Re: [LTP] [PATCH v2] waitid10: Set the core dump file location to temporary directory

[Mina Chou via ltp <ltp@lists.linux.it>]

On Wed, Apr 03, 2024 at 12:59:37PM +0200, Cyril Hrubis wrote:
> [EXTERNAL MAIL]
> 
> Hi!
> > When testing via NFS mount LTP folder on the board, with the NFS server
> > configured using 'anonuid' and 'anongid' options to set specific
> > uid/gid, waitid10 fails. This is due to a uid mismatch during core dump
> > file creation, leading to an aborted dump, resulting in the child
> > process receiving the signal CLD_KILLED instead of CLD_DUMPED.
> >
> >   # ./waitid10
> >   tst_buffers.c:56: TINFO: Test is using guarded buffers
> >   tst_test.c:1732: TINFO: LTP version: 20240129
> >   tst_test.c:1616: TINFO: Timeout per run is 0h 05m 00s
> >   waitid10.c:64: TINFO: Raising RLIMIT_CORE rlim_cur=0 -> 0
> >   [  296.482665] mnt_uid= 1036, curr_uid= 0
> >   [  296.483041] Core dump to core aborted: cannot preserve file owner
> >   waitid10.c:36: TPASS: waitid(P_ALL, 0, infop, WEXITED) passed
> >   waitid10.c:37: TPASS: infop->si_pid == pidchild (149)
> >   waitid10.c:38: TPASS: infop->si_status == SIGFPE (8)
> >   waitid10.c:39: TPASS: infop->si_signo == SIGCHLD (17)
> >   waitid10.c:42: TFAIL: infop->si_code (2) != CLD_DUMPED (3)
> >
> > Therefore, referring to madvise08, during testing, set the core dump file
> > to the temporary directory instead of the current working directory. After
> > testing, restore the contents of /proc/sys/kernel/core_pattern and clear
> > all test temporary file.
> 
> Thanks for the detailed description, now it's clear what happens on your
> system.
> 
> >   # ./waitid10
> >   tst_buffers.c:56: TINFO: Test is using guarded buffers
> >   tst_test.c:1709: TINFO: LTP version: 20240129-45-g69537563d16a
> >   tst_test.c:1593: TINFO: Timeout per run is 0h 05m 00s
> >   waitid10.c:60: TINFO: Temporary core pattern is '/tmp/LTP_waiSzyEv2/core'
> >   waitid10.c:73: TINFO: Raising RLIMIT_CORE rlim_cur=0 -> 0
> >   [68549.534126] mnt_uid= 0, curr_uid= 0
> >   waitid10.c:38: TPASS: waitid(P_ALL, 0, infop, WEXITED) passed
> >   waitid10.c:39: TPASS: infop->si_pid == pidchild (163)
> >   waitid10.c:40: TPASS: infop->si_status == SIGFPE (8)
> >   waitid10.c:41: TPASS: infop->si_signo == SIGCHLD (17)
> >   waitid10.c:44: TPASS: infop->si_code == CLD_DUMPED (3)
> >
> > Signed-off-by: Hui Min Mina Chou <minachou@andestech.com>
> > ---
> >  testcases/kernel/syscalls/waitid/waitid10.c | 16 +++++++++++++++-
> >  1 file changed, 15 insertions(+), 1 deletion(-)
> >
> > diff --git a/testcases/kernel/syscalls/waitid/waitid10.c b/testcases/kernel/syscalls/waitid/waitid10.c
> > index e55e88c2325e..3e48f52d0ea8 100644
> > --- a/testcases/kernel/syscalls/waitid/waitid10.c
> > +++ b/testcases/kernel/syscalls/waitid/waitid10.c
> > @@ -16,6 +16,8 @@
> >  #include <sys/prctl.h>
> >  #include "tst_test.h"
> >
> > +#define CORE_PATTERN "/proc/sys/kernel/core_pattern"
> > +
> >  static siginfo_t *infop;
> >  static int core_dumps = 1;
> >
> > @@ -48,9 +50,16 @@ static void setup(void)
> >  {
> >       struct rlimit rlim;
> >       char c;
> > +     char cwd[1024];
> > +     char tmpcpattern[1048];
> >
> >       SAFE_GETRLIMIT(RLIMIT_CORE, &rlim);
> > -     SAFE_FILE_SCANF("/proc/sys/kernel/core_pattern", "%c", &c);
> > +
> > +     SAFE_GETCWD(cwd, sizeof(cwd));
> > +     snprintf(tmpcpattern, sizeof(tmpcpattern), "%s/core", cwd);
> > +     tst_res(TINFO, "Temporary core pattern is '%s'", tmpcpattern);
> > +     SAFE_FILE_PRINTF(CORE_PATTERN, "%s", tmpcpattern);
> > +     SAFE_FILE_SCANF(CORE_PATTERN, "%c", &c);
> 
> Given the description do we really need to change the core pattern?
> 
> I guess that just adding .needs_tmpdir = 1 would fix the test since the
> test $CWD would point to the test temporary directory.
>

Yes, you're right! Simply adding .needs_tmpdir = 1 can solve the issue.
Thanks, I'll revise another version.

> >       if (rlim.rlim_cur)
> >               return;
> > @@ -76,4 +85,9 @@ static struct tst_test test = {
> >               {&infop, .size = sizeof(*infop)},
> >               {},
> >       },
> > +     .needs_tmpdir = 1,
> > +     .save_restore = (const struct tst_path_val[]) {
> > +             {CORE_PATTERN, NULL, TST_SR_TCONF},
> > +             {}
> > +     },
> >  };
> > --
> > 2.34.1
> >
> >
> > --
> > Mailing list info: https://lists.linux.it/listinfo/ltp
> 
> --
> Cyril Hrubis
> chrubis@suse.cz

Thanks,
Mina

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