The patch titled
Subject: test_hexdump: avoid string truncation warning
has been added to the -mm mm-nonmm-unstable branch. Its filename is
test_hexdump-avoid-string-truncation-warning.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/test_hexdump-avoid-string-truncation-warning.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Arnd Bergmann <arnd@xxxxxxxx>
Subject: test_hexdump: avoid string truncation warning
Date: Tue, 9 Apr 2024 16:00:54 +0200
gcc can warn when a string is too long to fit into the strncpy()
destination buffer, as it is here depending on the function arguments:
inlined from 'test_hexdump_prepare_test.constprop' at /home/arnd/arm-soc/lib/test_hexdump.c:116:3:
include/linux/fortify-string.h:108:33: error: '__builtin_strncpy' output truncated copying between 0 and 32 bytes from a string of length 32 [-Werror=stringop-truncation]
108 | #define __underlying_strncpy __builtin_strncpy
| ^
include/linux/fortify-string.h:187:16: note: in expansion of macro '__underlying_strncpy'
187 | return __underlying_strncpy(p, q, size);
| ^~~~~~~~~~~~~~~~~~~~
The intention here is to copy exactly 'l' bytes without any padding or
NUL-termination, so the most logical change is to use memcpy(), just as
a previous change adapted the other output from strncpy() to memcpy().
Link: https://lkml.kernel.org/r/20240409140059.3806717-2-arnd@xxxxxxxxxx
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Justin Stitt <justinstitt@xxxxxxxxxx>
Cc: Alexey Starikovskiy <astarikovskiy@xxxxxxx>
Cc: Bob Moore <robert.moore@xxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: Lin Ming <ming.m.lin@xxxxxxxxx>
Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Nicolas Schier <nicolas@xxxxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: "Richard Russon (FlatCap)" <ldm@xxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/test_hexdump.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/lib/test_hexdump.c~test_hexdump-avoid-string-truncation-warning
+++ a/lib/test_hexdump.c
@@ -113,7 +113,7 @@ static void __init test_hexdump_prepare_
*p++ = ' ';
} while (p < test + rs * 2 + rs / gs + 1);
- strncpy(p, data_a, l);
+ memcpy(p, data_a, l);
p += l;
}
_
Patches currently in -mm which might be from arnd@xxxxxxxx are
fix-missing-vmalloch-includes-fix-5.patch
kcov-avoid-clang-out-of-range-warning.patch
test_hexdump-avoid-string-truncation-warning.patch
block-partitions-ldm-convert-strncpy-to-strscpy.patch
blktrace-convert-strncpy-to-strscpy_pad.patch
