[LTP] Suggested fix for the mremap03 syscall testcase

[LTP] Suggested fix for the mremap03 syscall testcase

[Martin Cermak via ltp]

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Hello folks,

I suspect that LTP commit 88cfde5fbc14b23f673b81855127448a519679c0
introduced a regression it the mremap03 testcase.  I've originally
reported it as a Valgrind bug:

https://bugs.kde.org/show_bug.cgi?id=526974

But now I think it's an LTP bug.  Proposed fix:

$ cat 0001-Fix-the-mremap03-syscall-testcase.patch
From 3ddcfa8c303feeb8681632e458d71001fbfb825c Mon Sep 17 00:00:00 2001
From: Martin Cermak <mcermak@redhat.com>
Date: Wed, 14 Oct 2026 14:07:45 +0200
Subject: [PATCH] Fix the mremap03 syscall testcase

Commit 88cfde5fbc14b23f673b81855127448a519679c0 introduced a regression
in the setup() function of the mremap03 testcase.  The goal is to pass
a bad_addr to the mremap() syscall.

The original version of the setup() function did generate the bad_addr
using tst_get_bad_addr().  This gives a mapped address which is not
accessible (PROT_NONE).  The new version of the test does the same, but
unmaps that address right after that.  Valgrind flags that as an error.

This patch restores the original behavior of the setup() funcrion.
---
 testcases/kernel/syscalls/mremap/mremap03.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/testcases/kernel/syscalls/mremap/mremap03.c b/testcases/kernel/syscalls/mremap/mremap03.c
index 4e647cdca..6003657d4 100644
--- a/testcases/kernel/syscalls/mremap/mremap03.c
+++ b/testcases/kernel/syscalls/mremap/mremap03.c
@@ -35,7 +35,6 @@ static void setup(void)
 	newsize = 2 * memsize;

 	bad_addr = tst_get_bad_addr(NULL);
-	SAFE_MUNMAP(bad_addr, page_size);
 }

 static void run(void)
--
2.55.0

$

Thanks,
Martin

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From 3ddcfa8c303feeb8681632e458d71001fbfb825c Mon Sep 17 00:00:00 2001
From: Martin Cermak <mcermak@redhat.com>
Date: Wed, 14 Oct 2026 14:07:45 +0200
Subject: [PATCH] Fix the mremap03 syscall testcase

Commit 88cfde5fbc14b23f673b81855127448a519679c0 introduced a regression
in the setup() function of the mremap03 testcase.  The goal is to pass
a bad_addr to the mremap() syscall.

The original version of the setup() function did generate the bad_addr
using tst_get_bad_addr().  This gives a mapped address which is not
accessible (PROT_NONE).  The new version of the test does the same, but
unmaps that address right after that.  Valgrind flags that as an error.

This patch restores the original behavior of the setup() funcrion.
---
 testcases/kernel/syscalls/mremap/mremap03.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/testcases/kernel/syscalls/mremap/mremap03.c b/testcases/kernel/syscalls/mremap/mremap03.c
index 4e647cdca..6003657d4 100644
--- a/testcases/kernel/syscalls/mremap/mremap03.c
+++ b/testcases/kernel/syscalls/mremap/mremap03.c
@@ -35,7 +35,6 @@ static void setup(void)
 	newsize = 2 * memsize;
 
 	bad_addr = tst_get_bad_addr(NULL);
-	SAFE_MUNMAP(bad_addr, page_size);
 }
 
 static void run(void)
-- 
2.55.0


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Re: [LTP] Fix the mremap03 syscall testcase

[linuxtestproject.agent]

Hi Martin,

On Wed, 14 Oct 2026, Martin Cermak wrote:
> Fix the mremap03 syscall testcase

> diff --git a/testcases/kernel/syscalls/mremap/mremap03.c b/testcases/kernel/syscalls/mremap/mremap03.c
> @@ -35,7 +35,6 @@ static void setup(void)
>  	bad_addr = tst_get_bad_addr(NULL);
> -	SAFE_MUNMAP(bad_addr, page_size);

tst_get_bad_addr() returns a mapped PROT_NONE page, which mremap() can
resize; deleting this line drops the documented unmapped-old_address case.
The test still passes because old_size is 1000 pages and extends beyond
that VMA, exercising a different EFAULT check. Keep SAFE_MUNMAP() here to
preserve coverage of an unmapped old_address.

> This patch restores the original behavior of the setup() funcrion.

The commit message is missing the required Signed-off-by: trailer.
Add it at the end of the message.

Verdict - Needs revision

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Regards,
LTP AI Reviewer

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Re: [LTP] Suggested fix for the mremap03 syscall testcase

[Andrea Cervesato via ltp]

Hi Martin,

you are right. That’s a bug we didn’t spot during the test rewrite. Thanks.

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

> On 14. Oct 2026, at 14:20, Martin Cermak via ltp <ltp@lists.linux.it> wrote:
> 
> Hello folks,
> 
> I suspect that LTP commit 88cfde5fbc14b23f673b81855127448a519679c0
> introduced a regression it the mremap03 testcase.  I've originally
> reported it as a Valgrind bug:
> 
> https://bugs.kde.org/show_bug.cgi?id=526974
> 
> But now I think it's an LTP bug.  Proposed fix:
> 
> $ cat 0001-Fix-the-mremap03-syscall-testcase.patch
> From 3ddcfa8c303feeb8681632e458d71001fbfb825c Mon Sep 17 00:00:00 2001
> From: Martin Cermak <mcermak@redhat.com>
> Date: Wed, 14 Oct 2026 14:07:45 +0200
> Subject: [PATCH] Fix the mremap03 syscall testcase
> 
> Commit 88cfde5fbc14b23f673b81855127448a519679c0 introduced a regression
> in the setup() function of the mremap03 testcase.  The goal is to pass
> a bad_addr to the mremap() syscall.
> 
> The original version of the setup() function did generate the bad_addr
> using tst_get_bad_addr().  This gives a mapped address which is not
> accessible (PROT_NONE).  The new version of the test does the same, but
> unmaps that address right after that.  Valgrind flags that as an error.
> 
> This patch restores the original behavior of the setup() funcrion.
> ---
> testcases/kernel/syscalls/mremap/mremap03.c | 1 -
> 1 file changed, 1 deletion(-)
> 
> diff --git a/testcases/kernel/syscalls/mremap/mremap03.c b/testcases/kernel/syscalls/mremap/mremap03.c
> index 4e647cdca..6003657d4 100644
> --- a/testcases/kernel/syscalls/mremap/mremap03.c
> +++ b/testcases/kernel/syscalls/mremap/mremap03.c
> @@ -35,7 +35,6 @@ static void setup(void)
>    newsize = 2 * memsize;
> 
>    bad_addr = tst_get_bad_addr(NULL);
> -    SAFE_MUNMAP(bad_addr, page_size);
> }
> 
> static void run(void)
> --
> 2.55.0
> 
> $
> 
> Thanks,
> Martin
> <0001-Fix-the-mremap03-syscall-testcase.patch>
> 
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> Mailing list info: https://lists.linux.it/listinfo/ltp

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