[gustavoars:testing/kspp-stringop-overflow 5/5] arch/x86/mm/pgtable.c:442 pgd_alloc() error: uninitialized symbol 'pmds'.
From: Dan Carpenter
Date: Tue Mar 29 2022 - 05:28:55 EST
tree: https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git testing/kspp-stringop-overflow
head: d3becb16bbfe48ca524e4489b6c6c4fb1ccafa1a
commit: d3becb16bbfe48ca524e4489b6c6c4fb1ccafa1a [5/5] mm/pgtable: Fix Wstringop-overflow warnings in pgd_alloc()
config: i386-randconfig-m021-20220328 (https://download.01.org/0day-ci/archive/20220329/202203291451.bKVdLfSv-lkp@xxxxxxxxx/config)
compiler: gcc-9 (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
New smatch warnings:
arch/x86/mm/pgtable.c:442 pgd_alloc() error: uninitialized symbol 'pmds'.
arch/x86/mm/pgtable.c:445 pgd_alloc() error: uninitialized symbol 'u_pmds'.
Old smatch warnings:
arch/x86/mm/pgtable.c:281 pgd_mop_up_pmds() warn: we never enter this loop
vim +/pmds +442 arch/x86/mm/pgtable.c
1ec1fe73dfb711 Ingo Molnar 2008-03-19 434
1db491f77b6ed0 Fenghua Yu 2015-01-15 435 pgd = _pgd_alloc();
1ec1fe73dfb711 Ingo Molnar 2008-03-19 436
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 437 if (pgd == NULL)
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 438 goto out;
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 439
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 440 mm->pgd = pgd;
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 441
f59dbe9ca6707e Joerg Roedel 2018-07-18 @442 if (preallocate_pmds(mm, pmds, PREALLOCATED_PMDS) != 0)
This can be either an array or a pointer depending on the .config
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 443 goto out_free_pgd;
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 444
f59dbe9ca6707e Joerg Roedel 2018-07-18 @445 if (preallocate_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS) != 0)
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 446 goto out_free_pmds;
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 447
f59dbe9ca6707e Joerg Roedel 2018-07-18 448 if (paravirt_pgd_alloc(mm) != 0)
f59dbe9ca6707e Joerg Roedel 2018-07-18 449 goto out_free_user_pmds;
f59dbe9ca6707e Joerg Roedel 2018-07-18 450
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 451 /*
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 452 * Make sure that pre-populating the pmds is atomic with
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 453 * respect to anything walking the pgd_list, so that they
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 454 * never see a partially populated pgd.
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 455 */
a79e53d85683c6 Andrea Arcangeli 2011-02-16 456 spin_lock(&pgd_lock);
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 457
617d34d9e5d832 Jeremy Fitzhardinge 2010-09-21 458 pgd_ctor(mm, pgd);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 459 pgd_prepopulate_pmd(mm, pgd, pmds);
f59dbe9ca6707e Joerg Roedel 2018-07-18 460 pgd_prepopulate_user_pmd(mm, pgd, u_pmds);
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 461
a79e53d85683c6 Andrea Arcangeli 2011-02-16 462 spin_unlock(&pgd_lock);
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 463
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 464 return pgd;
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 465
f59dbe9ca6707e Joerg Roedel 2018-07-18 466 out_free_user_pmds:
f59dbe9ca6707e Joerg Roedel 2018-07-18 467 free_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 468 out_free_pmds:
f59dbe9ca6707e Joerg Roedel 2018-07-18 469 free_pmds(mm, pmds, PREALLOCATED_PMDS);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 470 out_free_pgd:
1db491f77b6ed0 Fenghua Yu 2015-01-15 471 _pgd_free(pgd);
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 472 out:
d8d5900ef8afc5 Jeremy Fitzhardinge 2008-06-25 473 return NULL;
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 474 }
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