Re: [BUG] selftests/nci: ./nci_dev hang in wait4()

[Mirsad Todorovac]

On 9/20/24 18:22, Mirsad Todorovac wrote:
> Hi, all,
> 
> I was testing Linux torvalds tree vanilla kernel, and I've noticed for a number of releases this
> ./nci_dev stops testing until it's terminated (15).
> 
> Now, I tried to examine what went wrong, I hoped it will go away by itself. it didn't, so I am posting
> a bug report.
> 
> The ./nci_dev seems to be stuck in several processes waiting on each other. I was able to produce
> stacktraces. I am unable to tell if it is testsuite bug or a problem in underlying syscalls.
> 
> user@host:~/linux/kernel/linux_torvalds$ sudo gdb --pid 14132
> GNU gdb (Ubuntu 15.0.50.20240403-0ubuntu1) 15.0.50.20240403-git
> Copyright (C) 2024 Free Software Foundation, Inc.
> License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
> This is free software: you are free to change and redistribute it.
> There is NO WARRANTY, to the extent permitted by law.
> Type "show copying" and "show warranty" for details.
> This GDB was configured as "x86_64-linux-gnu".
> Type "show configuration" for configuration details.
> For bug reporting instructions, please see:
> <https://www.gnu.org/software/gdb/bugs/>.
> Find the GDB manual and other documentation resources online at:
>     <http://www.gnu.org/software/gdb/documentation/>.
> 
> For help, type "help".
> Type "apropos word" to search for commands related to "word".
> Attaching to process 14132
> Reading symbols from /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/nci/nci_dev...
> Reading symbols from /lib/x86_64-linux-gnu/libc.so.6...
> Reading symbols from /usr/lib/debug/.build-id/6d/64b17fbac799e68da7ebd9985ddf9b5cb375e6.debug...
> Reading symbols from /lib64/ld-linux-x86-64.so.2...
> Reading symbols from /usr/lib/debug/.build-id/35/3e1b6cb0eebc08cf3ff812eae8a51b4efd684e.debug...
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
> 0x00007be7cf3107a7 in __GI___wait4 (pid=pid@entry=14133, stat_loc=stat_loc@entry=0x7ffef60482dc, options=options@entry=0, usage=usage@entry=0x0) at ../sysdeps/unix/sysv/linux/wait4.c:30
> 
> warning: 30	../sysdeps/unix/sysv/linux/wait4.c: No such file or directory
> (gdb) where
> #0  0x00007be7cf3107a7 in __GI___wait4 (pid=pid@entry=14133, stat_loc=stat_loc@entry=0x7ffef60482dc, options=options@entry=0, usage=usage@entry=0x0) at ../sysdeps/unix/sysv/linux/wait4.c:30
> #1  0x00007be7cf3108eb in __GI___waitpid (pid=pid@entry=14133, stat_loc=stat_loc@entry=0x7ffef60482dc, options=options@entry=0) at ./posix/waitpid.c:38
> #2  0x00005d550d59299b in wrapper_NCI_start_poll (_metadata=0x7be7cf486000, variant=0x5d550d597020 <_NCI_NCI2_0_object>) at nci_dev.c:625
> #3  0x00005d550d591a94 in __run_test (f=f@entry=0x5d550d5970a0 <_NCI_fixture_object>, variant=variant@entry=0x5d550d597020 <_NCI_NCI2_0_object>, t=t@entry=0x7be7cf486000) at ../kselftest_harness.h:1249
> #4  0x00005d550d58fd47 in test_harness_run (argv=0x7ffef60488f8, argc=1) at ../kselftest_harness.h:1319
> #5  main (argc=1, argv=0x7ffef60488f8) at nci_dev.c:904
> (gdb) 
> 
> user@host:~$ sudo gdb --pid 14133
> GNU gdb (Ubuntu 15.0.50.20240403-0ubuntu1) 15.0.50.20240403-git
> Copyright (C) 2024 Free Software Foundation, Inc.
> License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
> This is free software: you are free to change and redistribute it.
> There is NO WARRANTY, to the extent permitted by law.
> Type "show copying" and "show warranty" for details.
> This GDB was configured as "x86_64-linux-gnu".
> Type "show configuration" for configuration details.
> For bug reporting instructions, please see:
> <https://www.gnu.org/software/gdb/bugs/>.
> Find the GDB manual and other documentation resources online at:
>     <http://www.gnu.org/software/gdb/documentation/>.
> 
> For help, type "help".
> Type "apropos word" to search for commands related to "word".
> Attaching to process 14133
> [New LWP 14137]
> [Thread debugging using libthread_db enabled]
> Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
> 0x00007be7cf298d61 in __futex_abstimed_wait_common64 (private=128, cancel=true, abstime=0x0, op=265, expected=14137, futex_word=0x7be7cf000990) at ./nptl/futex-internal.c:57
> 
> warning: 57	./nptl/futex-internal.c: No such file or directory
> (gdb) where
> #0  0x00007be7cf298d61 in __futex_abstimed_wait_common64 (private=128, cancel=true, abstime=0x0, op=265, expected=14137, futex_word=0x7be7cf000990) at ./nptl/futex-internal.c:57
> #1  __futex_abstimed_wait_common (cancel=true, private=128, abstime=0x0, clockid=0, expected=14137, futex_word=0x7be7cf000990) at ./nptl/futex-internal.c:87
> #2  __GI___futex_abstimed_wait_cancelable64 (futex_word=futex_word@entry=0x7be7cf000990, expected=14137, clockid=clockid@entry=0, abstime=abstime@entry=0x0, private=private@entry=128)
>     at ./nptl/futex-internal.c:139
> #3  0x00007be7cf29e793 in __pthread_clockjoin_ex (threadid=136235540547264, thread_return=thread_return@entry=0x7ffef6047dd0, clockid=clockid@entry=0, abstime=abstime@entry=0x0, 
>     block=block@entry=true) at ./nptl/pthread_join_common.c:102
> #4  0x00007be7cf29e633 in ___pthread_join (threadid=<optimized out>, thread_return=thread_return@entry=0x7ffef6047dd0) at ./nptl/pthread_join.c:24
> #5  0x00005d550d591e48 in NCI_setup (_metadata=_metadata@entry=0x7be7cf486000, self=self@entry=0x7ffef60482e0, variant=<optimized out>) at nci_dev.c:447
> #6  0x00005d550d5929f3 in wrapper_NCI_start_poll (_metadata=0x7be7cf486000, variant=0x5d550d597020 <_NCI_NCI2_0_object>) at nci_dev.c:625
> #7  0x00005d550d591a94 in __run_test (f=f@entry=0x5d550d5970a0 <_NCI_fixture_object>, variant=variant@entry=0x5d550d597020 <_NCI_NCI2_0_object>, t=t@entry=0x7be7cf486000)
>     at ../kselftest_harness.h:1249
> #8  0x00005d550d58fd47 in test_harness_run (argv=0x7ffef60488f8, argc=1) at ../kselftest_harness.h:1319
> #9  main (argc=1, argv=0x7ffef60488f8) at nci_dev.c:904
> (gdb) 
> 
> I hope this can help you see what went wrong. The testing suite gets stuck on each run.
> 
> Best regards,
> Mirsad Todorovac

P.S.

Forgot to mention, the kernel was 6.11.0 release.

Mea culpa.

Best regards,
Mirsad Todorovac