* mm/hugetlb_cgroup.c:829:44: warning: '%s' directive output may be truncated writing up to 1623 bytes into a region of size between 32 and 63
@ 2025-12-21 15:23 kernel test robot
2025-12-23 1:16 ` Xiujianfeng
0 siblings, 1 reply; 4+ messages in thread
From: kernel test robot @ 2025-12-21 15:23 UTC (permalink / raw)
To: Xiu Jianfeng
Cc: oe-kbuild-all, linux-kernel, Andrew Morton, Linux Memory Management List
Hi Xiu,
FYI, the error/warning still remains.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 9094662f6707d1d4b53d18baba459604e8bb0783
commit: 47179fe03588caa13a9bae642b058901709ddc55 mm/hugetlb_cgroup: prepare cftypes based on template
date: 1 year, 6 months ago
config: s390-randconfig-001-20251220 (https://download.01.org/0day-ci/archive/20251221/202512212332.9lFRbgdS-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251221/202512212332.9lFRbgdS-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/202512212332.9lFRbgdS-lkp@intel.com/
All warnings (new ones prefixed by >>):
mm/hugetlb_cgroup.c: In function 'hugetlb_cgroup_file_init':
>> mm/hugetlb_cgroup.c:829:44: warning: '%s' directive output may be truncated writing up to 1623 bytes into a region of size between 32 and 63 [-Wformat-truncation=]
829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
| ^~
mm/hugetlb_cgroup.c:829:3: note: 'snprintf' output between 2 and 1656 bytes into a destination of size 64
829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/hugetlb_cgroup.c:829:44: warning: '%s' directive output may be truncated writing up to 2087 bytes into a region of size between 32 and 63 [-Wformat-truncation=]
829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
| ^~
mm/hugetlb_cgroup.c:829:3: note: 'snprintf' output between 2 and 2120 bytes into a destination of size 64
829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
vim +829 mm/hugetlb_cgroup.c
815
816 static void __init
817 hugetlb_cgroup_cfttypes_init(struct hstate *h, struct cftype *cft,
818 struct cftype *tmpl, int tmpl_size)
819 {
820 char buf[32];
821 int i, idx = hstate_index(h);
822
823 /* format the size */
824 mem_fmt(buf, sizeof(buf), huge_page_size(h));
825
826 for (i = 0; i < tmpl_size; cft++, tmpl++, i++) {
827 *cft = *tmpl;
828 /* rebuild the name */
> 829 snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
830 /* rebuild the private */
831 cft->private = MEMFILE_PRIVATE(idx, tmpl->private);
832 /* rebuild the file_offset */
833 if (tmpl->file_offset) {
834 unsigned int offset = tmpl->file_offset;
835
836 cft->file_offset = MEMFILE_OFFSET0(offset) +
837 MEMFILE_FIELD_SIZE(offset) * idx;
838 }
839
840 lockdep_register_key(&cft->lockdep_key);
841 }
842 }
843
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: mm/hugetlb_cgroup.c:829:44: warning: '%s' directive output may be truncated writing up to 1623 bytes into a region of size between 32 and 63
2025-12-21 15:23 mm/hugetlb_cgroup.c:829:44: warning: '%s' directive output may be truncated writing up to 1623 bytes into a region of size between 32 and 63 kernel test robot
@ 2025-12-23 1:16 ` Xiujianfeng
0 siblings, 0 replies; 4+ messages in thread
From: Xiujianfeng @ 2025-12-23 1:16 UTC (permalink / raw)
To: kernel test robot, Xiu Jianfeng
Cc: oe-kbuild-all, linux-kernel, Andrew Morton, Linux Memory Management List
On 12/21/2025 11:23 PM, kernel test robot wrote:
> Hi Xiu,
>
> FYI, the error/warning still remains.
>
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head: 9094662f6707d1d4b53d18baba459604e8bb0783
> commit: 47179fe03588caa13a9bae642b058901709ddc55 mm/hugetlb_cgroup: prepare cftypes based on template
> date: 1 year, 6 months ago
> config: s390-randconfig-001-20251220 (https://download.01.org/0day-ci/archive/20251221/202512212332.9lFRbgdS-lkp@intel.com/config)
> compiler: s390-linux-gcc (GCC) 10.5.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251221/202512212332.9lFRbgdS-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/202512212332.9lFRbgdS-lkp@intel.com/
Thank you, the fix patch is on the way:
https://lore.kernel.org/all/20251222072359.3626182-1-xiujianfeng@huaweicloud.com/
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: mm/hugetlb_cgroup.c:829:44: warning: '%s' directive output may be truncated writing up to 1623 bytes into a region of size between 32 and 63
2025-07-18 8:39 kernel test robot
@ 2025-07-18 15:27 ` Joshua Hahn
0 siblings, 0 replies; 4+ messages in thread
From: Joshua Hahn @ 2025-07-18 15:27 UTC (permalink / raw)
To: kernel test robot
Cc: Xiu Jianfeng, oe-kbuild-all, linux-kernel, Andrew Morton,
Linux Memory Management List
On Fri, 18 Jul 2025 16:39:59 +0800 kernel test robot <lkp@intel.com> wrote:
> mm/hugetlb_cgroup.c: In function 'hugetlb_cgroup_file_init':
> >> mm/hugetlb_cgroup.c:829:44: warning: '%s' directive output may be truncated writing up to 1623 bytes into a region of size between 32 and 63 [-Wformat-truncation=]
> 829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
> | ^~
> mm/hugetlb_cgroup.c:829:3: note: 'snprintf' output between 2 and 1656 bytes into a destination of size 64
> 829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> mm/hugetlb_cgroup.c:829:44: warning: '%s' directive output may be truncated writing up to 2087 bytes into a region of size between 32 and 63 [-Wformat-truncation=]
> 829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
> | ^~
> mm/hugetlb_cgroup.c:829:3: note: 'snprintf' output between 2 and 2120 bytes into a destination of size 64
> 829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In theory,
#define MAX_CFTYPE_NAME = 64
sizeof(cft->name) = MAX_CFTYPE_NAME
sizeof(buf) = 32
sizeof(tmpl->name) = MAX_CFTYPE_NAME
But in practice there should never really be an overflow, since the longest
name so far "rsvd.max_usage_in_bytes" is 23 characters long and the longest
hugepage size string is "64KB" or "32MB"...
Unless someone makes a horrendously long name, I think we should be good.
With that said, char *mem_fmt only returns strings of up to 4 characters long.
Maybe we can shrink sizeof(buf) to be 4 and explicitly truncate the last
5 bytes (account for '.') of tmpl->name? I can spin something up.
Curious what others think though. Is this fix necessary? We really should
never overflow anyways.
Thank you Kernel Test Robot!
Joshua
Sent using hkml (https://github.com/sjp38/hackermail)
^ permalink raw reply [flat|nested] 4+ messages in thread
* mm/hugetlb_cgroup.c:829:44: warning: '%s' directive output may be truncated writing up to 1623 bytes into a region of size between 32 and 63
@ 2025-07-18 8:39 kernel test robot
2025-07-18 15:27 ` Joshua Hahn
0 siblings, 1 reply; 4+ messages in thread
From: kernel test robot @ 2025-07-18 8:39 UTC (permalink / raw)
To: Xiu Jianfeng
Cc: oe-kbuild-all, linux-kernel, Andrew Morton, Linux Memory Management List
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 6832a9317eee280117cd695fa885b2b7a7a38daf
commit: 47179fe03588caa13a9bae642b058901709ddc55 mm/hugetlb_cgroup: prepare cftypes based on template
date: 1 year ago
config: s390-randconfig-r132-20250718 (https://download.01.org/0day-ci/archive/20250718/202507181808.mpbc1F0r-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 10.5.0
reproduce: (https://download.01.org/0day-ci/archive/20250718/202507181808.mpbc1F0r-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/202507181808.mpbc1F0r-lkp@intel.com/
All warnings (new ones prefixed by >>):
mm/hugetlb_cgroup.c: In function 'hugetlb_cgroup_file_init':
>> mm/hugetlb_cgroup.c:829:44: warning: '%s' directive output may be truncated writing up to 1623 bytes into a region of size between 32 and 63 [-Wformat-truncation=]
829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
| ^~
mm/hugetlb_cgroup.c:829:3: note: 'snprintf' output between 2 and 1656 bytes into a destination of size 64
829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/hugetlb_cgroup.c:829:44: warning: '%s' directive output may be truncated writing up to 2087 bytes into a region of size between 32 and 63 [-Wformat-truncation=]
829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
| ^~
mm/hugetlb_cgroup.c:829:3: note: 'snprintf' output between 2 and 2120 bytes into a destination of size 64
829 | snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
vim +829 mm/hugetlb_cgroup.c
815
816 static void __init
817 hugetlb_cgroup_cfttypes_init(struct hstate *h, struct cftype *cft,
818 struct cftype *tmpl, int tmpl_size)
819 {
820 char buf[32];
821 int i, idx = hstate_index(h);
822
823 /* format the size */
824 mem_fmt(buf, sizeof(buf), huge_page_size(h));
825
826 for (i = 0; i < tmpl_size; cft++, tmpl++, i++) {
827 *cft = *tmpl;
828 /* rebuild the name */
> 829 snprintf(cft->name, MAX_CFTYPE_NAME, "%s.%s", buf, tmpl->name);
830 /* rebuild the private */
831 cft->private = MEMFILE_PRIVATE(idx, tmpl->private);
832 /* rebuild the file_offset */
833 if (tmpl->file_offset) {
834 unsigned int offset = tmpl->file_offset;
835
836 cft->file_offset = MEMFILE_OFFSET0(offset) +
837 MEMFILE_FIELD_SIZE(offset) * idx;
838 }
839
840 lockdep_register_key(&cft->lockdep_key);
841 }
842 }
843
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 4+ messages in thread
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