[LTP] [PATCH] lib: Check minimal supported kernel version

[LTP] [PATCH] lib: Check minimal supported kernel version

[Andrea Cervesato]

From: Andrea Cervesato <andrea.cervesato@suse.com>

LTP does not support kernels older than 4.4, but this requirement was
only documented in static text without automated runtime validation.

Define the minimal supported kernel version in tst_kvercmp.h so that
the documentation fetches it dynamically and the core library aborts
unsupported kernels with TCONF during test setup.

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
Add a variable to check minimum kernel version before running tests.
Until now, the only place we have to verify the minimum kernel is to
read the documentation.
---
 doc/conf.py                     | 15 +++++++++++++++
 doc/users/supported_systems.rst |  2 +-
 include/tst_kvercmp.h           |  7 ++++++-
 lib/tst_test.c                  | 17 +++++++++++++++++
 4 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/doc/conf.py b/doc/conf.py
index c28db7af1..69ea31b0c 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -21,6 +21,21 @@ ltp_repo = 'https://github.com/linux-test-project/ltp'
 ltp_repo_base_url = f"{ltp_repo}/tree/master"
 cve_url = "https://www.cve.org/CVERecord?id="
 
+def _get_min_kernel_version():
+    header_path = os.path.join(os.path.dirname(__file__), '../include/tst_kvercmp.h')
+    with open(header_path, 'r', encoding='utf-8') as f:
+        match = re.search(r'#define\s+TST_MIN_KVER\s+"([^"]+)"', f.read())
+        if match:
+            return match.group(1)
+    raise RuntimeError(f"Could not find TST_MIN_KVER in {header_path}")
+
+min_kernel_version = _get_min_kernel_version()
+
+rst_prolog = f"""
+.. |min_kernel_version| replace:: **{min_kernel_version}**
+.. |min_kernel_version_plain| replace:: {min_kernel_version}
+"""
+
 # -- General configuration ---------------------------------------------------
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
 
diff --git a/doc/users/supported_systems.rst b/doc/users/supported_systems.rst
index b5d792eeb..5765214b0 100644
--- a/doc/users/supported_systems.rst
+++ b/doc/users/supported_systems.rst
@@ -14,7 +14,7 @@ branch is build tested in
 Kernel version
 --------------
 
-Minimal supported kernel version is **4.4**.
+Minimal supported kernel version is |min_kernel_version|.
 
 Oldest build tested distributions
 ---------------------------------
diff --git a/include/tst_kvercmp.h b/include/tst_kvercmp.h
index 26e8f8e3c..52267fd2b 100644
--- a/include/tst_kvercmp.h
+++ b/include/tst_kvercmp.h
@@ -1,12 +1,17 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later
  * Copyright (c) 2000 Silicon Graphics, Inc.  All Rights Reserved.
  * Copyright (c) 2009-2016 Cyril Hrubis chrubis@suse.cz
- * Copyright (c) Linux Test Project, 2020-2025
+ * Copyright (c) Linux Test Project, 2020-2026
  */
 
 #ifndef TST_KVERCMP_H__
 #define TST_KVERCMP_H__
 
+/**
+ * TST_MIN_KVER - Minimal kernel version supported by LTP.
+ */
+#define TST_MIN_KVER "4.4"
+
 /**
  * tst_kvcmp() - Compare given kernel version with kernel in string.
  *
diff --git a/lib/tst_test.c b/lib/tst_test.c
index 166e0f672..1bd62e24a 100644
--- a/lib/tst_test.c
+++ b/lib/tst_test.c
@@ -1087,6 +1087,21 @@ static bool check_kver(const char *min_kver, const int brk_nosupp)
 	return true;
 }
 
+static void check_supported_kver(void)
+{
+	int v1, v2, v3;
+
+	if (tst_parse_kver(TST_MIN_KVER, &v1, &v2, &v3)) {
+		tst_res(TWARN,
+			"Invalid minimal kernel version %s, expected %%d.%%d.%%d",
+			TST_MIN_KVER);
+		return;
+	}
+
+	if (tst_kvercmp(v1, v2, v3) < 0)
+		tst_brk(TCONF, "Kernel is older than minimal supported %s", TST_MIN_KVER);
+}
+
 /*
  * Checks if the struct results values are equal.
  *
@@ -1455,6 +1470,8 @@ static void do_setup(int argc, char *argv[])
 	if (context->tdebug)
 		tst_res(TINFO, "Enabling debug info (level %d)", context->tdebug);
 
+	check_supported_kver();
+
 	if (tst_test->needs_kconfigs && tst_kconfig_check(tst_test->needs_kconfigs))
 		tst_brk(TCONF, "Aborting due to unsuitable kernel config, see above!");
 

---
base-commit: d377d1cff1ec393459a136eec85088ffd5729430
change-id: 20260904-min_kernel-22066a2e046c

Best regards,
--  
Andrea Cervesato <andrea.cervesato@suse.com>


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Re: [LTP] lib: Check minimal supported kernel version

[linuxtestproject.agent]

Hi Andrea,

On September 4, 2026, Andrea Cervesato wrote:
> lib: Check minimal supported kernel version

Verdict - Reviewed

---
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] lib: Check minimal supported kernel version

[Cyril Hrubis]

Hi!
> LTP does not support kernels older than 4.4, but this requirement was
> only documented in static text without automated runtime validation.
> 
> Define the minimal supported kernel version in tst_kvercmp.h so that
> the documentation fetches it dynamically and the core library aborts
> unsupported kernels with TCONF during test setup.

Great idea, but I wouldn't tst_brk() on older kernels, I would just
print a message that there may be failures becuase older kernels are not
supported or tested.

LTP has been historically used for many different purposes, e.g. for
testing BSD compatibility layout for running Linux binaries and I fear
that hard stop on older kernel versions would break these usecases.

-- 
Cyril Hrubis
chrubis@suse.cz

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Re: [LTP] [PATCH] lib: Check minimal supported kernel version

[Andrea Cervesato via ltp]

Hi Cyril,

> Hi!
> > LTP does not support kernels older than 4.4, but this requirement was
> > only documented in static text without automated runtime validation.
> > 
> > Define the minimal supported kernel version in tst_kvercmp.h so that
> > the documentation fetches it dynamically and the core library aborts
> > unsupported kernels with TCONF during test setup.
> 
> Great idea, but I wouldn't tst_brk() on older kernels, I would just
> print a message that there may be failures becuase older kernels are not
> supported or tested.
> 
> LTP has been historically used for many different purposes, e.g. for
> testing BSD compatibility layout for running Linux binaries and I fear
> that hard stop on older kernel versions would break these usecases.

makes sense, I will send v2.

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

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Re: [LTP] [PATCH] lib: Check minimal supported kernel version

[Petr Vorel]

> Hi!
> > LTP does not support kernels older than 4.4, but this requirement was
> > only documented in static text without automated runtime validation.

> > Define the minimal supported kernel version in tst_kvercmp.h so that
> > the documentation fetches it dynamically and the core library aborts
> > unsupported kernels with TCONF during test setup.

> Great idea, but I wouldn't tst_brk() on older kernels, I would just
> print a message that there may be failures becuase older kernels are not
> supported or tested.

Yes, exactly, tst_brk() is way too aggressive. tst_res(TINFO) is good enough
to give the information without deliberately break all the tests.

> LTP has been historically used for many different purposes, e.g. for
> testing BSD compatibility layout for running Linux binaries and I fear
> that hard stop on older kernel versions would break these usecases.

+1.

Kind regards,
Petr

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Re: [LTP] lib: Check minimal supported kernel version

[linuxtestproject.agent]

Hi Andrea,

On Fri, 4 Sep 2026, Andrea Cervesato wrote:
> lib: Check minimal supported kernel version

> +	if (tst_kvercmp(v1, v2, v3) < 0)
> +		tst_brk(TWARN, "Kernel is older than minimal supported %s", TST_MIN_KVER);

This exits with TWARN, contrary to the commit message's stated TCONF
behavior. Use tst_brk(TCONF, ...) so unsupported kernels are reported as
skipped configurations.

Verdict - Needs revision

---
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] lib: Check minimal supported kernel version

[Andrea Cervesato via ltp]

> This exits with TWARN, contrary to the commit message's stated TCONF
> behavior. Use tst_brk(TCONF, ...) so unsupported kernels are reported as
> skipped configurations.

@Petr @Cyril @Li This can be fixed before merge if you agree with it.

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

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Re: [LTP] [PATCH] lib: Check minimal supported kernel version

[Kubaj, Piotr]

W dniu pią, 04.09.2026 o godzinie 11∶20 +0200, użytkownik Cyril Hrubis
napisał:
> Hi!
> > LTP does not support kernels older than 4.4, but this requirement
> > was
> > only documented in static text without automated runtime
> > validation.
> > 
> > Define the minimal supported kernel version in tst_kvercmp.h so
> > that
> > the documentation fetches it dynamically and the core library
> > aborts
> > unsupported kernels with TCONF during test setup.
> 
> Great idea, but I wouldn't tst_brk() on older kernels, I would just
> print a message that there may be failures becuase older kernels are
> not
> supported or tested.
> 
> LTP has been historically used for many different purposes, e.g. for
> testing BSD compatibility layout for running Linux binaries and I
> fear
> that hard stop on older kernel versions would break these usecases.
> 
> -- 
> Cyril Hrubis
> chrubis@suse.cz
Hi,

speaking with my pkubaj@FreeBSD.org hat on, see
https://cgit.freebsd.org/src/tree/sys/compat/linux/linux_mib.h

The current claimed compatibility level is Linux 5.15.0. Even if you
look at
https://cgit.freebsd.org/src/tree/sys/compat/linux/linux_mib.h?h=releng%2F14.4
(which is the oldest still-supported version), it's also 5.15.0.

I think NetBSD also has a Linux compatibility layer, but I'm not sure
how up-to-date it is.
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