- A+
所属分类：linux技术
环境
CPU:Phytium,S2500/64 C00
内核版本：4.19.90-25.10
网讯网卡：txgbe
共两台设备，光纤直连
复现步骤
设备A、B分别执行以下操作，即可复现
modprobe fcoe systemctl start lldpad systemctl start fcoe 总结
重启问题是SCSI存储模块libfcoe中fcoe_ctlr_timer_work（drivers/scsi/fcoe/fcoe_ctlr.c）函数访问了非法的内存地址，地址异常原因是编码问题导致，使用结构体强制赋值而忽略了list指针成员的值。
调试记录
查看内核日志
麒麟4.19.90 25.10版本，开启CONFIG_FCOE后，加载txgbe系统发生重启，查看系统日志未发现异常信息，需要抓取串口信息
获取串口信息
串口信息抓取失败，内核在bios阶段串口日志正常，但内核阶段无输出，根据日志可知console enable时ttyS1还未创建。（4.19.90 25.10 51.40现象一样）
[root@compute ~]# dmesg | grep tty [ 0.000000] Kernel command line: BOOT_IMAGE=/vmlinuz-4.19.90-51.0.v2207.fortest.ky10.aarch64 root=/dev/mapper/klas-root ro crashkernel=auto rd.lvm.lv=klas/root rd.lvm.lv=klas/swap acpi=on video=VGA-1:640x480-32@60me smmu.bypassdev=0x1000:0x17 smmu.bypassdev=0x1000:0x15 crashkernel=1024M,high video=efifb:off video=VGA-1:640x480-32@60me console=ttyS1,115200 loglevel=7 [ 14.695352] 00:02: ttyS0 at MMIO 0x200002f8 (irq = 0, base_baud = 115200) is a 16550A [ 15.478192] console [ttyS0] enabled [ 15.479627] HISI0031:00: ttyS1 at MMIO 0x28001000 (irq = 7, base_baud = 3125000) is a 16550A [ 90.445804] audit: type=1300 audit(1676610550.480:126): arch=c00000b7 syscall=105 success=yes exit=0 a0=aaaaf7e3bcb0 a1=2ab7 a2=aaaae0aff1c8 a3=aaaaf7e322d0 items=0 ppid=3107 pid=5502 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="modprobe" exe="/usr/bin/kmod" key=(null) [ 182.268682] audit: type=1006 audit(1676610660.130:141): pid=5598 uid=0 old-auid=4294967295 auid=0 tty=(none) old-ses=4294967295 ses=1 res=1 [ 333.116270] audit: type=1006 audit(1676610810.970:231): pid=6326 uid=0 old-auid=4294967295 auid=0 tty=(none) old-ses=4294967295 ses=3 res=1 使用kdump
kdump部署命令:
yum install -y kexec-tools systemctl restart kdump.service kdumpctl restart 4.19.90 25.10 kdump 宕机
4.19.90 51.40 kdump 测试正常
kdump日志：
1950 [ 811.607882] Unable to handle kernel paging request at virtual address fffffffffffffed8 1951 [ 811.608613] Mem abort info: 1952 [ 811.608882] ESR = 0x96000005 1953 [ 811.609175] Exception class = DABT (current EL), IL = 32 bits 1954 [ 811.609697] SET = 0, FnV = 0 1955 [ 811.609989] EA = 0, S1PTW = 0 1956 [ 811.610285] Data abort info: 1957 [ 811.610576] ISV = 0, ISS = 0x00000005 1958 [ 811.610933] CM = 0, WnR = 0 1959 [ 811.611219] swapper pgtable: 64k pages, 48-bit VAs, pgdp = 000000003e78cc5f 1960 [ 811.611855] [fffffffffffffed8] pgd=0000000000000000, pud=0000000000000000 1961 [ 811.612454] Internal error: Oops: 96000005 [#1] SMP 1962 [ 811.612930] Modules linked in: qedf qed crc8 fcoe libfcoe libfc scsi_transport_fc xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 ip6table_mangle ip6table_nat iptable_mangle iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ip6table_f ilter ip6_tables iptable_filter tun ebtable_filter ebtable_nat ebtables iptable_raw iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi br_netfilter bridge 8021q garp mrp ipmi_ssif stp rfkill llc sunrpc vfat fat aes_ce_blk crypto_simd cryptd aes_ce_cipher crct10dif _ce ghash_ce joydev ch341 ses sha2_ce usbserial sha256_arm64 enclosure txgbe ngbe sha1_ce sbsa_gwdt ipmi_si ipmi_devintf ipmi_msghandler sch_fq_codel ip_tables megaraid_sas ast dm_mirror dm_region_hash dm_log gb 1963 [ 811.618343] Process kworker/6:2 (pid: 1264, stack limit = 0x0000000070e328c3) 1964 [ 811.618970] CPU: 6 PID: 1264 Comm: kworker/6:2 Kdump: loaded Not tainted 4.19.90-51.0.v2207.fortest.ky10.aarch64 #1 1965 [ 811.619951] Source Version: 8a40033b0116040c501be072732bf7ac6ebdb4f7 1966 [ 811.620504] Hardware name: xe4xb8xadxe5x9bxbdxe9x95xbfxe5x9fx8exe7xa7x91xe6x8ax80xe9x9bx86xe5x9bxa2xe8x82xa1xe4xbbxbdxe6x9cx89xe9x99x90xe5x85xacxe5x8fxb8 xe6x93x8exe5xa4xa9EF862/GW-748E2A-FTG, 1967 [ 811.621673] Workqueue: events fcoe_ctlr_timer_work [libfcoe] 1968 [ 811.622203] pstate: a0000005 (NzCv daif -PAN -UAO) 1969 [ 811.622640] pc : fcoe_ctlr_timer_work+0x988/0xd30 [libfcoe] 1970 [ 811.623165] lr : fcoe_ctlr_timer_work+0x934/0xd30 [libfcoe] 1971 [ 811.623698] sp : ffffb5c314a17cf0 1972 [ 811.624001] x29: ffffb5c314a17cf0 x28: ffffb81b23c91a50 1973 [ 811.624518] x27: ffff288838b08910 x26: ffffb81b23c91a68 1974 [ 811.625005] x25: 000000010000c5a1 x24: ffffb7db23311e08 1975 [ 811.625547] x23: ffffb81b23c91a08 x22: ffff2888802b5000 1976 [ 811.626025] x21: ffffb7db23311c80 x20: fffffffffffffec8 1977 [ 811.626543] x19: ffffb5c30f555010 x18: ffffffffffffffff 1978 [ 811.627129] x17: 0000000000000000 x16: 0000000000000000 1979 [ 811.627630] x15: ffff2888802b5a38 x14: ffff288900b6cb8f 1980 [ 811.628112] x13: ffff288880b6cba2 x12: ffff28888092f918 1981 [ 811.628618] x11: 0000000000000040 x10: ffff288880927e40 1982 [ 811.629086] x9 : ffff288880927e38 x8 : ffffb5bb0000c8e8 1983 [ 811.629561] x7 : fefefefefefefeff x6 : 0000000000000000 1984 [ 811.630027] x5 : 000073746e657665 x4 : 0000000000000006 1985 [ 811.630499] x3 : 0000000000000000 x2 : ffffb5c3144c7200 1986 [ 811.631000] x1 : 0000000000000000 x0 : 0000000000000000 1987 [ 811.631474] Call trace: 1988 [ 811.631753] fcoe_ctlr_timer_work+0x988/0xd30 [libfcoe] 1989 [ 811.632238] process_one_work+0x1fc/0x490 1990 [ 811.632655] worker_thread+0x50/0x4b8 1991 [ 811.633001] kthread+0x134/0x138 1992 [ 811.633315] ret_from_fork+0x10/0x18 1993 [ 811.633659] Code: f9409e80 d104e014 eb00039f 540003e0 (b9401283) 1994 [ 811.634313] SMP: stopping secondary CPUs 1995 [ 811.643778] Starting crashdump kernel... 1996 [ 811.644615] Bye! crash日志：
WARNING: kernel relocated [99295086MB]: patching 104404 gdb minimal_symbol values KERNEL: /lib/debug/lib/modules/4.19.90-51.0.v2207.fortest.ky10.aarch64/vmlinux DUMPFILE: /var/crash/127.0.0.1-2023-02-17-11:02:11/vmcore [PARTIAL DUMP] CPUS: 128 DATE: Fri Feb 17 10:58:52 CST 2023 UPTIME: 00:57:06 LOAD AVERAGE: 1.01, 0.23, 0.08 TASKS: 1555 NODENAME: localhost.localdomain RELEASE: 4.19.90-51.0.v2207.fortest.ky10.aarch64 VERSION: #1 SMP Thu Feb 16 14:14:39 CST 2023 MACHINE: aarch64 (unknown Mhz) MEMORY: 127.8 GB PANIC: "Unable to handle kernel paging request at virtual address fffffffffffffed8" PID: 810 COMMAND: "kworker/122:1" TASK: ffff870061ec1300 [THREAD_INFO: ffff870061ec1300] CPU: 122 STATE: TASK_RUNNING (PANIC) crash> pc指针指向fcoe_ctlr_timer_work+0x988/0xd30 , 对应汇编代码
crash> bt PID: 810 TASK: ffff870061ec1300 CPU: 122 COMMAND: "kworker/122:1" #0 [ffff870061f3f7e0] machine_kexec at ffff5eb1feed40c4 #1 [ffff870061f3f840] __crash_kexec at ffff5eb1feff4708 #2 [ffff870061f3f9d0] crash_kexec at ffff5eb1feff4830 #3 [ffff870061f3fa00] die at ffff5eb1feebfe9c #4 [ffff870061f3fa40] die_kernel_fault at ffff5eb1feee3634 #5 [ffff870061f3fa70] __do_kernel_fault at ffff5eb1feee32d8 #6 [ffff870061f3faa0] do_translation_fault at ffff5eb1ffb0c22c #7 [ffff870061f3fad0] do_mem_abort at ffff5eb1feeb130c #8 [ffff870061f3fcd0] el1_ia at ffff5eb1feeb310c PC: ffff5eb1bd8d513c [fcoe_ctlr_timer_work+3180] LR: ffff5eb1bd8d513c [fcoe_ctlr_timer_work+3180] SP: ffff870061f3fce0 PSTATE: 40000005 X29: ffff870061f3fce0 X28: ffff84a8510d1410 X27: ffff5eb1bd8e0e98 X26: fffffffffffffec8 X25: ffff5eb1bd8e0248 X24: ffff8700630cc480 X23: 000000010004c592 X22: ffff5eb1bd8e0000 X21: ffff5eb1bd8e0000 X20: ffff8700630cc608 X19: ffff5eb200135000 X18: ffffffffffffffff X17: 0000000000000001 X16: 0000000000000007 X15: ffff5eb200135a38 X14: ffff5eb2809ecb8f X13: ffff5eb2009ecba2 X12: ffff5eb2007af918 X11: 0000000005f5e0ff X10: ffff5eb200785b70 X9: ffff5eb200350018 X8: ffff5eb1ff63f658 X7: 6c74635f656f6366 X6: 0000000000000773 X5: ffff8709fc3a1500 X4: 0000000000000006 X3: ffff8709fc3a1500 X2: 32ccc9c32ff8a200 X1: 0000000000000000 X0: 0000000000000017 #9 [ffff870061f3fce0] fcoe_ctlr_timer_work at ffff5eb1bd8d5138 [libfcoe] #10 [ffff870061f3fdb0] process_one_work at ffff5eb1fef477a0 #11 [ffff870061f3fe00] worker_thread at ffff5eb1fef47a84 #12 [ffff870061f3fe70] kthread at ffff5eb1fef4f7e0 crash> dis -l ffff5eb1bd8d513c 0xffff5eb1bd8d513c <fcoe_ctlr_timer_work+3180>: ldr w4, [x26,#16] crash> drivers/scsi/fcoe/fcoe_ctlr.c：fcoe_ctlr_timer_work函数对应内核模块drivers/scsi/fcoe/libfcoe.ko
加载libfcoe、libfc模块
crash> mod -s libfcoe MODULE NAME SIZE OBJECT FILE ffff5eb1bd8f0680 libfcoe 262144 /usr/lib/debug/usr/lib/modules/4.19.90-51.0.v2207.fortest.ky10.aarch64/kernel/drivers/scsi/fcoe/libfcoe.ko.debug crash> mod -s libfc MODULE NAME SIZE OBJECT FILE ffff5369cc050bc0 libfc 327680 /usr/lib/debug/usr/lib/modules/4.19.90-51.0.v2207.fortest.ky10.aarch64/kernel/drivers/scsi/libfc/libfc.ko.debug 测试步骤：
通过在fcoe_ctlr_timer_work函数中增加调试信息(scsi/libfc/libfc.ko、scsi/fcoe/libfcoe.ko、scsi/bnx2fc/bnx2fc.ko等模块也添加了调试信息)
陪测端 modprobe fcoe systemctl start lldpad systemctl start fcoe 被测端 modprobe scsi_transport_fc insmod libfc.ko debug_logging=0xff insmod libfcoe3.ko debug_logging=0xff modprobe cnic insmod bnx2fc.ko debug_logging=0xff modprobe fcoe systemctl start lldpad systemctl start fcoe static void fcoe_ctlr_vn_disc(struct fcoe_ctlr *fip) { struct fc_lport *lport = fip->lp; struct fc_disc *disc = &lport->disc; struct fc_rport_priv *rdata; struct fcoe_rport *frport; void (*callback)(struct fc_lport *, enum fc_disc_event); printk("%s-%d n", __func__, __LINE__); mutex_lock(&disc->disc_mutex); printk("%s-%d n", __func__, __LINE__); callback = disc->pending ? disc->disc_callback : NULL; disc->pending = 0; printk("%s-%d n", __func__, __LINE__); list_for_each_entry_rcu(rdata, &disc->rports, peers) { printk("%s-%d rdata 0x%llx n", __func__, __LINE__, (long long) rdata); if (!kref_get_unless_zero(&rdata->kref)) { printk("%s-%d n", __func__, __LINE__); continue; } ...... [ 1403.774784] fc_rport_create-173 [ 1403.775174] host1: Assigned Port ID 005b49 [ 1403.775483] fc_rport_create-176 rdata 0xffffec6d50468800 lport 0xffffecc562e98a08 [ 1403.775900] host1: lport 005b49: Entered READY from state FLOGI [ 1403.776661] fcoe_ctlr_vn_add-2536 rdata 0xffffec6d50468800 [ 1403.777796] host1: fip: vn_add rport 00f848 new state 0 [ 1403.777804] fcoe_ctlr_timer_work-1820 [ 1403.777811] fcoe_ctlr_timer_work-1822 [ 1403.779145] fcoe_ctlr_timer_work-1824 [ 1403.779607] fcoe_ctlr_vn_timeout-3147 [ 1403.779998] fcoe_ctlr_vn_timeout-3149 [ 1403.780366] fcoe_ctlr_vn_timeout-3178 [ 1403.780766] fcoe_ctlr_vn_timeout-3183 [ 1403.781161] fcoe_ctlr_vn_timeout-3185 [ 1403.781571] fcoe_ctlr_vn_timeout-3196 [ 1403.781971] fcoe_ctlr_vn_disc-3099 [ 1403.782345] fcoe_ctlr_vn_disc-3101 [ 1403.782731] fcoe_ctlr_vn_disc-3104 [ 1403.783096] fcoe_ctlr_vn_disc-3106 rdata 0xffffec6d50468800 [ 1403.784697] fcoe_ctlr_vn_disc-3115 [ 1403.785090] fcoe_ctlr_vn_disc-3106 rdata 0xfffffffffffffec8 [ 1403.785621] Unable to handle kernel paging request at virtual address fffffffffffffed8 crash> struct -o fc_rport_priv struct fc_rport_priv { [0] struct fc_lport *local_port; [8] struct fc_rport *rport; [16] struct kref kref; ...... } SIZE: 432 由于&rdata->kref(0xfffffffffffffed8) == rdata(0xfffffffffffffec8) + 16，
因此程序出错位置为if (!kref_get_unless_zero(&rdata->kref)) {
可以确定的是&disc->rports链表中遍历出了2个rdata,第2个rdata是一个错误的地址，然而根据日志显示fc_rport_create-176 rdata 0xffffec6d50468800 lport 0xffffecc562e98a08 rdata只被创建了1次。
值得说明的是任何一次复现问题第2个rdata始终为0xfffffffffffffec8, 在代码中添加以下过滤条件：
list_for_each_entry_rcu(rdata, &disc->rports, peers) { if ((long long)rdata == 0xfffffffffffffec8) { printk("%s-%d rdata 0x%llx breakn", __func__, __LINE__, (long long) rdata); break; } 不会触发重启问题，但无法确定FCOE功能是否可用，影响域未知，该方案仅用于调试。
后续测试上述方案依然存在地址异常问题
定位地址异常原因
在fcoe_ctlr_vn_add、fc_disc_init、fc_rport_create中定位异常点，添加调试信息确定&lport->disc.rports列表是否被正常初始化，并在多处遍历&lport->disc.rports以确定异常地址0xfffffffffffffec8是何时进入该列表的。
drivers/scsi/fcoe/fcoe_ctlr.c
static void fcoe_ctlr_vn_add(struct fcoe_ctlr *fip, struct fc_rport_priv *new) { ... ... frport = fcoe_ctlr_rport(rdata); LIBFCOE_FIP_DBG(fip, "vn_add rport %6.6x %s state %dn", port_id, frport->fcoe_len ? "old" : "new", rdata->rp_state); list_for_each_entry_rcu(tmprdata, &lport->disc.rports, peers) { printk("%s-%d rdata 0x%llx lport 0x%llx rports 0x%llxn", __func__, __LINE__, (long long) tmprdata, (long long) lport, (long long) &lport->disc.rports); } //*frport = *fcoe_ctlr_rport(new); printk("%s-%d frport 0x%llx *frport 0x%llx fcoe_ctlr_rport(new) 0x%llx *fcoe_ctlr_rport(new) 0x%llxn", __func__, __LINE__, (long long) frport, (long long) &(*frport), (long long)(fcoe_ctlr_rport(new)), (long long)&(*fcoe_ctlr_rport(new))); list_for_each_entry_rcu(tmprdata, &lport->disc.rports, peers) { printk("%s-%d rdata 0x%llx lport 0x%llx rports 0x%llxn", __func__, __LINE__, (long long) tmprdata, (long long) lport, (long long) &lport->disc.rports); } frport = fcoe_ctlr_rport(new); frport->time = 0; list_for_each_entry_rcu(tmprdata, &lport->disc.rports, peers) { printk("%s-%d rdata 0x%llx lport 0x%llx rports 0x%llxn", __func__, __LINE__, (long long) tmprdata, (long long) lport, (long long) &lport->disc.rports); } } [ 1437.536857] fc_rport_create-182 rdata 0xffffd1aa9dedf400 lport 0xffffd202a4a0da08 rports 0xffffd202a4a0da50 [ 1437.538199] fcoe_ctlr_vn_add-2527 rdata 0xffffd1aa9dedf400 lport 0xffffd202a4a0da08 rports 0xffffd202a4a0da50 [ 1437.539130] fcoe_ctlr_vn_add-2540 rdata 0xffffd1aa9dedf400 lport 0xffffd202a4a0da08 rports 0xffffd202a4a0da50 [ 1437.539963] fcoe_ctlr_vn_add-2554 rdata 0xffffd1aa9dedf400 lport 0xffffd202a4a0da08 rports 0xffffd202a4a0da50 [ 1437.540916] fcoe_ctlr_vn_add-2560 frport 0xffffd1aa9dedf400 *frport 0xffffd1aa9dedf400 fcoe_ctlr_rport(new) 0xffffd1aa8b04bb28 *fcoe_ctlr_rport(new) 0xffffd1aa8b04bb28 [ 1437.542148] fcoe_ctlr_vn_add-2563 rdata 0xffffd1aa9dedf400 lport 0xffffd202a4a0da08 rports 0xffffd202a4a0da50 分析定位地址异常原因
定位发现*frport = *fcoe_ctlr_rport(new); 该代码执行后遍历&lport->disc.rports，出现了异常地址节点0xfffffffffffffec8,去掉该代码后地址正常
frport = fcoe_ctlr_rport(rdata); frport是rdata（fc_rport_priv）父类结构体fcoe_rportA指针
*frport = *fcoe_ctlr_rport(new);将new(fc_rport_priv)父类结构体fcoe_rportB赋值给rdata（fc_rport_priv）父类结构体fcoe_rportA，但是由于fcoe_rportA.rdata.peers已经加入链表&lport->disc.rports,该赋值会破坏fcoe_rportA.rdata.peers指针内容，从而导致&lport->disc.rports中地址异常。
static inline struct fcoe_rport *fcoe_ctlr_rport(struct fc_rport_priv *rdata) { return container_of(rdata, struct fcoe_rport, rdata); } struct fcoe_rport { struct fc_rport_priv rdata; unsigned long time; u16 fcoe_len; u16 flags; u8 login_count; u8 enode_mac[ETH_ALEN]; u8 vn_mac[ETH_ALEN]; }; struct fc_rport_priv { struct fc_lport *local_port; struct fc_rport *rport; struct kref kref; enum fc_rport_state rp_state; struct fc_rport_identifiers ids; u16 flags; u16 max_seq; u16 disc_id; u16 maxframe_size; unsigned int retries; unsigned int major_retries; unsigned int e_d_tov; unsigned int r_a_tov; struct mutex rp_mutex; struct delayed_work retry_work; enum fc_rport_event event; struct fc_rport_operations *ops; struct list_head peers; struct work_struct event_work; u32 supported_classes; u16 prli_count; struct rcu_head rcu; u16 sp_features; u8 spp_type; void (*lld_event_callback)(struct fc_lport *, struct fc_rport_priv *, enum fc_rport_event); }; 解决方案
此处不直接使用强制结构体赋值，替换为结构体成员手动赋值
- *frport = *fcoe_ctlr_rport(new); + frport->fcoe_len = new->fcoe_len; + frport->flags = new->flags; + frport->login_count = new->login_count; + memcpy(frport->enode_mac, new->enode_mac, ETH_ALEN); + memcpy(frport->vn_mac, new->vn_mac, ETH_ALEN); 测试正常，不在重启，经排查该问题在开源社区版内核已有成熟的补丁方案https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d478418703d6bcdd163d5d8127683c6c471539f0
scsi: fcoe: pass in fcoe_rport structure instead of fc_rport_priv Instead of using the generic 'fc_rport_priv' structure as argument and then having to painstakingly outcast this to fcoe_rport we should be passing the fcoe_rport structure itself and reduce complexity. Signed-off-by: Hannes Reinecke <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Signed-off-by: Martin K. Petersen <[email protected]> 
