<>[  503.347297] CPU

<>[  503.347300] Modules linked in: caq_sendmsg(EN) mysendmsg(EN) witdriver(EN) datalink(EN) w83627dhg(EN) tipc(EX) ossmod(EN) pagecachelimit(EN) xfs ip6table_filter ip6_tables iptable_filter ip_tables ebtable_nat ebtables x_tables ipmi_devintf ipmi_si ipmi_msghandler edd cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq mperf af_packet bonding fuse loop dm_mod vhost_net macvtap ipv6 ipv6_lib macvlan tun kvm_intel kvm pcspkr ses enclosure usbhid hid i40e(EX) sg igb i2c_i801 iTCO_wdt iTCO_vendor_support mei dca mptctl ptp pps_core mptbase rtc_cmos acpi_power_meter container button ext3 jbd mbcache ttm drm_kms_helper drm i2c_algo_bit sysimgblt sysfillrect i2c_core syscopyarea ehci_hcd usbcore usb_common sd_mod crc_t10dif processor thermal_sys hwmon scsi_dh_hp_sw scsi_dh_alua scsi_dh_rdac scsi_dh_emc scsi_dh mpt3sas(EX) configfs scsi_transport_sas raid_class scsi_mod

<>[  503.347404] Supported: No, Unsupported modules are loaded

<>[  503.347408]

<>[  503.347413] Pid: , comm: -IFileSender Tainted: G           ENX 3.0.-0.47.-default # ZTE Grantley/S1008

<>[  503.347422] RIP: :[<ffffffff813e9830>]  [<ffffffff813e9830>] get_page+0x0/0x30

<>[  503.347434] RSP: :ffff88334a88b4e0  EFLAGS:

<>[  503.347438] RAX: ffffffff81a77be0 RBX: ffff88198c904b80 RCX: ffff881f76b3b3f0

<>[  503.347443] RDX:  RSI: 0000000000003ebc RDI:

<>[  503.347449] RBP: ffff881f76b3b300 R08:  R09:

<>[  503.347453] R10:  R11:  R12:

<>[  503.347458] R13:  R14:  R15:

<>[  503.347464] FS:  00007f3678a69700() GS:ffff88207fc00000() knlGS:

<>[  503.347470] CS:   DS:  ES:  CR0:

<>[  503.347474] CR2: 00007f3659bcceac CR3: 00000034bfc1e000 CR4: 00000000001407f0

<>[  503.347479] DR0:  DR1:  DR2:

<>[  503.347484] DR3:  DR6: 00000000ffff0ff0 DR7:

<>[  503.347490] Process -IFileSender (pid: , threadinfo ffff88334a88a000, task ffff88334a888540)

<>[  503.347495] Stack:

<>[  503.347498]  ffffffff813eb098 000000004a88b5d8 ffff882000000000

<>[  503.347510]  ffff883300000000 000000007ffd9e00

<>[  503.347519]  000000004a888e50 ffffea005c719dd8 000005b4000000d0 ffff88198c904c88

<>[  503.347528] Call Trace:

<>[  503.347541]  [<ffffffff813eb098>] do_tcp_sendpages+0x438/0x530

<>[  503.347556]  [<ffffffffa06ed4cd>] caq_sendmsg_for_file+0x20d/0x480 [caq_sendmsg]

<>[  503.347583]  [<ffffffffa06ee574>] sendmsg_for_file+0x154/0x220 [caq_sendmsg]

<>[  503.347594]  [<ffffffffa06ee801>] my_sys_sendmsg+0x1c1/0x208 [caq_sendmsg]

<>[  503.347608]  [<ffffffff8146f5f2>] system_call_fastpath+0x16/0x1b

<>[  503.347621]  [<00007f36ad754e4d>] 0x7f36ad754e4c

int tcp_sendpage(struct sock *sk, struct page *page, int offset,

         size_t size, int flags)

{

    ssize_t res;

    if (!(sk->sk_route_caps & NETIF_F_SG) ||

        !(sk->sk_route_caps & NETIF_F_ALL_CSUM))

        return sock_no_sendpage(sk->sk_socket, page, offset, size,

                    flags);

    lock_sock(sk);

    res = do_tcp_sendpages(sk, &page, offset, size, flags);

    release_sock(sk);

    return res;

}

而对应的3.10版本，则是如下：

int tcp_sendpage(struct sock *sk, struct page *page, int offset,

         size_t size, int flags)

{

    ssize_t res;

    if (!(sk->sk_route_caps & NETIF_F_SG) ||

        !(sk->sk_route_caps & NETIF_F_CSUM_MASK))

        return sock_no_sendpage(sk->sk_socket, page, offset, size,

                    flags);

    lock_sock(sk);

    res = do_tcp_sendpages(sk, page, offset, size, flags);

    release_sock(sk);

    return res;

}

一开始从crash排查，发现传入的page是NULL指针，然后开始在入参之前检查，发现bug_on没有触发。

最后通过merge代码，发现suse11的do_tcp_sendpages 和cgslv5的 do_tcp_sendpages 的定义不一样，第二个参数，高版本的不需要取地址，低版本需要取page的地址。

为了这么低级的bug查了几个小时，哎。

总结：

不同内核版本移植模块的时候，对于修改的代码，最好先对比下函数，防止犯低级错误。