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
在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>