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

[Martin Cermak via ltp <ltp@lists.linux.it>]

Hi Petr,

with patched testcase, valgrind doesn't crash any more, at least
my fresh upstream version of valgrind doesn't:

$ git log -1 --oneline testcases/kernel/syscalls/mremap/mremap03.c
3ddcfa8c3 (HEAD -> master) Fix the mremap03 syscall testcase
$ valgrind --version
valgrind-3.28.0.GIT
$ valgrind testcases/kernel/syscalls/mremap/mremap03
==1419973== Memcheck, a memory error detector
==1419973== Copyright (C) 2002-2026, and GNU GPL'd, by Julian Seward et al.
==1419973== Using Valgrind-3.28.0.GIT and LibVEX; rerun with -h for copyright info
==1419973== Command: testcases/kernel/syscalls/mremap/mremap03
==1419973== 
tst_test.c:2061: TINFO: LTP version: 20260930-20-g3ddcfa8c3
tst_test.c:2064: TINFO: Tested kernel: 7.2.7-200.fc44.x86_64 #1 SMP PREEMPT_DYNAMIC Mon Sep 21 18:25:57 UTC 2026 x86_64
tst_kconfig.c:73: TINFO: Couldn't locate kernel config!
tst_test.c:1895: TINFO: Overall timeout per run is 0h 00m 30s
mremap03.c:42: TFAIL: mremap(bad_addr, memsize, newsize, MREMAP_MAYMOVE) expected EFAULT: EINVAL (22)
==1419992== 
==1419992== HEAP SUMMARY:
==1419992==     in use at exit: 0 bytes in 0 blocks
==1419992==   total heap usage: 13 allocs, 13 frees, 7,647 bytes allocated
==1419992== 
==1419992== All heap blocks were freed -- no leaks are possible
==1419992== 
==1419992== For lists of detected and suppressed errors, rerun with: -s
==1419992== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

Summary:
passed   0
failed   1
broken   0
skipped  0
warnings 0
==1419973== 
==1419973== HEAP SUMMARY:
==1419973==     in use at exit: 0 bytes in 0 blocks
==1419973==   total heap usage: 6 allocs, 6 frees, 4,488 bytes allocated
==1419973== 
==1419973== All heap blocks were freed -- no leaks are possible
==1419973== 
==1419973== For lists of detected and suppressed errors, rerun with: -s
==1419973== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
$

But that doesn't mean things are perfect.  The main problem is
that under valgrind the testcase behaves differently compared to
a run without valgrind. Looking into it.  Thanks for the merge.

Martin

On  Thu  2026-10-15  10:38 , Petr Vorel wrote:
> Hi Martin, Andrea, 
> 
> > Hi Martin,
> 
> > you are right. That’s a bug we didn’t spot during the test rewrite. Thanks.
> 
> Good catch, Martin, you're of course right => turned into proper patch and
> merged.
> 
> valgrind ./mremap03
> tst_test.c:1895: TINFO: Overall timeout per run is 0h 00m 30s
> --292799-- VALGRIND INTERNAL ERROR: Valgrind received a signal 11 (SIGSEGV) - exiting
> --292799-- si_code=1;  Faulting address: 0x8;  sp: 0x1002ef2cc0
> 
> valgrind: the 'impossible' happened:
>    Killed by fatal signal
> 
> host stacktrace:
> ==292799==    at 0x580AE3D3: ??? (in /usr/libexec/valgrind/memcheck-amd64-linux)
> ==292799==    by 0x580A7ED9: ??? (in /usr/libexec/valgrind/memcheck-amd64-linux)
> ==292799==    by 0x580A387A: ??? (in /usr/libexec/valgrind/memcheck-amd64-linux)
> ==292799==    by 0x580A58A6: ??? (in /usr/libexec/valgrind/memcheck-amd64-linux)
> ==292799==    by 0x58115088: ??? (in /usr/libexec/valgrind/memcheck-amd64-linux)
> 
> BTW testcase after fix still fails, but that's I suppose just expected valgrind
> behavior on mmap(PROT_NONE), right?
> 
> valgrind ./mremap03
> ==292941== Memcheck, a memory error detector
> ==292941== Copyright (C) 2002-2026, and GNU GPL'd, by Julian Seward et al.
> ==292941== Using Valgrind-3.27.1 and LibVEX; rerun with -h for copyright info
> ==292941== Command: ./mremap03
> ==292941==
> tst_test.c:2061: TINFO: LTP version: 20260930-20-gd494a8e1c9
> ...
> tst_test.c:1895: TINFO: Overall timeout per run is 0h 00m 30s
> mremap03.c:42: TFAIL: mremap(bad_addr, memsize, newsize, MREMAP_MAYMOVE) expected EFAULT: EINVAL (22)
> 
> Kind regards,
> Petr
> 
> 


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