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authorGuenter Roeck <linux@roeck-us.net>2018-03-01 14:40:52 -0800
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2018-03-02 12:48:40 +0100
commit61e18270f604c744ed9f8f1b740022516f9726f8 (patch)
treed9bb7e2c84e8bb877a51d015ddbd606b2652f9af /arch
parentd5feec04fe578c8dbd9e2e1439afc2f0af761ed4 (diff)
downloadlinux-61e18270f604c744ed9f8f1b740022516f9726f8.tar.gz
s390: Fix runtime warning about negative pgtables_bytes
When running s390 images with 'compat' processes, the following
BUG is seen repeatedly.

BUG: non-zero pgtables_bytes on freeing mm: -16384

Bisect points to commit b4e98d9ac775 ("mm: account pud page tables").
Analysis shows that init_new_context() is called with
mm->context.asce_limit set to _REGION3_SIZE. In this situation,
pgtables_bytes remains set to 0 and is not increased. The message is
displayed when the affected process dies and mm_dec_nr_puds() is called.

Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Fixes: b4e98d9ac775 ("mm: account pud page tables")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/s390/include/asm/mmu_context.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index 65154eaa3714..6c8ce15cde7b 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -63,6 +63,7 @@ static inline int init_new_context(struct task_struct *tsk,
 				   _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
 		/* pgd_alloc() did not account this pmd */
 		mm_inc_nr_pmds(mm);
+		mm_inc_nr_puds(mm);
 	}
 	crst_table_init((unsigned long *) mm->pgd, pgd_entry_type(mm));
 	return 0;