Martin Schwidefsky 4136161d67 s390/mm: fix mis-accounting of pgtable_bytes ... [ Upstream commit e12e4044ae ] In case a fork or a clone system fails in copy_process and the error handling does the mmput() at the bad_fork_cleanup_mm label, the following warning messages will appear on the console: BUG: non-zero pgtables_bytes on freeing mm: 16384 The reason for that is the tricks we play with mm_inc_nr_puds() and mm_inc_nr_pmds() in init_new_context(). A normal 64-bit process has 3 levels of page table, the p4d level and the pud level are folded. On process termination the free_pud_range() function in mm/memory.c will subtract 16KB from pgtable_bytes with a mm_dec_nr_puds() call, but there actually is not really a pud table. One issue with this is the fact that pgtable_bytes is usually off by a few kilobytes, but the more severe problem is that for a failed fork or clone the free_pgtables() function is not called. In this case there is no mm_dec_nr_puds() or mm_dec_nr_pmds() that go together with the mm_inc_nr_puds() and mm_inc_nr_pmds in init_new_context(). The pgtable_bytes will be off by 16384 or 32768 bytes and we get the BUG message. The message itself is purely cosmetic, but annoying. To fix this override the mm_pmd_folded, mm_pud_folded and mm_p4d_folded function to check for the true size of the address space. Reported-by: Li Wang <liwang@redhat.com> Tested-by: Li Wang <liwang@redhat.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2018-11-27 16:13:03 +01:00
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cmm.c	s390/cmm: avoid add_timer on concurrently used timer	2018-07-16 15:45:41 +02:00
dump_pagetables.c	s390: unify linker symbols usage	2018-02-27 08:05:23 +01:00
extmem.c	s390/extmem: fix gcc 8 stringop-overflow warning	2018-07-02 11:24:50 +02:00
fault.c	mm: convert return type of handle_mm_fault() caller to vm_fault_t	2018-08-17 16:20:28 -07:00
gmap.c	s390/mm: Check for valid vma before zapping in gmap_discard	2018-09-12 14:46:37 +02:00
gup.c	mm/gup.c: document return value	2018-04-13 17:10:27 -07:00
hugetlbpage.c	s390/mm: Clear skeys for newly mapped huge guest pmds	2018-07-30 11:20:18 +01:00
init.c	mm: pass the vmem_altmap to arch_remove_memory and __remove_pages	2018-01-08 11:46:23 -08:00
maccess.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
mem_detect.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
mmap.c	exec: pass stack rlimit into mm layout functions	2018-04-11 10:28:37 -07:00
page-states.c	s390/mm: fix addressing exception after suspend/resume	2018-08-09 08:05:48 +02:00
pageattr.c	s390/mm: Clear huge page storage keys on enable_skey	2018-07-30 11:20:18 +01:00
pgalloc.c	s390/mm: fix mis-accounting of pgtable_bytes	2018-11-27 16:13:03 +01:00
pgtable.c	s390/mm: Add huge page gmap linking support	2018-07-30 23:13:38 +02:00
vmem.c	mm: pass the vmem_altmap to vmemmap_free	2018-01-08 11:46:23 -08:00