[LTP] [PATCH] syscall: set FORK in tst_sig for some old tests

[LTP] [PATCH] syscall: set FORK in tst_sig for some old tests

[Li Wang]

From: Li Wang <liwang@hygon.cn>

Since commit d90d2004657b ("lib: Use backoff polling to wait for loop
device nodes") use TST_RETRY_FN_EXP_BACKOFF(), which calls tst_multiply_timeout().
That in turn reaches tst_has_slow_kconfig() -> tst_kconfig_read() ->
popen("zcat /proc/config.gz") to read the kernel config.

popen() forks a child, and that child exits the SIGCHLD is reported
as an unexpected signal by the tst_sig(NOFORK) handler:

  umount2_01    1  TBROK  :  tst_sig.c:232: unexpected signal SIGCHLD(17) received

Since these tests now genuinely fork (indirectly via popen), declaring
FORK matches their actual behavior and lets the handler tolerate the
child's SIGCHLD. This is a minimal fix that preserves the retry logic.

These are old-API tests that will eventually be converted to the new
tst_test API and this issue disappears entirely. The one-line FORK
change is a low-cost bridge until then.

Fixes: d90d2004657b ("lib: Use backoff polling to wait for loop device nodes")
Signed-off-by: Li Wang <liwang@hygon.cn>
---

Notes:
    This is a temporary solution for the regression, I will convert
    these old tests to the new API next few days.

 testcases/kernel/syscalls/linkat/linkat02.c     | 2 +-
 testcases/kernel/syscalls/mknodat/mknodat02.c   | 2 +-
 testcases/kernel/syscalls/rename/rename11.c     | 2 +-
 testcases/kernel/syscalls/renameat/renameat01.c | 2 +-
 testcases/kernel/syscalls/umount2/umount2_01.c  | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/testcases/kernel/syscalls/linkat/linkat02.c b/testcases/kernel/syscalls/linkat/linkat02.c
index 273587271..6dfa7cfb5 100644
--- a/testcases/kernel/syscalls/linkat/linkat02.c
+++ b/testcases/kernel/syscalls/linkat/linkat02.c
@@ -140,7 +140,7 @@ static void setup(void)
 {
 	tst_require_root();
 
-	tst_sig(NOFORK, DEF_HANDLER, cleanup);
+	tst_sig(FORK, DEF_HANDLER, cleanup);
 
 	tst_tmpdir();
 
diff --git a/testcases/kernel/syscalls/mknodat/mknodat02.c b/testcases/kernel/syscalls/mknodat/mknodat02.c
index 2f7c56f00..89cfc5978 100644
--- a/testcases/kernel/syscalls/mknodat/mknodat02.c
+++ b/testcases/kernel/syscalls/mknodat/mknodat02.c
@@ -107,7 +107,7 @@ static void setup(void)
 
 	tst_require_root();
 
-	tst_sig(NOFORK, DEF_HANDLER, cleanup);
+	tst_sig(FORK, DEF_HANDLER, cleanup);
 
 	tst_tmpdir();
 
diff --git a/testcases/kernel/syscalls/rename/rename11.c b/testcases/kernel/syscalls/rename/rename11.c
index 8ff9f7d38..26e324d64 100644
--- a/testcases/kernel/syscalls/rename/rename11.c
+++ b/testcases/kernel/syscalls/rename/rename11.c
@@ -90,7 +90,7 @@ static void setup(void)
 {
 	int i;
 
-	tst_sig(NOFORK, DEF_HANDLER, cleanup);
+	tst_sig(FORK, DEF_HANDLER, cleanup);
 
 	tst_require_root();
 
diff --git a/testcases/kernel/syscalls/renameat/renameat01.c b/testcases/kernel/syscalls/renameat/renameat01.c
index 72e72b481..f9ed3a9a7 100644
--- a/testcases/kernel/syscalls/renameat/renameat01.c
+++ b/testcases/kernel/syscalls/renameat/renameat01.c
@@ -134,7 +134,7 @@ static void setup(void)
 
 	tst_require_root();
 
-	tst_sig(NOFORK, DEF_HANDLER, cleanup);
+	tst_sig(FORK, DEF_HANDLER, cleanup);
 
 	tst_tmpdir();
 
diff --git a/testcases/kernel/syscalls/umount2/umount2_01.c b/testcases/kernel/syscalls/umount2/umount2_01.c
index 274409ef3..c6496e306 100644
--- a/testcases/kernel/syscalls/umount2/umount2_01.c
+++ b/testcases/kernel/syscalls/umount2/umount2_01.c
@@ -67,7 +67,7 @@ static void setup(void)
 {
 	tst_require_root();
 
-	tst_sig(NOFORK, DEF_HANDLER, NULL);
+	tst_sig(FORK, DEF_HANDLER, NULL);
 
 	tst_tmpdir();
 
-- 
2.55.0


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Re: [LTP] syscall: set FORK in tst_sig for some old tests

[linuxtestproject.agent]

Hi Li,

On Aug 13, 2026, Li Wang wrote:
> syscall: set FORK in tst_sig for some old tests

Verdict - Reviewed

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Note:

The agent can sometimes produce false positives although often its
findings are genuine. If you find issues with the review, please
comment this email or ignore the suggestions.

Regards,
LTP AI Reviewer

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Re: [LTP] [PATCH] syscall: set FORK in tst_sig for some old tests

[Avinesh Kumar via ltp]

Hi Li,

Thank you for addressing this.
Reviewed-by: Avinesh Kumar <avinesh.kumar@suse.com>

Petr,
I think we should use this solution instead of reverting the patch.


Regards,
Avinesh

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Re: [LTP] [PATCH] syscall: set FORK in tst_sig for some old tests

[Wake Liu via ltp]

Hi Li, Petr, Avinesh,

Thanks Li for the quick analysis and for proposing this patch.
I agree that this approach is much better than reverting d90d2004657b.

Reviewed-by: Wake Liu <wakel@google.com>

Best regards,
Wake

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Re: [LTP] [PATCH] syscall: set FORK in tst_sig for some old tests

[Andrea Cervesato via ltp]

Reviewed-by: Andrea Cervesato <andrea.cervesato@suse.com>

--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com

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Re: [LTP] [PATCH] syscall: set FORK in tst_sig for some old tests

[Petr Vorel]

Hi all,

> Hi Li,

> Thank you for addressing this.

Li, thanks for fixing it!

Reviewed-by: Petr Vorel <pvorel@suse.cz>
Tested-by: Petr Vorel <pvorel@suse.cz>

> Reviewed-by: Avinesh Kumar <avinesh.kumar@suse.com>

> Petr,
> I think we should use this solution instead of reverting the patch.

+1, thanks for a notification

Kind regards,
Petr

> Regards,
> Avinesh

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Re: [LTP] [PATCH] syscall: set FORK in tst_sig for some old tests

[Li Wang]

Hi Petr, All,

> Reviewed-by: Petr Vorel <pvorel@suse.cz>
> Tested-by: Petr Vorel <pvorel@suse.cz>

Patch merged! Thanks~

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Regards,
Li Wang

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Re: [LTP] [PATCH] syscall: set FORK in tst_sig for some old tests

[Petr Vorel]

Hi Li,

> Hi Petr, All,

> > Reviewed-by: Petr Vorel <pvorel@suse.cz>
> > Tested-by: Petr Vorel <pvorel@suse.cz>

> Patch merged! Thanks~

Thanks for fixing it!

very nit: there could have been
Reported-by: Avinesh Kumar <avinesh.kumar@suse.com>

Kind regards,
Petr

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Re: [LTP] [PATCH] syscall: set FORK in tst_sig for some old tests

[Li Wang]

Hi Avinesh, Petr,

> > Patch merged! Thanks~
> 
> Thanks for fixing it!

> very nit: there could have been
> Reported-by: Avinesh Kumar <avinesh.kumar@suse.com>

That's true, apologies for my carelessness.

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Regards,
Li Wang

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