>
> On 22 Nov 2018, at 10:55, Alok Makhariya <[email protected]> wrote:
>
> Hi
>
> I have a situation where in some scenarios when VPP is restarted after a
> crash, the VPP which is coming up itself crashes with the following backtrace.
> This does not happen always. Any hints on what could cause this would be
> appreciated.
>
> Backtrace
>
> (gdb) bt
> #0 0x00002b688139c207 in raise () from /lib64/libc.so.6
> #1 0x00002b688139d8f8 in abort () from /lib64/libc.so.6
> #2 0x0000000000405f7e in os_exit (code=code@entry=1) at
> /bfs-build/build-area.49/builds/LinuxNBngp_7.X_RH7/2018-11-16-0505/third-party/vpp/vpp_1801/build-data/../src/vpp/vnet/main.c:292
> #3 0x00002b687f4b09d7 in unix_signal_handler (signum=<optimized out>,
> si=<optimized out>, uc=<optimized out>)
> at
> /bfs-build/build-area.49/builds/LinuxNBngp_7.X_RH7/2018-11-16-0505/third-party/vpp/vpp_1801/build-data/../src/vlib/unix/main.c:120
> #4 <signal handler called>
> #5 rte_mempool_populate_iova_tab (mp=mp@entry=0x1098fbec0,
> vaddr=0x2aaaaac00000 "", iova=0x0, pg_num=<optimized out>,
> pg_shift=<optimized out>, free_cb=free_cb@entry=0x0, opaque=opaque@entry=0x0)
> at
> /bfs-build/build-area.49/builds/LinuxNBngp_7.X_RH7/2018-11-16-0505/third-party/vpp/vpp_1801/build-root/build-vpp-native/dpdk/dpdk-stable-17.11.4/lib/librte_mempool/rte_mempool.c:486
> #6 0x00002b6b0212a373 in dpdk_pool_create (vm=vm@entry=0x2b687f6cb260
> <vlib_global_main>, pool_name=pool_name@entry=0x2b6883a0d924
> "dpdk_mbuf_pool_socket0", elt_size=elt_size@entry=2432,
> num_elts=num_elts@entry=500000,
> pool_priv_size=pool_priv_size@entry=6, cache_size=cache_size@entry=512,
> numa=numa@entry=0 '\000', _mp=_mp@entry=0x2b6884266c68,
> pri=pri@entry=0x2b6884266c5f "")
> at
> /bfs-build/build-area.49/builds/LinuxNBngp_7.X_RH7/2018-11-16-0505/third-party/vpp/vpp_1801/build-data/../src/plugins/dpdk/buffer.c:498
> #7 0x00002b6b0212a470 in dpdk_buffer_pool_create (vm=vm@entry=0x2b687f6cb260
> <vlib_global_main>, num_mbufs=500000, socket_id=0)
> at
> /bfs-build/build-area.49/builds/LinuxNBngp_7.X_RH7/2018-11-16-0505/third-party/vpp/vpp_1801/build-data/../src/plugins/dpdk/buffer.c:537
> #8 0x00002b6b02144861 in dpdk_config (vm=<optimized out>, input=<optimized
> out>)
> at
> /bfs-build/build-area.49/builds/LinuxNBngp_7.X_RH7/2018-11-16-0505/third-party/vpp/vpp_1801/build-data/../src/plugins/dpdk/device/init.c:1288
> #9 0x00002b687f4715ad in vlib_call_all_config_functions (vm=<optimized out>,
> input=input@entry=0x2b6884266fa0, is_early=is_early@entry=0)
> at
> /bfs-build/build-area.49/builds/LinuxNBngp_7.X_RH7/2018-11-16-0505/third-party/vpp/vpp_1801/build-data/../src/vlib/init.c:146
> #10 0x00002b687f479908 in vlib_main (vm=vm@entry=0x2b687f6cb260
> <vlib_global_main>, input=input@entry=0x2b6884266fa0)
> at
> /bfs-build/build-area.49/builds/LinuxNBngp_7.X_RH7/2018-11-16-0505/third-party/vpp/vpp_1801/build-data/../src/vlib/main.c:1772
> #11 0x00002b687f4b0b23 in thread0 (arg=47727814423136) at
> /bfs-build/build-area.49/builds/LinuxNBngp_7.X_RH7/2018-11-16-0505/third-party/vpp/vpp_1801/build-data/../src/vlib/unix/main.c:567
> #12 0x00002b68807e38b8 in clib_calljmp () at
> /bfs-build/build-area.49/builds/LinuxNBngp_7.X_RH7/2018-11-16-0505/third-party/vpp/vpp_1801/build-data/../src/vppinfra/longjmp.S:110
> #13 0x00007ffe03c4a0e0 in ?? ()
> #14 0x00002b687f4b187f in vlib_unix_main (argc=<optimized out>,
> argv=<optimized out>) at
> /bfs-build/build-area.49/builds/LinuxNBngp_7.X_RH7/2018-11-16-0505/third-party/vpp/vpp_1801/build-data/../src/vlib/unix/main.c:631
> #15 0x6f2d326c00000028 in ?? ()
> #16 0x6c632d7475707475 in ?? ()
> #17 0x4c20796669737361 in ?? ()
> #18 0x697373616c432032 in ?? ()
> #19 0x73706f7244207966 in ?? ()
> #20 0x000000006425203a in ?? ()
> #21 0x0000000000000000 in ?? ()
>
>
> VPP version: 18.01
Please move to recent version of vpp 18.01 is not supported anymore.
>
> After analysing back-trace, it is observed that in
> rte_mempool_populate_iova_tab iova address is NULL which is called by
> dpdk_pool_create passing pr->page_table addr as iova address.
> pr : vlib_physmem_region_t *pr;
> Before calling rte_mempool_populate_iova_tab, vlib_physmem_region_alloc is
> called which internally calls vm->os_physmem_region_alloc.
>
> vm->os_physmem_region_alloc is mapped to unix_physmem_region_alloc.
> So in unix_physmem_region_alloc,
> pr->page_table = clib_mem_vm_get_paddr (pr->mem, pr->log2_page_size,
> pr->n_pages);
> Looks like clib_mem_vm_get_paddr is returning NULL to page table address.
>
> Code for clib_mem_vm_get_paddr function
> u64 *
> clib_mem_vm_get_paddr (void *mem, int log2_page_size, int n_pages)
> {
> int pagesize = sysconf (_SC_PAGESIZE);
> int fd;
> int i;
> u64 *r = 0;
>
> if ((fd = open ((char *) "/proc/self/pagemap", O_RDONLY)) == -1)
> return 0;
>
> for (i = 0; i < n_pages; i++)
> {
> u64 seek, pagemap = 0;
> uword vaddr = pointer_to_uword (mem) + (((u64) i) << log2_page_size);
> seek = ((u64) vaddr / pagesize) * sizeof (u64);
> if (lseek (fd, seek, SEEK_SET) != seek)
> goto done;
>
> if (read (fd, &pagemap, sizeof (pagemap)) != (sizeof (pagemap)))
> goto done;
>
> if ((pagemap & (1ULL << 63)) == 0)
> goto done;
>
> pagemap &= pow2_mask (55);
> vec_add1 (r, pagemap * pagesize);
> }
>
> done:
> close (fd);
> if (vec_len (r) != n_pages)
> {
> vec_free (r);
> return 0;
> }
> return r;
> }
>
> So why this could be returning NULL. Any help would be appreciated.
Likely because that is what linux gives back to us by reading
/proc/self/pagemap.
May be permissions issue...
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