 > RBP: ffff880034d0eb98 R08: 0000000000000000 R09: 0000000000000031 > R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000 > R13: ffff88006c208d80 R14: 00000000000086dd R15: ffff88006a9c7858 > FS: 0000000001a02940(0000) GS:ffff88006d000000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffffed002d14d74a CR3: 0000000037373000 CR4: 00000000000006e0 > Stack: > 000000316881ab40 ffff88006a9c76c0 ffff88006881ab40 ffff88006a9c77f8 > 0000000000000000 dffffc0000000000 ffff880034d0ee98 ffffffff86b31af9 > ffffffff8719605c ffff880034d0f0f8 ffffffff000086dd ffffffff86be3220 > Call Trace: > [< inline >] dev_hard_header ./include/linux/netdevice.h:2762 > [<ffffffff86b31af9>] neigh_resolve_output+0x659/0xb20 > net/core/neighbour.c:1302 > [< inline >] dst_neigh_output ./include/net/dst.h:464 > [<ffffffff8719605c>] ip6_finish_output2+0xb3c/0x2500 > net/ipv6/ip6_output.c:121 > [<ffffffff871a0b0b>] ip6_finish_output+0x2eb/0x760 net/ipv6/ip6_output.c:139 > [< inline >] NF_HOOK_COND ./include/linux/netfilter.h:246 > [<ffffffff871a1157>] ip6_output+0x1d7/0x9a0 net/ipv6/ip6_output.c:153 > [< inline >] dst_output ./include/net/dst.h:501 > [<ffffffff873312ea>] ip6_local_out+0x9a/0x180 net/ipv6/output_core.c:170 > [<ffffffff871a3886>] ip6_send_skb+0xa6/0x340 net/ipv6/ip6_output.c:1712 > [<ffffffff871a3bd8>] ip6_push_pending_frames+0xb8/0xe0 > net/ipv6/ip6_output.c:1732 > [< inline >] rawv6_push_pending_frames net/ipv6/raw.c:607 > [<ffffffff8722acfb>] rawv6_sendmsg+0x250b/0x2c20 net/ipv6/raw.c:920 > [<ffffffff8701c4f5>] inet_sendmsg+0x385/0x590 net/ipv4/af_inet.c:734 > [< inline >] sock_sendmsg_nosec net/socket.c:621 > [<ffffffff86a6ea9f>] sock_sendmsg+0xcf/0x110 net/socket.c:631 > [<ffffffff86a6ee0b>] sock_write_iter+0x32b/0x620 net/socket.c:829 > [<ffffffff81a6f153>] do_iter_readv_writev+0x363/0x670 fs/read_write.c:695 > [<ffffffff81a71ba1>] do_readv_writev+0x431/0x9b0 fs/read_write.c:872 > [<ffffffff81a726dc>] vfs_writev+0x8c/0xc0 fs/read_write.c:911 > [<ffffffff81a72825>] do_writev+0x115/0x2d0 fs/read_write.c:944 > [< inline >] SYSC_writev fs/read_write.c:1017 > [<ffffffff81a75fdc>] SyS_writev+0x2c/0x40 fs/read_write.c:1014 > [<ffffffff8814cf85>] entry_SYSCALL_64_fastpath+0x23/0xc6 > arch/x86/entry/entry_64.S:209 > Code: 41 83 fe 04 0f 84 aa 00 00 00 e8 17 4e b0 fa 48 8d 7b 0c 48 be > 00 00 00 00 00 fc ff df 44 89 f2 66 c1 c2 08 48 89 f8 48 c1 e8 03 <0f> > b6 0c 30 48 8d 43 0d 49 89 c0 49 c1 e8 03 41 0f b6 34 30 49 > RIP [<ffffffff86be3295>] eth_header+0x75/0x260 net/ethernet/eth.c:88 > RSP <ffff880034d0eb68> > CR2: ffffed002d14d74a > ---[ end trace a73fedfdc11bd60c ]---
Hi Dmitry I could not reproduce the issue. Might need some specific configuration... loopback device has proper ethernet header (all 0) Fault happens in : 0f b6 0c 30 movzbl (%rax,%rsi,1),%ecx RAX=1ffff1002d14d74a which is RDI>>3, and RSI=dffffc0000000000 Could this be a KASAN problem ?
