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Message-ID: <202203291404.IHkCx1AG-lkp@intel.com>
Date: Tue, 29 Mar 2022 14:32:37 +0800
From: kernel test robot <lkp@...el.com>
To: "Gustavo A. R. Silva" <gustavoars@...nel.org>
Cc: llvm@...ts.linux.dev, kbuild-all@...ts.01.org,
"Gustavo A. R. Silva" <gustavo@...eddedor.com>,
LKML <linux-kernel@...r.kernel.org>
Subject: [gustavoars:testing/kspp-stringop-overflow 5/5]
arch/x86/mm/pgtable.c:442:27: warning: variable 'pmds' is uninitialized when
used here
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-a012-20220328 (https://download.01.org/0day-ci/archive/20220329/202203291404.IHkCx1AG-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 0f6d9501cf49ce02937099350d08f20c4af86f3d)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?id=d3becb16bbfe48ca524e4489b6c6c4fb1ccafa1a
git remote add gustavoars https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git
git fetch --no-tags gustavoars testing/kspp-stringop-overflow
git checkout d3becb16bbfe48ca524e4489b6c6c4fb1ccafa1a
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash arch/x86/mm/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>
All warnings (new ones prefixed by >>):
>> arch/x86/mm/pgtable.c:442:27: warning: variable 'pmds' is uninitialized when used here [-Wuninitialized]
if (preallocate_pmds(mm, pmds, PREALLOCATED_PMDS) != 0)
^~~~
arch/x86/mm/pgtable.c:432:14: note: initialize the variable 'pmds' to silence this warning
pmd_t **pmds;
^
= NULL
>> arch/x86/mm/pgtable.c:445:27: warning: variable 'u_pmds' is uninitialized when used here [-Wuninitialized]
if (preallocate_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS) != 0)
^~~~~~
arch/x86/mm/pgtable.c:431:16: note: initialize the variable 'u_pmds' to silence this warning
pmd_t **u_pmds;
^
= NULL
2 warnings generated.
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)
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 }
4f76cd382213b2 Jeremy Fitzhardinge 2008-03-17 475
:::::: The code at line 442 was first introduced by commit
:::::: f59dbe9ca6707eb7ffd0e24359085651c2d7df48 x86/pgtable/pae: Use separate kernel PMDs for user page-table
:::::: TO: Joerg Roedel <jroedel@...e.de>
:::::: CC: Thomas Gleixner <tglx@...utronix.de>
--
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https://01.org/lkp
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