Hi Maxime,

On 5/2/2018 4:34 PM, Maxime Coquelin wrote:
Hi Jiangfeng,

On 05/02/2018 10:19 AM, Tan, Jianfeng wrote:


On 5/1/2018 2:46 AM, Olivier Matz wrote:
Hi Maxime,

Le 30 avril 2018 17:45:52 GMT+02:00, Maxime Coquelin <maxime.coque...@redhat.com> a écrit :
Hi Olivier,

On 04/24/2018 04:46 PM, Olivier Matz wrote:
Some parts of dpdk use their own management threads. Most of the
time,
the affinity of the thread is not properly set: it should not be
scheduled
on the dataplane cores, because interrupting them can cause packet
losses.
This patchset introduces a new wrapper for thread creation that does
the job automatically, avoiding code duplication.

v3:
* new patch: use this API in examples when relevant.
* replace pthread_kill by pthread_cancel. Note that pthread_join()
    is still needed.
* rebase: vfio and pdump do not have control pthreads anymore, and
eal
    has 2 new pthreads
* remove all calls to snprintf/strlcpy that truncate the thread name:
    all strings lengths are already < 16.

v2:
* set affinity to master core if no core is off, as suggested by
    Anatoly

Olivier Matz (5):
    eal: use sizeof to avoid a double use of a define
    eal: new function to create control threads
    eal: set name when creating a control thread
    eal: set affinity for control threads
    examples: use new API to create control threads

   drivers/net/kni/Makefile                     |  1 +
   drivers/net/kni/rte_eth_kni.c                |  3 +-
   examples/tep_termination/main.c              | 16 +++----
   examples/vhost/main.c                        | 19 +++-----
   lib/librte_eal/bsdapp/eal/eal.c              |  4 +-
   lib/librte_eal/bsdapp/eal/eal_thread.c       |  2 +-
   lib/librte_eal/common/eal_common_proc.c      | 15 ++----
   lib/librte_eal/common/eal_common_thread.c    | 72
++++++++++++++++++++++++++++
lib/librte_eal/common/include/rte_lcore.h    | 26 ++++++++++
   lib/librte_eal/linuxapp/eal/eal.c            |  4 +-
   lib/librte_eal/linuxapp/eal/eal_interrupts.c | 17 ++-----
   lib/librte_eal/linuxapp/eal/eal_thread.c     |  2 +-
   lib/librte_eal/linuxapp/eal/eal_timer.c      | 12 +----
   lib/librte_eal/rte_eal_version.map           |  1 +
   lib/librte_vhost/socket.c                    | 25 ++--------
   15 files changed, 135 insertions(+), 84 deletions(-)

I face a deadlock issue with your series, that Jianfeng patch does not
resolve ("eal: fix threads block on barrier"). Reverting the series and
Jianfeng patch makes the issue to disappear.

I face the problem in a VM (not seen on the host):
# ./install/bin/testpmd -l 0,1,2 --socket-mem 1024 -n 4 --proc-type
auto
--file-prefix pg -- --portmask=3 --forward-mode=macswap
--port-topology=chained --disable-rss -i --rxq=1 --txq=1 --rxd=256
--txd=256 --nb-cores=2 --auto-start
EAL: Detected 3 lcore(s)
EAL: Detected 1 NUMA nodes
EAL: Auto-detected process type: PRIMARY
EAL: Multi-process socket /var/run/.pg_unix


Then it is stuck. Attaching with GDB, I get below backtrace
information:

(gdb) info threads
   Id   Target Id         Frame
   3    Thread 0x7f63e1f9f700 (LWP 8808) "rte_mp_handle"
0x00007f63e2591bfd in recvmsg () at
../sysdeps/unix/syscall-template.S:81
   2    Thread 0x7f63e179e700 (LWP 8809) "rte_mp_async"
pthread_barrier_wait () at
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S:71
* 1    Thread 0x7f63e32cec00 (LWP 8807) "testpmd" pthread_barrier_wait
() at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S:71
(gdb) bt full
#0  pthread_barrier_wait () at
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S:71
No locals.
#1  0x0000000000520c54 in rte_ctrl_thread_create
(thread=thread@entry=0x7ffe5c895020, name=name@entry=0x869d86
"rte_mp_async", attr=attr@entry=0x0,
start_routine=start_routine@entry=0x521030 <async_reply_handle>,
arg=arg@entry=0x0)
     at /root/src/dpdk/lib/librte_eal/common/eal_common_thread.c:207
         params = 0x17b1e40
         lcore_id = <optimized out>
         cpuset = {__bits = {1, 0 <repeats 15 times>}}
         cpu_found = <optimized out>
         ret = 0
#2  0x00000000005220b6 in rte_mp_channel_init () at
/root/src/dpdk/lib/librte_eal/common/eal_common_proc.c:674
path = "/var/run\000.pg_unix_*", '\000' <repeats 1301 times>...
         dir_fd = 4
         mp_handle_tid = 140066969745152
         async_reply_handle_tid = 140066961352448
#3  0x000000000050c227 in rte_eal_init (argc=argc@entry=23,
argv=argv@entry=0x7ffe5c896378) at
/root/src/dpdk/lib/librte_eal/linuxapp/eal/eal.c:775
         i = <optimized out>
         fctret = 11
         ret = <optimized out>
         thread_id = 140066989861888
         run_once = {cnt = 1}
         logid = 0x17b1e00 "testpmd"
         cpuset = "T}\211\\\376\177", '\000' <repeats 117 times>,
"\020", '\000' <repeats 116 times>...
thread_name = "X}\211\\\376\177\000\000\226\301\036\342c\177\000"
         __func__ = "rte_eal_init"
#4  0x0000000000473214 in main (argc=23, argv=0x7ffe5c896378) at
/root/src/dpdk/app/test-pmd/testpmd.c:2597
         diag = <optimized out>
         port_id = <optimized out>
         ret = <optimized out>
         __func__ = "main"
(gdb) thread 2
[Switching to thread 2 (Thread 0x7f63e179e700 (LWP 8809))]
#0  pthread_barrier_wait () at
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S:71
71        cmpl    %edx, (%rdi)
(gdb) bt full
#0  pthread_barrier_wait () at
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S:71
No locals.
#1  0x0000000000520777 in rte_thread_init (arg=<optimized out>) at
/root/src/dpdk/lib/librte_eal/common/eal_common_thread.c:156
         params = <optimized out>
         start_routine = 0x521030 <async_reply_handle>
         routine_arg = 0x0
#2  0x00007f63e258add5 in start_thread (arg=0x7f63e179e700) at
pthread_create.c:308
         __res = <optimized out>
         pd = 0x7f63e179e700
         now = <optimized out>
         unwind_buf = {cancel_jmp_buf = {{jmp_buf = {140066961352448,
1212869169857371576, 0, 8392704, 0, 140066961352448,
-1291626103561052744, -1291619793368703560}, mask_was_saved = 0}}, priv

= {pad = {0x0, 0x0, 0x0, 0x0}, data = {
               prev = 0x0, cleanup = 0x0, canceltype = 0}}}
         not_first_call = <optimized out>
         pagesize_m1 = <optimized out>
         sp = <optimized out>
         freesize = <optimized out>
#3  0x00007f63e22b4b3d in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:113
No locals.
(gdb) thread 3
[Switching to thread 3 (Thread 0x7f63e1f9f700 (LWP 8808))]
#0  0x00007f63e2591bfd in recvmsg () at
../sysdeps/unix/syscall-template.S:81
81    T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
(gdb) bt full
#0  0x00007f63e2591bfd in recvmsg () at
../sysdeps/unix/syscall-template.S:81
No locals.
#1 0x000000000052194e in read_msg (s=0x7f63e1f9d3b0, m=0x7f63e1f9d5a0)

at /root/src/dpdk/lib/librte_eal/common/eal_common_proc.c:258
         msglen = <optimized out>
         control =
"\000\000\000\000\000\000\000\000\336~\f\343c\177\000\000\005", '\000'
<repeats 23 times>, "\360\371\033\342c\177\000"
         cmsg = <optimized out>
         iov = {iov_base = 0x7f63e1f9d5a0, iov_len = 332}
       msgh = {msg_name = 0x7f63e1f9d3b0, msg_namelen = 110, msg_iov =
0x7f63e1f9d370, msg_iovlen = 1, msg_control = 0x7f63e1f9d380,
msg_controllen = 48, msg_flags = 0}
#2  mp_handle (arg=<optimized out>) at
/root/src/dpdk/lib/librte_eal/common/eal_common_proc.c:346
         msg = {type = 0, msg = {name = '\000' <repeats 63 times>,
len_param = 0, num_fds = 0, param = '\000' <repeats 20 times>, "\002",
'\000' <repeats 234 times>, fds = {0, 0, 0, 0, 0, 0, 0, 0}}}
         sa = {sun_family = 55104,
           sun_path =
"\371\341c\177\000\000\352\372\f\343c\177\000\000\000\000\000\000\000\000\000\000\377\377\377\377\377\377\377\377\000\367\371\341c\177\000\000\030\000\000\000\000\000\000\000p\327\371\341c\177\000\000\000\367\371\341c\177\000\000\000\367\371\341c\177",

'\000' <repeats 34 times>, "\200\037\000\000\377\377"}
#3  0x00007f63e258add5 in start_thread (arg=0x7f63e1f9f700) at
pthread_create.c:308
         __res = <optimized out>
         pd = 0x7f63e1f9f700
         now = <optimized out>
         unwind_buf = {cancel_jmp_buf = {{jmp_buf = {140066969745152,
1212869169857371576, 0, 8392704, 0, 140066969745152,
-1291625004586295880, -1291619793368703560}, mask_was_saved = 0}}, priv

= {pad = {0x0, 0x0, 0x0, 0x0}, data = {
               prev = 0x0, cleanup = 0x0, canceltype = 0}}}
         not_first_call = <optimized out>
         pagesize_m1 = <optimized out>
         sp = <optimized out>
         freesize = <optimized out>
#4  0x00007f63e22b4b3d in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:113
No locals.

I don't have more info for now.


Thanks for the feedback on this issue. I don't see obvious reason for this deadlock yet.

I'll investigate it asap (not tomorrow, but wednesday). In the worst case, we can revert the series if I cannot find the root cause rapidly.

I might think that the suggestion from Stephen of destroying the barrier can help this issue. I'll try to reproduce it and test it before sending a patch to fix it.

In case you don't reproduce, feel free to send me the patch to test it.

Below patch can fix another strange sigsegv issue in my VM. Please check if it works for you. I doubt it's use-after-free problem which could lead to different issues in different env. Please have a try.


diff --git a/lib/librte_eal/common/eal_common_thread.c b/lib/librte_eal/common/eal_common_thread.c
index de69452..d91b67d 100644
--- a/lib/librte_eal/common/eal_common_thread.c
+++ b/lib/librte_eal/common/eal_common_thread.c
@@ -205,6 +205,7 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
                goto fail;

        pthread_barrier_wait(&params->configured);
+       pthread_barrier_destroy(&params->configured);
        free(params);

        return 0;

Thanks,
Jianfeng


Thanks,
Maxime

Thanks,
Jianfeng


Olivier



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