From: kbuild test robot <lkp@intel.com>
To: Mike Rapoport <rppt@linux.ibm.com>
Cc: kbuild-all@lists.01.org,
Andrew Morton <akpm@linux-foundation.org>,
Linux Memory Management List <linux-mm@kvack.org>
Subject: [linux-next:master 10679/10701] arch/x86/mm/pgtable.c:427:2: warning: variable length array 'u_pmds' is used
Date: Thu, 21 May 2020 03:56:53 +0800 [thread overview]
Message-ID: <202005210343.GBNjOjOX%lkp@intel.com> (raw)
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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@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@chromium.org>
:::::: CC: Ingo Molnar <mingo@kernel.org>
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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next reply other threads:[~2020-05-20 19:57 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 19:56 kbuild test robot [this message]
2020-05-20 20:58 ` Randy Dunlap
2020-05-20 23:11 ` Andrew Morton
2020-05-20 23:50 ` Randy Dunlap
2020-05-21 7:02 ` Mike Rapoport
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