[PATCH 5/5] mm: constify the pte_offset_map_ro_nolock() return value
kernel test robot
lkp at intel.com
Fri Jul 24 10:06:07 PDT 2026
Hi Pedro,
kernel test robot noticed the following build warnings:
[auto build test WARNING on akpm-mm/mm-everything]
url: https://github.com/intel-lab-lkp/linux/commits/Pedro-Falcato/mm-constify-generic-pte_get/20260724-184321
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/20260724102017.141532-6-pfalcato%40suse.de
patch subject: [PATCH 5/5] mm: constify the pte_offset_map_ro_nolock() return value
config: s390-allnoconfig-bpf (https://download.01.org/0day-ci/archive/20260724/202607241905.9UNne8Y8-lkp@intel.com/config)
compiler: s390x-linux-gnu-gcc (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260724/202607241905.9UNne8Y8-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 at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202607241905.9UNne8Y8-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from arch/s390/kernel/asm-offsets.c:12:
./include/linux/pgtable.h: In function 'ptep_get_lockless':
>> ./include/linux/pgtable.h:782:25: warning: passing argument 1 of 'ptep_get' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
782 | return ptep_get(ptep);
| ^~~~
In file included from ./include/linux/pgtable.h:6:
./arch/s390/include/asm/pgtable.h:989:37: note: expected 'pte_t *' {aka 'long unsigned int *'} but argument is of type 'const pte_t *' {aka 'const long unsigned int *'}
989 | static inline pte_t ptep_get(pte_t *ptep)
| ~~~~~~~^~~~
--
In file included from ./include/linux/mm.h:31,
from ./arch/s390/include/asm/pgalloc.h:18,
from ./arch/s390/include/asm/mmu_context.h:11,
from ./arch/s390/include/asm/elf.h:173,
from ./include/linux/elf.h:6,
from ./include/linux/module.h:20,
from net/8021q/vlan.c:20:
./include/linux/pgtable.h: In function 'ptep_get_lockless':
>> ./include/linux/pgtable.h:782:25: warning: passing argument 1 of 'ptep_get' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
782 | return ptep_get(ptep);
| ^~~~
In file included from ./include/linux/pgtable.h:6:
./arch/s390/include/asm/pgtable.h:989:37: note: expected 'pte_t *' {aka 'long unsigned int *'} but argument is of type 'const pte_t *' {aka 'const long unsigned int *'}
989 | static inline pte_t ptep_get(pte_t *ptep)
| ~~~~~~~^~~~
net/8021q/vlan.c: In function 'register_vlan_device':
net/8021q/vlan.c:249:46: warning: '%i' directive output may be truncated writing between 1 and 4 bytes into a region of size between 0 and 15 [-Wformat-truncation=]
249 | snprintf(name, IFNAMSIZ, "%s.%i", real_dev->name, vlan_id);
| ^~
net/8021q/vlan.c:249:42: note: directive argument in the range [0, 4094]
249 | snprintf(name, IFNAMSIZ, "%s.%i", real_dev->name, vlan_id);
| ^~~~~~~
net/8021q/vlan.c:249:17: note: 'snprintf' output between 3 and 21 bytes into a destination of size 16
249 | snprintf(name, IFNAMSIZ, "%s.%i", real_dev->name, vlan_id);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
net/8021q/vlan.c:237:46: warning: '%.4i' directive output may be truncated writing 4 bytes into a region of size between 0 and 15 [-Wformat-truncation=]
237 | snprintf(name, IFNAMSIZ, "%s.%.4i", real_dev->name, vlan_id);
| ^~~~
net/8021q/vlan.c:237:42: note: directive argument in the range [0, 4094]
237 | snprintf(name, IFNAMSIZ, "%s.%.4i", real_dev->name, vlan_id);
| ^~~~~~~~~
net/8021q/vlan.c:237:17: note: 'snprintf' output between 6 and 21 bytes into a destination of size 16
237 | snprintf(name, IFNAMSIZ, "%s.%.4i", real_dev->name, vlan_id);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
In file included from ./include/linux/mm.h:31,
from ./arch/s390/include/asm/pgalloc.h:18,
from ./arch/s390/include/asm/mmu_context.h:11,
from ./arch/s390/include/asm/elf.h:173,
from ./include/linux/elf.h:6,
from ./include/linux/module.h:20,
from net/netfilter/ipvs/ip_vs_core.c:24:
./include/linux/pgtable.h: In function 'ptep_get_lockless':
>> ./include/linux/pgtable.h:782:25: warning: passing argument 1 of 'ptep_get' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
782 | return ptep_get(ptep);
| ^~~~
In file included from ./include/linux/pgtable.h:6:
./arch/s390/include/asm/pgtable.h:989:37: note: expected 'pte_t *' {aka 'long unsigned int *'} but argument is of type 'const pte_t *' {aka 'const long unsigned int *'}
989 | static inline pte_t ptep_get(pte_t *ptep)
| ~~~~~~~^~~~
net/netfilter/ipvs/ip_vs_core.c: In function 'ip_vs_in_icmp':
net/netfilter/ipvs/ip_vs_core.c:1768:15: warning: variable 'outer_proto' set but not used [-Wunused-but-set-variable]
1768 | char *outer_proto = "IPIP";
| ^~~~~~~~~~~
vim +782 ./include/linux/pgtable.h
024d232ae4fcd7 Peter Zijlstra 2020-11-26 775
2a4a06da8a4b93 Peter Zijlstra 2020-11-13 776 /*
2a4a06da8a4b93 Peter Zijlstra 2020-11-13 777 * We require that the PTE can be read atomically.
2a4a06da8a4b93 Peter Zijlstra 2020-11-13 778 */
024d232ae4fcd7 Peter Zijlstra 2020-11-26 779 #ifndef ptep_get_lockless
3cfe4c8a2f30c7 Pedro Falcato 2026-07-24 780 static inline pte_t ptep_get_lockless(const pte_t *ptep)
2a4a06da8a4b93 Peter Zijlstra 2020-11-13 781 {
2a4a06da8a4b93 Peter Zijlstra 2020-11-13 @782 return ptep_get(ptep);
2a4a06da8a4b93 Peter Zijlstra 2020-11-13 783 }
024d232ae4fcd7 Peter Zijlstra 2020-11-26 784 #endif
024d232ae4fcd7 Peter Zijlstra 2020-11-26 785
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