[dpdk-dev] dpdk hash lookup function crashed (segment fault)

[张伟]

Hi all, 
When I use the dpdk lookup function, I met the segment fault problem. Can  anybody help to look at why this happens. I will put the aim what I want to do and the related piece of code, and my debug message, 


This problem is that in dpdk multi process - client and server example, dpdk-2.2.0/examples/multi_process/client_server_mp
My aim is that server create a hash table, then share it to client. Client will write the hash  table, server will read the hash table.  I am using dpdk hash table.  What I did is that server create a hash table (table and array entries), return the table address.  I use memzone pass the table address to client.  In client, the second lookup gets segment fault. The system gets crashed.  I will put some related code here. 
create hash table function:

struct onvm_ft*

onvm_ft_create(int cnt, int entry_size) {

        struct rte_hash* hash;

        struct onvm_ft* ft;

        struct rte_hash_parameters ipv4_hash_params = {

            .name = NULL,

            .entries = cnt,

            .key_len = sizeof(struct onvm_ft_ipv4_5tuple),

            .hash_func = NULL,

            .hash_func_init_val = 0,

        };




        char s[64];

        /* create ipv4 hash table. use core number and cycle counter to get a unique name. */

        ipv4_hash_params.name = s;

        ipv4_hash_params.socket_id = rte_socket_id();

        snprintf(s, sizeof(s), "onvm_ft_%d-%"PRIu64, rte_lcore_id(), rte_get_tsc_cycles());

        hash = rte_hash_create(&ipv4_hash_params);

        if (hash == NULL) {

                return NULL;

        }

        ft = (struct onvm_ft*)rte_calloc("table", 1, sizeof(struct onvm_ft), 0);

        if (ft == NULL) {

                rte_hash_free(hash);

                return NULL;

        }

        ft->hash = hash;

        ft->cnt = cnt;

        ft->entry_size = entry_size;

        /* Create data array for storing values */

        ft->data = rte_calloc("entry", cnt, entry_size, 0);

        if (ft->data == NULL) {

                rte_hash_free(hash);

                rte_free(ft);

                return NULL;

        }

        return ft;

}




related structure:

struct onvm_ft {

        struct rte_hash* hash;

        char* data;

        int cnt;

        int entry_size;

};




in server side, I will call the create function, use memzone share it to client. The following is what I do:

related variables:

struct onvm_ft *sdn_ft;

struct onvm_ft **sdn_ft_p;

const struct rte_memzone *mz_ftp;




        sdn_ft = onvm_ft_create(1024, sizeof(struct onvm_flow_entry));

        if(sdn_ft == NULL) {

                rte_exit(EXIT_FAILURE, "Unable to create flow table\n");

        }

        mz_ftp = rte_memzone_reserve(MZ_FTP_INFO, sizeof(struct onvm_ft *),

                                  rte_socket_id(), NO_FLAGS);

        if (mz_ftp == NULL) {

                rte_exit(EXIT_FAILURE, "Canot reserve memory zone for flow table pointer\n");

        }

        memset(mz_ftp->addr, 0, sizeof(struct onvm_ft *));

        sdn_ft_p = mz_ftp->addr;

        *sdn_ft_p = sdn_ft;




In client side:

struct onvm_ft *sdn_ft;

static void

map_flow_table(void) {

        const struct rte_memzone *mz_ftp;

        struct onvm_ft **ftp;




        mz_ftp = rte_memzone_lookup(MZ_FTP_INFO);

        if (mz_ftp == NULL)

                rte_exit(EXIT_FAILURE, "Cannot get flow table pointer\n");

        ftp = mz_ftp->addr;

        sdn_ft = *ftp;

}




The following is my debug message: I set a breakpoint in lookup table line. To narrow down the problem, I just send one flow. So the second time and the first time, the packets are the same.  

For the first time, it works. I print out the parameters: inside the onvm_ft_lookup function, if there is a related entry, it will return the address by flow_entry. 

Breakpoint 1, datapath_handle_read (dp=0x7ffff00008c0) at /home/zhangwei1984/openNetVM-master/openNetVM/examples/flow_table/sdn.c:191

191                                 ret = onvm_ft_lookup(sdn_ft, fk, (char**)&flow_entry);

(gdb) print *sdn_ft 

$1 = {hash = 0x7fff32cce740, data = 0x7fff32cb0480 "", cnt = 1024, entry_size = 56}

(gdb) print *fk

$2 = {src_addr = 419496202, dst_addr = 453050634, src_port = 53764, dst_port = 11798, proto = 17 '\021'}

(gdb) s

onvm_ft_lookup (table=0x7fff32cbe4c0, key=0x7fff32b99d00, data=0x7ffff68d2b00) at /home/zhangwei1984/openNetVM-master/openNetVM/onvm/shared/onvm_flow_table.c:151

151 softrss = onvm_softrss(key);

(gdb) n

152         printf("software rss %d\n", softrss);

(gdb) 

software rss 403183624

154         tbl_index = rte_hash_lookup_with_hash(table->hash, (const void *)key, softrss);

(gdb) print table->hash

$3 = (struct rte_hash *) 0x7fff32cce740

(gdb) print *key

$4 = {src_addr = 419496202, dst_addr = 453050634, src_port = 53764, dst_port = 11798, proto = 17 '\021'}

(gdb) print softrss 

$5 = 403183624

(gdb) c




After I hit c, it will do the second lookup,

Breakpoint 1, datapath_handle_read (dp=0x7ffff00008c0) at /home/zhangwei1984/openNetVM-master/openNetVM/examples/flow_table/sdn.c:191

191                                 ret = onvm_ft_lookup(sdn_ft, fk, (char**)&flow_entry);

(gdb) print *sdn_ft


$7 = {hash = 0x7fff32cce740, data = 0x7fff32cb0480 "", cnt = 1024, entry_size = 56}

(gdb) print *fk

$8 = {src_addr = 419496202, dst_addr = 453050634, src_port = 53764, dst_port = 11798, proto = 17 '\021'}

(gdb) s

onvm_ft_lookup (table=0x7fff32cbe4c0, key=0x7fff32b99c00, data=0x7ffff68d2b00) at /home/zhangwei1984/openNetVM-master/openNetVM/onvm/shared/onvm_flow_table.c:151

151 softrss = onvm_softrss(key);

(gdb) n

152         printf("software rss %d\n", softrss);

(gdb) n

software rss 403183624

154         tbl_index = rte_hash_lookup_with_hash(table->hash, (const void *)key, softrss);

(gdb) print table->hash

$9 = (struct rte_hash *) 0x7fff32cce740

(gdb) print *key 

$10 = {src_addr = 419496202, dst_addr = 453050634, src_port = 53764, dst_port = 11798, proto = 17 '\021'}

(gdb) print softrss

$11 = 403183624

(gdb) n





Program received signal SIGSEGV, Segmentation fault.

0x000000000045fb97 in __rte_hash_lookup_bulk ()

(gdb) bt

#0  0x000000000045fb97 in __rte_hash_lookup_bulk ()

#1  0x0000000000000000 in ?? ()




From the debug message, the parameters are exactly the same. I do not know why it has the segmentation fault. 

my lookup function:

int

onvm_ft_lookup(struct onvm_ft* table, struct onvm_ft_ipv4_5tuple *key, char** data) {

        int32_t tbl_index;

        uint32_t softrss;




        softrss = onvm_softrss(key);

        printf("software rss %d\n", softrss);




        tbl_index = rte_hash_lookup_with_hash(table->hash, (const void *)key, softrss);

        if (tbl_index >= 0) {

                *data = onvm_ft_get_data(table, tbl_index);

                return 0;

        }

        else {

                return tbl_index;

        }

}