lib/cmdline.c | 19 ++++++++++++++----- lib/kstrtox.c | 1 - 2 files changed, 14 insertions(+), 6 deletions(-)
From 161367fd1e8b41e938274923bbb3d26de69f7a7e Mon Sep 17 00:00:00 2001
From: Alexey Dobriyan <adobriyan@gmail.com>
Date: Thu, 17 Sep 2026 18:49:18 +0300
Subject: [PATCH 1/1] kstrtox: delete saturation in case of overflow
Partially revert
commit 6e30111dbb4075e3c26c230417b32bc4a1c66831
lib: fix _parse_integer_limit() to handle overflow
Originally, kstrto* was written in a way to keep simple_strto*()
functions as is, so that they continue to return incorrect result
if integer overflow occurs.
Saturation doesn't do anything useful, it just creates second incorrect
value and potentially breaks simple_strto*() users.
Caller can decide to saturate itself anyway.
Move saturation to memparse() from where the idea came from.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
lib/cmdline.c | 19 ++++++++++++++-----
lib/kstrtox.c | 1 -
2 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/lib/cmdline.c b/lib/cmdline.c
index 16cce6621cec..7f9859733fb5 100644
--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -14,6 +14,8 @@
#include <linux/string.h>
#include <linux/ctype.h>
+#include "kstrtox.h"
+
/*
* If a hyphen was found in get_option, this will handle the
* range of numbers, M-N. This will expand the range and insert
@@ -146,14 +148,21 @@ EXPORT_SYMBOL(get_options);
* Parses a string into a number. The number stored at @ptr is
* potentially suffixed with K, M, G, T, P, E.
*
- * Return: The value as recognized by simple_strtoull() multiplied
- * by the value as specified by suffix, if any.
+ * Return: The value multiplied by the value as specified by suffix, if any.
*/
unsigned long long memparse(const char *ptr, char **retptr)
{
- char *endptr; /* local pointer to end of parsed string */
- unsigned long long ret = simple_strtoull(ptr, &endptr, 0);
+ unsigned int base = 0;
+ ptr = _parse_integer_fixup_radix(ptr, &base);
+ unsigned long long ret;
+ unsigned int rv = _parse_integer(ptr, base, &ret);
+ if (rv & KSTRTOX_OVERFLOW) {
+ rv &= ~KSTRTOX_OVERFLOW;
+ ret = -1;
+ }
+ /* local pointer to end of parsed string */
+ const char *endptr = ptr + rv;
unsigned int shl = 0;
/* Consume valid suffix even in case of overflow. */
@@ -194,7 +203,7 @@ unsigned long long memparse(const char *ptr, char **retptr)
}
if (retptr)
- *retptr = endptr;
+ *retptr = (char *)endptr;
return ret;
}
diff --git a/lib/kstrtox.c b/lib/kstrtox.c
index bac1c057e1b0..dcbc613fcde6 100644
--- a/lib/kstrtox.c
+++ b/lib/kstrtox.c
@@ -85,7 +85,6 @@ unsigned int _parse_integer_limit(const char *s, unsigned int base, unsigned lon
if (unlikely(res & (~0ull << 60))) {
if (check_mul_overflow(res, base, &res) ||
check_add_overflow(res, val, &res)) {
- res = ULLONG_MAX;
overflow = KSTRTOX_OVERFLOW;
}
} else {
--
2.55.0Hi Alexey, kernel test robot noticed the following build errors: [auto build test ERROR on akpm-mm/mm-nonmm-unstable] [also build test ERROR on akpm-mm/mm-everything linus/master v7.3-rc4 next-20260921] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Alexey-Dobriyan/kstrtox-delete-saturation-in-case-of-overflow/20260917-191707 base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-nonmm-unstable patch link: https://lore.kernel.org/r/a396f2ea-8de8-4eca-a216-ff69bc40fe85%40p183 patch subject: [PATCH] kstrtox: delete saturation in case of overflow config: riscv-allnoconfig (https://download.01.org/0day-ci/archive/20260922/202609221939.FSyfaCW4-lkp@intel.com/config) compiler: riscv64-linux-gcc (GCC) 16.1.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260922/202609221939.FSyfaCW4-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202609221939.FSyfaCW4-lkp@intel.com/ All errors (new ones prefixed by >>): riscv64-linux-ld: ./drivers/firmware/efi/libstub/lib-cmdline.stub.o: in function `__efistub_memparse': >> __efistub_cmdline.c:(.init.text+0x13a): undefined reference to `__efistub__parse_integer_fixup_radix' >> riscv64-linux-ld: __efistub_cmdline.c:(.init.text+0x154): undefined reference to `__efistub__parse_integer_limit' riscv64-linux-ld: .tmp_vmlinux1: hidden symbol `__efistub__parse_integer_fixup_radix' isn't defined riscv64-linux-ld: final link failed: bad value -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
Hi Alexey, kernel test robot noticed the following build errors: [auto build test ERROR on akpm-mm/mm-nonmm-unstable] [also build test ERROR on akpm-mm/mm-everything linus/master v7.3-rc4 next-20260921] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Alexey-Dobriyan/kstrtox-delete-saturation-in-case-of-overflow/20260917-191707 base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-nonmm-unstable patch link: https://lore.kernel.org/r/a396f2ea-8de8-4eca-a216-ff69bc40fe85%40p183 patch subject: [PATCH] kstrtox: delete saturation in case of overflow config: s390-allnoconfig (https://download.01.org/0day-ci/archive/20260922/202609221929.OSikd7q0-lkp@intel.com/config) compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project 5dc57157f12f0ff676e823d9b4d98b45c07e5df2) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260922/202609221929.OSikd7q0-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202609221929.OSikd7q0-lkp@intel.com/ All errors (new ones prefixed by >>): >> ld.lld: error: undefined symbol: _parse_integer_fixup_radix >>> referenced by cmdline.c >>> arch/s390/boot/cmdline.o:(memparse) -- >> ld.lld: error: undefined symbol: _parse_integer_limit >>> referenced by cmdline.c >>> arch/s390/boot/cmdline.o:(memparse) -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
On Thu, Sep 17, 2026 at 07:17:07PM +0300, Alexey Dobriyan wrote:
> From 161367fd1e8b41e938274923bbb3d26de69f7a7e Mon Sep 17 00:00:00 2001
> From: Alexey Dobriyan <adobriyan@gmail.com>
> Date: Thu, 17 Sep 2026 18:49:18 +0300
> Subject: [PATCH 1/1] kstrtox: delete saturation in case of overflow
Dunno if this is okay to have in the body. I think you need to use some korg
tools to send mails in a better way.
> Partially revert
>
> commit 6e30111dbb4075e3c26c230417b32bc4a1c66831
> lib: fix _parse_integer_limit() to handle overflow
The reference to the commit is standardized:
commit 6e30111dbb40 ("lib: fix _parse_integer_limit() to handle overflow")
> Originally, kstrto* was written in a way to keep simple_strto*()
> functions as is, so that they continue to return incorrect result
> if integer overflow occurs.
>
> Saturation doesn't do anything useful, it just creates second incorrect
> value and potentially breaks simple_strto*() users.
>
> Caller can decide to saturate itself anyway.
>
> Move saturation to memparse() from where the idea came from.
I don't see the use of this saturation, so perhaps we indeed can live without
it as before (note, I haven't checked any POSIX/C standards for the conversions,
dunno if they specify that kind of behaviour).
...
All above assuming that test cases are passed as before.
--
With Best Regards,
Andy Shevchenko
On Thu, 17 Sep 2026 19:17:07 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote: > >From 161367fd1e8b41e938274923bbb3d26de69f7a7e Mon Sep 17 00:00:00 2001 > From: Alexey Dobriyan <adobriyan@gmail.com> > Date: Thu, 17 Sep 2026 18:49:18 +0300 > Subject: [PATCH 1/1] kstrtox: delete saturation in case of overflow > > Partially revert > > commit 6e30111dbb4075e3c26c230417b32bc4a1c66831 > lib: fix _parse_integer_limit() to handle overflow > > Originally, kstrto* was written in a way to keep simple_strto*() > functions as is, so that they continue to return incorrect result > if integer overflow occurs. > > Saturation doesn't do anything useful, it just creates second incorrect > value and potentially breaks simple_strto*() users. > > Caller can decide to saturate itself anyway. > > Move saturation to memparse() from where the idea came from. I don't know what this patch does :( Can we define/explain "saturation"? Should we be updating lib/tests/cmdline_kunit.c when altering memparse?
© 2016 - 2026 Red Hat, Inc.