[linux-next:master 10679/10701] arch/x86/mm/pgtable.c:427:2: warning: variable length array 'u_pmds' is used
5:56 a.m.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head: fb57b1fabcb28f358901b2df90abd2b48abc1ca8
commit: 0e19fc1c40bd7516d5a30a459db4f49d48910847 [10679/10701] mm: consolidate pgd_index()
and pgd_offset{_k}() definitions
config: i386-randconfig-a005-20200520 (attached as .config)
compiler: gcc-4.9 (Ubuntu 4.9.3-13ubuntu2) 4.9.3
reproduce:
git checkout 0e19fc1c40bd7516d5a30a459db4f49d48910847
# save the attached .config to linux build tree
make ARCH=i386
If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp(a)intel.com>
All warnings (new ones prefixed by >>, old ones prefixed by <<):
arch/x86/mm/pgtable.c: In function 'pgd_alloc':
> arch/x86/mm/pgtable.c:427:2: warning: variable length array
'u_pmds' is used [-Wvla]
pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS];
^
> arch/x86/mm/pgtable.c:428:2: warning: variable length array
'pmds' is used [-Wvla]
pmd_t *pmds[MAX_PREALLOCATED_PMDS];
^
vim +/u_pmds +427 arch/x86/mm/pgtable.c
1db491f77b6ed0 Fenghua Yu 2015-01-15 423
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 424 pgd_t *pgd_alloc(struct mm_struct
*mm)
1ec1fe73dfb711 Ingo Molnar 2008-03-19 425 {
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 426 pgd_t *pgd;
184d47f0fd3651 Kees Cook 2018-10-08 @427 pmd_t
*u_pmds[MAX_PREALLOCATED_USER_PMDS];
184d47f0fd3651 Kees Cook 2018-10-08 @428 pmd_t *pmds[MAX_PREALLOCATED_PMDS];
1ec1fe73dfb711 Ingo Molnar 2008-03-19 429
1db491f77b6ed0 Fenghua Yu 2015-01-15 430 pgd = _pgd_alloc();
1ec1fe73dfb711 Ingo Molnar 2008-03-19 431
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 432 if (pgd == NULL)
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 433 goto out;
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 434
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 435 mm->pgd = pgd;
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 436
f59dbe9ca6707e Joerg Roedel 2018-07-18 437 if (preallocate_pmds(mm, pmds,
PREALLOCATED_PMDS) != 0)
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 438 goto out_free_pgd;
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 439
f59dbe9ca6707e Joerg Roedel 2018-07-18 440 if (preallocate_pmds(mm, u_pmds,
PREALLOCATED_USER_PMDS) != 0)
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 441 goto out_free_pmds;
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 442
f59dbe9ca6707e Joerg Roedel 2018-07-18 443 if (paravirt_pgd_alloc(mm) != 0)
f59dbe9ca6707e Joerg Roedel 2018-07-18 444 goto out_free_user_pmds;
f59dbe9ca6707e Joerg Roedel 2018-07-18 445
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 446 /*
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 447 * Make sure that pre-populating the
pmds is atomic with
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 448 * respect to anything walking the
pgd_list, so that they
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 449 * never see a partially populated
pgd.
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 450 */
a79e53d85683c6 Andrea Arcangeli 2011-02-16 451 spin_lock(&pgd_lock);
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 452
617d34d9e5d832 Jeremy Fitzhardinge 2010-09-21 453 pgd_ctor(mm, pgd);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 454 pgd_prepopulate_pmd(mm, pgd, pmds);
f59dbe9ca6707e Joerg Roedel 2018-07-18 455 pgd_prepopulate_user_pmd(mm, pgd,
u_pmds);
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 456
a79e53d85683c6 Andrea Arcangeli 2011-02-16 457 spin_unlock(&pgd_lock);
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 458
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 459 return pgd;
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 460
f59dbe9ca6707e Joerg Roedel 2018-07-18 461 out_free_user_pmds:
f59dbe9ca6707e Joerg Roedel 2018-07-18 462 free_pmds(mm, u_pmds,
PREALLOCATED_USER_PMDS);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 463 out_free_pmds:
f59dbe9ca6707e Joerg Roedel 2018-07-18 464 free_pmds(mm, pmds,
PREALLOCATED_PMDS);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 465 out_free_pgd:
1db491f77b6ed0 Fenghua Yu 2015-01-15 466 _pgd_free(pgd);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 467 out:
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 468 return NULL;
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 469 }
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 470
:::::: The code at line 427 was first introduced by commit
:::::: 184d47f0fd365108bd06ab26cdb3450b716269fd x86/mm: Avoid VLA in pgd_alloc()
:::::: TO: Kees Cook <keescook(a)chromium.org>
:::::: CC: Ingo Molnar <mingo(a)kernel.org>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
6:58 a.m.
On 5/20/20 12:56 PM, kbuild test robot wrote:
tree:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head: fb57b1fabcb28f358901b2df90abd2b48abc1ca8
commit: 0e19fc1c40bd7516d5a30a459db4f49d48910847 [10679/10701] mm: consolidate
pgd_index() and pgd_offset{_k}() definitions
config: i386-randconfig-a005-20200520 (attached as .config)
compiler: gcc-4.9 (Ubuntu 4.9.3-13ubuntu2) 4.9.3
reproduce:
git checkout 0e19fc1c40bd7516d5a30a459db4f49d48910847
# save the attached .config to linux build tree
make ARCH=i386
If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp(a)intel.com>
All warnings (new ones prefixed by >>, old ones prefixed by <<):
arch/x86/mm/pgtable.c: In function 'pgd_alloc':
>> arch/x86/mm/pgtable.c:427:2: warning: variable length array 'u_pmds' is
used [-Wvla]
pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS];
^
>> arch/x86/mm/pgtable.c:428:2: warning: variable length array 'pmds' is
used [-Wvla]
pmd_t *pmds[MAX_PREALLOCATED_PMDS];
^
Yes, I also reported this on linux-next of 20200518 (but I didn't copy Mike on it).
vim +/u_pmds +427 arch/x86/mm/pgtable.c
1db491f77b6ed0 Fenghua Yu 2015-01-15 423
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 424 pgd_t *pgd_alloc(struct mm_struct
*mm)
1ec1fe73dfb711 Ingo Molnar 2008-03-19 425 {
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 426 pgd_t *pgd;
184d47f0fd3651 Kees Cook 2018-10-08 @427 pmd_t
*u_pmds[MAX_PREALLOCATED_USER_PMDS];
184d47f0fd3651 Kees Cook 2018-10-08 @428 pmd_t *pmds[MAX_PREALLOCATED_PMDS];
1ec1fe73dfb711 Ingo Molnar 2008-03-19 429
1db491f77b6ed0 Fenghua Yu 2015-01-15 430 pgd = _pgd_alloc();
1ec1fe73dfb711 Ingo Molnar 2008-03-19 431
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 432 if (pgd == NULL)
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 433 goto out;
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 434
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 435 mm->pgd = pgd;
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 436
f59dbe9ca6707e Joerg Roedel 2018-07-18 437 if (preallocate_pmds(mm, pmds,
PREALLOCATED_PMDS) != 0)
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 438 goto out_free_pgd;
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 439
f59dbe9ca6707e Joerg Roedel 2018-07-18 440 if (preallocate_pmds(mm, u_pmds,
PREALLOCATED_USER_PMDS) != 0)
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 441 goto out_free_pmds;
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 442
f59dbe9ca6707e Joerg Roedel 2018-07-18 443 if (paravirt_pgd_alloc(mm) != 0)
f59dbe9ca6707e Joerg Roedel 2018-07-18 444 goto out_free_user_pmds;
f59dbe9ca6707e Joerg Roedel 2018-07-18 445
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 446 /*
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 447 * Make sure that pre-populating the
pmds is atomic with
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 448 * respect to anything walking the
pgd_list, so that they
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 449 * never see a partially populated
pgd.
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 450 */
a79e53d85683c6 Andrea Arcangeli 2011-02-16 451 spin_lock(&pgd_lock);
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 452
617d34d9e5d832 Jeremy Fitzhardinge 2010-09-21 453 pgd_ctor(mm, pgd);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 454 pgd_prepopulate_pmd(mm, pgd, pmds);
f59dbe9ca6707e Joerg Roedel 2018-07-18 455 pgd_prepopulate_user_pmd(mm, pgd,
u_pmds);
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 456
a79e53d85683c6 Andrea Arcangeli 2011-02-16 457 spin_unlock(&pgd_lock);
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 458
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 459 return pgd;
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 460
f59dbe9ca6707e Joerg Roedel 2018-07-18 461 out_free_user_pmds:
f59dbe9ca6707e Joerg Roedel 2018-07-18 462 free_pmds(mm, u_pmds,
PREALLOCATED_USER_PMDS);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 463 out_free_pmds:
f59dbe9ca6707e Joerg Roedel 2018-07-18 464 free_pmds(mm, pmds,
PREALLOCATED_PMDS);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 465 out_free_pgd:
1db491f77b6ed0 Fenghua Yu 2015-01-15 466 _pgd_free(pgd);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 467 out:
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 468 return NULL;
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 469 }
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 470
:::::: The code at line 427 was first introduced by commit
:::::: 184d47f0fd365108bd06ab26cdb3450b716269fd x86/mm: Avoid VLA in pgd_alloc()
:::::: TO: Kees Cook <keescook(a)chromium.org>
:::::: CC: Ingo Molnar <mingo(a)kernel.org>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
--
~Randy
Reported-by: Randy Dunlap <rdunlap(a)infradead.org>
9:11 a.m.
On Thu, 21 May 2020 03:56:53 +0800 kbuild test robot <lkp(a)intel.com> wrote:
tree:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head: fb57b1fabcb28f358901b2df90abd2b48abc1ca8
commit: 0e19fc1c40bd7516d5a30a459db4f49d48910847 [10679/10701] mm: consolidate
pgd_index() and pgd_offset{_k}() definitions
config: i386-randconfig-a005-20200520 (attached as .config)
compiler: gcc-4.9 (Ubuntu 4.9.3-13ubuntu2) 4.9.3
reproduce:
git checkout 0e19fc1c40bd7516d5a30a459db4f49d48910847
# save the attached .config to linux build tree
make ARCH=i386
If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp(a)intel.com>
All warnings (new ones prefixed by >>, old ones prefixed by <<):
arch/x86/mm/pgtable.c: In function 'pgd_alloc':
>> arch/x86/mm/pgtable.c:427:2: warning: variable length array 'u_pmds' is
used [-Wvla]
pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS];
^
>> arch/x86/mm/pgtable.c:428:2: warning: variable length array 'pmds' is
used [-Wvla]
pmd_t *pmds[MAX_PREALLOCATED_PMDS];
^
Thanks. This works for me - perhaps Mike can come up with something smarter.
--- a/include/linux/pgtable.h~mm-consolidate-pgd_index-and-pgd_offset_k-definitions-fix
+++ a/include/linux/pgtable.h
@@ -62,11 +62,8 @@ static inline unsigned long pud_index(un
#endif
#ifndef pgd_index
-static inline unsigned long pgd_index(unsigned long address)
-{
- return ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1));
-}
-#define pgd_index pgd_index
+/* Must be a compile-time constant, so implement it as a macro */
+#define pgd_index(a) (((a) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
#endif
#ifndef pte_offset_kernel
_
9:50 a.m.
On 5/20/20 4:11 PM, Andrew Morton wrote:
On Thu, 21 May 2020 03:56:53 +0800 kbuild test robot
<lkp(a)intel.com> wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head: fb57b1fabcb28f358901b2df90abd2b48abc1ca8
> commit: 0e19fc1c40bd7516d5a30a459db4f49d48910847 [10679/10701] mm: consolidate
pgd_index() and pgd_offset{_k}() definitions
> config: i386-randconfig-a005-20200520 (attached as .config)
> compiler: gcc-4.9 (Ubuntu 4.9.3-13ubuntu2) 4.9.3
> reproduce:
> git checkout 0e19fc1c40bd7516d5a30a459db4f49d48910847
> # save the attached .config to linux build tree
> make ARCH=i386
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kbuild test robot <lkp(a)intel.com>
>
> All warnings (new ones prefixed by >>, old ones prefixed by <<):
>
> arch/x86/mm/pgtable.c: In function 'pgd_alloc':
>>> arch/x86/mm/pgtable.c:427:2: warning: variable length array 'u_pmds'
is used [-Wvla]
> pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS];
> ^
>>> arch/x86/mm/pgtable.c:428:2: warning: variable length array 'pmds' is
used [-Wvla]
> pmd_t *pmds[MAX_PREALLOCATED_PMDS];
> ^
Thanks. This works for me - perhaps Mike can come up with something smarter.
Works for me too. Thanks.
Acked-by: Randy Dunlap <rdunlap(a)infradead.org> # build-tested
---
a/include/linux/pgtable.h~mm-consolidate-pgd_index-and-pgd_offset_k-definitions-fix
+++ a/include/linux/pgtable.h
@@ -62,11 +62,8 @@ static inline unsigned long pud_index(un
#endif
#ifndef pgd_index
-static inline unsigned long pgd_index(unsigned long address)
-{
- return ((address >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1));
-}
-#define pgd_index pgd_index
+/* Must be a compile-time constant, so implement it as a macro */
+#define pgd_index(a) (((a) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
#endif
#ifndef pte_offset_kernel
_
--
~Randy
853
days inactive
853
days old
3 comments
3 participants
participants (3)
-
Andrew Morton -
kbuild test robot -
Randy Dunlap