linux-toradex.git/tools/testing/selftests/clone3, branch master

selftests/clone3: fix wild pointer access of getline due to missing init

2026-07-29T00:37:33+00:00

Patch series "selftests: Add missing initalization of pointer passed to
getline", v2.


This patch (of 2):

Clone3_set_tid uses getline(&line, ...) in a loop to read the child's
process status.  The code expects that getline allocates the buffer for
the line on the first loop iteration.  According to the Open Group
Spec[1], char *line has to be null pointer for this:

> ssize_t getline(char **restrict lineptr, ...);
> If *lineptr is a null pointer or if the object pointed to by *lineptr
> is of insufficient size, an object shall be allocated as if by
malloc()
> or the object shall be reallocated as if by realloc()[...].

However, char *line is only declared, leading to an undefined value that
is potentially non-null.  In an example run with Musl v1.2.6, the realloc
call[2] of getdelim, which implements getline, triggers a segfault:

./run_kselftest.sh --test clone3:clone3_set_tid
[ 1366.165898] kselftest: Running tests in clone3
...
[ 1367.799244] clone3_set_tid[811]: unhandled signal 11 code 0x1 at
0x0000000000000000 in libc.so[68184,3fbf69f000+4c000]
[ 1367.802808] CPU: 0 UID: 0 PID: 811 Comm: clone3_set_tid Not tainted
..
[ 1367.804188]  epc: 0x0000003fbf6b0184
[ 1367.804188]  ra : 0x0000003fbf6d4664
[ 1367.804188]  sp : 0x0000003fce5f2e40
[ 1367.805314]  gp : 0x0000002aaab0dfb8
[ 1367.805314]  tp : 0x0000003fbf6f14a8
[ 1367.805314]  t0 : 0x0000003fbf63d000
...

Looking at the realloc implementation, Musl mallocs for a null pointer
memory.  But for a non-null pointer, it assumes it's passed a valid
pointer to the heap and tries to access its meta-data.  This leads to the
segfault we see:

void *realloc(void *p, size_t n)
{
        if (!p) return malloc(n);
        if (size_overflows(n)) return 0;

        struct meta *g = get_meta(p);
        ...
}

Fix this by properly initializing the line pointer to NULL.

Link: https://lore.kernel.org/20260722130246.2135563-1-christian.gellermann@codasip.com
Link: https://lore.kernel.org/20260722130246.2135563-2-christian.gellermann@codasip.com
Link: https://pubs.opengroup.org/onlinepubs/9799919799/functions/getline.html [1]
Link: https://git.musl-libc.org/cgit/musl/tree/src/stdio/getdelim.c#n38 [2]
Fixes: 41585bbeeef9 ("selftests: add tests for clone3() with *set_tid")
Signed-off-by: Chris Gellermann 
Acked-by: David Hildenbrand (arm) 
Reviewed-by: Lorenzo Stoakes 
Cc: Christian Brauner 
Cc: Liam R. Howlett 
Cc: Lorenzo Stoakes 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Shuah Khan 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Cc: 
Signed-off-by: Andrew Morton

selftests/clone3: remove unused variables

2026-05-27T12:11:41+00:00

  clone3_cap_checkpoint_restore.c: In function 'call_clone3_set_tid':
  clone3_cap_checkpoint_restore.c:57:22: warning: unused variable 'tmp'
  [-Wunused-variable]
     57 |                 char tmp = 0;
        |                      ^~~
  clone3_cap_checkpoint_restore.c:56:21: warning: unused variable 'ret'
  [-Wunused-variable]
     56 |                 int ret;
        |                     ^~~
  clone3_cap_checkpoint_restore.c: In function 'clone3_cap_checkpoint_restore':
  clone3_cap_checkpoint_restore.c:138:13: warning: unused variable 'ret'
  [-Wunused-variable]
    138 |         int ret = 0;
        |             ^~~

Remove unused variables 'ret' and 'tmp' to fix -Wunused-variable
warnings.

Signed-off-by: Konstantin Khorenko 
Link: https://patch.msgid.link/20260524163840.34247-3-eva.kurchatova@virtuozzo.com
Signed-off-by: Christian Brauner (Amutable)

selftests/clone3: fix libcap interface usage

2026-05-27T12:11:41+00:00

The test's set_capability() function needs to set CAP_CHECKPOINT_RESTORE
(bit 40). But libcap's API (cap_set_flag) didn't support cap 40 when the
test was written - it was too new. So the author worked around it by
casting cap_t to an assumed internal layout.

This worked with older libcap versions where cap_t pointed directly to
that layout. Newer libcap internally restructured its cap_t opaque type.

Since 2.43, libcap natively supports CAP_CHECKPOINT_RESTORE, workaround
is no longer needed. The fix directly uses the library interface.

Signed-off-by: Eva Kurchatova 
Link: https://patch.msgid.link/20260524163840.34247-2-eva.kurchatova@virtuozzo.com
Signed-off-by: Christian Brauner (Amutable)

selftests: complete kselftest include centralization

2025-11-27T22:24:31+00:00

This follow-up patch completes centralization of kselftest.h and
ksefltest_harness.h includes in remaining seltests files, replacing all
relative paths with a non-relative paths using shared -I include path in
lib.mk

Tested with gcc-13.3 and clang-18.1, and cross-compiled successfully on
riscv, arm64, x86_64 and powerpc arch.

[reddybalavignesh9979@gmail.com: add selftests include path for kselftest.h]
  Link: https://lkml.kernel.org/r/20251017090201.317521-1-reddybalavignesh9979@gmail.com
Link: https://lkml.kernel.org/r/20251016104409.68985-1-reddybalavignesh9979@gmail.com
Signed-off-by: Bala-Vignesh-Reddy 
Suggested-by: Andrew Morton 
Link: https://lore.kernel.org/lkml/20250820143954.33d95635e504e94df01930d0@linux-foundation.org/
Reviewed-by: Wei Yang 
Cc: David Hildenbrand 
Cc: David S. Miller 
Cc: Eric Dumazet 
Cc: Günther Noack 
Cc: Jakub Kacinski 
Cc: Liam Howlett 
Cc: Lorenzo Stoakes 
Cc: Michal Hocko 
Cc: Mickael Salaun 
Cc: Ming Lei 
Cc: Paolo Abeni 
Cc: Shuah Khan 
Cc: Simon Horman 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

selftests/pidfd: fixes syscall number defines

2025-03-25T13:59:05+00:00

I had to spend some (a lot;) time to understand why pidfd_info_test
(and more) fails with my patch under qemu on my machine ;) Until I
applied the patch below.

I think it is a bad idea to do the things like

	#ifndef __NR_clone3
	#define __NR_clone3 -1
	#endif

because this can hide a problem. My working laptop runs Fedora-23 which
doesn't have __NR_clone3/etc in /usr/include/. So "make" happily succeeds,
but everything fails and it is not clear why.

Link: https://lore.kernel.org/r/20250323174518.GB834@redhat.com
Signed-off-by: Christian Brauner

clone3: clone3_cap_checkpoint_restore: remove unused MAX_PID_NS_LEVEL macro

2024-09-30T17:39:56+00:00

The macro MAX_PID_NS_LEVEL is never referenced in the code, so remove it.

Signed-off-by: Ba Jing 
Reviewed-by: Christian Brauner 
Signed-off-by: Shuah Khan

selftests/clone3: ksft_exit functions do not return

2024-05-06T19:57:20+00:00

After commit f7d5bcd35d42 ("selftests: kselftest: Mark functions that
unconditionally call exit() as __noreturn"), ksft_exit_...() functions
are marked as __noreturn, which means the return type should not be
'int' but 'void' because they are not returning anything (and never were
since exit() has always been called).

To facilitate updating the return type of these functions, remove
'return' before the calls to ksft_exit_{pass,fail}(), as __noreturn
prevents the compiler from warning that a caller of the ksft_exit
functions does not return a value because the program will terminate
upon calling these functions.

Just removing 'return' would have resulted in

  !ret ? ksft_exit_pass() : ksft_exit_fail();

so convert that into the more idiomatic

  if (ret)
    ksft_exit_fail();
  ksft_exit_pass();

Reviewed-by: Muhammad Usama Anjum 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Nathan Chancellor 
Signed-off-by: Shuah Khan

selftests/clone3: Correct log message for waitpid() failures

2024-05-06T19:57:20+00:00

When logging an error from calling waitpid() on the child we print a
misleading error message saying that the error we report was returned by
the chilld. Fix this to say the error is from waitpid().

Applied after fixing merge conflict:
Shuah Khan 

Signed-off-by: Mark Brown 
Signed-off-by: Shuah Khan

selftests/clone3: Check that the child exited cleanly

2024-05-06T19:57:20+00:00

When the child exits during the clone3() selftest we use WEXITSTATUS() to
get the exit status from the process without first checking WIFEXITED() to
see if the result will be valid. This can lead to incorrect results, for
example if the child exits due to signal. Add a WIFEXTED() check and report
any non-standard exit as a failure, using EXIT_FAILURE as the exit status
for call_clone3() since we otherwise report 0 or negative errnos.

Signed-off-by: Mark Brown 
Signed-off-by: Shuah Khan

selftests/clone3: Fix compiler warning

2024-05-06T19:57:20+00:00

Shuah reported a compiler warning with an Ubuntu GCC 13 build, I've been
unable to reproduce it but hopefully this fixes the issue:

clone3_set_tid.c:136:43: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘size_t’ {aka ‘long unsigned int’} [-Wformat=]

Reported-by: Shuah Khan 
Signed-off-by: Mark Brown 
Signed-off-by: Shuah Khan