FCoE測試重啟除錯記錄

StepForwards發表於2023-02-22

環境

CPU:Phytium,S2500/64 C00
核心版本:4.19.90-25.10
網訊網路卡:txgbe
共兩臺裝置,光纖直連

復現步驟

裝置A、B分別執行以下操作,即可復現

modprobe fcoe
systemctl start lldpad
systemctl start fcoe

總結

重啟問題是SCSI儲存模組libfcoe中fcoe_ctlr_timer_work(drivers/scsi/fcoe/fcoe_ctlr.c)函式訪問了非法的記憶體地址,地址異常原因是編碼問題導致,使用結構體強制賦值而忽略了list指標成員的值。

除錯記錄

檢視核心日誌

麒麟4.19.90 25.10版本,開啟CONFIG_FCOE後,載入txgbe系統發生重啟,檢視系統日誌未發現異常資訊,需要抓取串列埠資訊

獲取串列埠資訊

串列埠資訊抓取失敗,核心在bios階段串列埠日誌正常,但核心階段無輸出,根據日誌可知console enable時ttyS1還未建立。(4.19.90 25.10 51.40現象一樣)

[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 當機
4.19.90 51.40 kdump 測試正常

kdump日誌:

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: \xe4\xb8\xad\xe5\x9b\xbd\xe9\x95\xbf\xe5\x9f\x8e\xe7\xa7\x91\xe6\x8a\x80\xe9\x9b\x86\xe5\x9b\xa2\xe8\x82\xa1\xe4\xbb\xbd\xe6\x9c\x89\xe9\x99\x90\xe5\x85\xac\xe5\x8f\xb8 \xe6\x93\x8e\xe5\xa4\xa9EF862/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日誌:

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指標指向fcoe_ctlr_timer_work+0x988/0xd30 , 對應彙編程式碼

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函式對應核心模組drivers/scsi/fcoe/libfcoe.ko
載入libfcoe、libfc模組

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 

測試步驟:

透過在fcoe_ctlr_timer_work函式中增加除錯資訊(scsi/libfc/libfc.ko、scsi/fcoe/libfcoe.ko、scsi/bnx2fc/bnx2fc.ko等模組也新增了除錯資訊)

陪測端
modprobe fcoe
systemctl start lldpad
systemctl start fcoe

被測端
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

由於&rdata->kref(0xfffffffffffffed8) == rdata(0xfffffffffffffec8) + 16
因此程式出錯位置為if (!kref_get_unless_zero(&rdata->kref)) {

可以確定的是&disc->rports連結串列中遍歷出了2個rdata,第2個rdata是一個錯誤的地址,然而根據日誌顯示fc_rport_create-176 rdata 0xffffec6d50468800 lport 0xffffecc562e98a08 rdata只被建立了1次。

值得說明的是任何一次復現問題第2個rdata始終為0xfffffffffffffec8, 在程式碼中新增以下過濾條件:

   list_for_each_entry_rcu(rdata, &disc->rports, peers) {
        if ((long long)rdata == 0xfffffffffffffec8) {
            printk("%s-%d rdata 0x%llx break\n", __func__, __LINE__, (long long) rdata);
            break;
        }

不會觸發重啟問題,但無法確定FCOE功能是否可用,影響域未知,該方案僅用於除錯。
後續測試上述方案依然存在地址異常問題

定位地址異常原因

fcoe_ctlr_vn_add、fc_disc_init、fc_rport_create中定位異常點,新增除錯資訊確定&lport->disc.rports列表是否被正常初始化,並在多處遍歷&lport->disc.rports以確定異常地址0xfffffffffffffec8是何時進入該列表的。

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 %d\n",
            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%llx\n", __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%llx\n",
            __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%llx\n", __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%llx\n", __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

分析定位地址異常原因

定位發現*frport = *fcoe_ctlr_rport(new); 該程式碼執行後遍歷&lport->disc.rports,出現了異常地址節點0xfffffffffffffec8,去掉該程式碼後地址正常

frport = fcoe_ctlr_rport(rdata); frport是rdata(fc_rport_priv)父類結構體fcoe_rportA指標
*frport = *fcoe_ctlr_rport(new);將new(fc_rport_priv)父類結構體fcoe_rportB賦值給rdata(fc_rport_priv)父類結構體fcoe_rportA,但是由於fcoe_rportA.rdata.peers已經加入連結串列&lport->disc.rports,該賦值會破壞fcoe_rportA.rdata.peers指標內容,從而導致&lport->disc.rports中地址異常。


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);
};

解決方案

此處不直接使用強制結構體賦值,替換為結構體成員手動賦值

-       *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);

測試正常,不在重啟,經排查該問題在開源社群版核心已有成熟的補丁方案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 <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

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