Vlastimil Babka c87cbc1f00 mm, hotplug: fix page online with DEBUG_PAGEALLOC compiled but not enabled ... Commit cd02cf1ace ("mm/hotplug: fix an imbalance with DEBUG_PAGEALLOC") fixed memory hotplug with debug_pagealloc enabled, where onlining a page goes through page freeing, which removes the direct mapping. Some arches don't like when the page is not mapped in the first place, so generic_online_page() maps it first. This is somewhat wasteful, but better than special casing page freeing fast paths. The commit however missed that DEBUG_PAGEALLOC configured doesn't mean it's actually enabled. One has to test debug_pagealloc_enabled() since 031bc5743f ("mm/debug-pagealloc: make debug-pagealloc boottime configurable"), or alternatively debug_pagealloc_enabled_static() since 8e57f8acbb ("mm, debug_pagealloc: don't rely on static keys too early"), but this is not done. As a result, a s390 kernel with DEBUG_PAGEALLOC configured but not enabled will crash: Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 0000000000000000 TEID: 0000000000000483 Fault in home space mode while using kernel ASCE. AS:0000001ece13400b R2:000003fff7fd000b R3:000003fff7fcc007 S:000003fff7fd7000 P:000000000000013d Oops: 0004 ilc:2 [#1] SMP CPU: 1 PID: 26015 Comm: chmem Kdump: loaded Tainted: GX 5.3.18-5-default #1 SLE15-SP2 (unreleased) Krnl PSW : 0704e00180000000 0000001ecd281b9e (__kernel_map_pages+0x166/0x188) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0000000000000000 0000000000000800 0000400b00000000 0000000000000100 0000000000000001 0000000000000000 0000000000000002 0000000000000100 0000001ece139230 0000001ecdd98d40 0000400b00000100 0000000000000000 000003ffa17e4000 001fffe0114f7d08 0000001ecd4d93ea 001fffe0114f7b20 Krnl Code: 0000001ecd281b8e: ec17ffff00d8 ahik %r1,%r7,-1 0000001ecd281b94: ec111dbc0355 risbg %r1,%r1,29,188,3 >0000001ecd281b9e: 94fb5006 ni 6(%r5),251 0000001ecd281ba2: 41505008 la %r5,8(%r5) 0000001ecd281ba6: ec51fffc6064 cgrj %r5,%r1,6,1ecd281b9e 0000001ecd281bac: 1a07 ar %r0,%r7 0000001ecd281bae: ec03ff584076 crj %r0,%r3,4,1ecd281a5e Call Trace: [<0000001ecd281b9e>] __kernel_map_pages+0x166/0x188 [<0000001ecd4d9516>] online_pages_range+0xf6/0x128 [<0000001ecd2a8186>] walk_system_ram_range+0x7e/0xd8 [<0000001ecda28aae>] online_pages+0x2fe/0x3f0 [<0000001ecd7d02a6>] memory_subsys_online+0x8e/0xc0 [<0000001ecd7add42>] device_online+0x5a/0xc8 [<0000001ecd7d0430>] state_store+0x88/0x118 [<0000001ecd5b9f62>] kernfs_fop_write+0xc2/0x200 [<0000001ecd5064b6>] vfs_write+0x176/0x1e0 [<0000001ecd50676a>] ksys_write+0xa2/0x100 [<0000001ecda315d4>] system_call+0xd8/0x2c8 Fix this by checking debug_pagealloc_enabled_static() before calling kernel_map_pages(). Backports for kernel before 5.5 should use debug_pagealloc_enabled() instead. Also add comments. Fixes: cd02cf1ace ("mm/hotplug: fix an imbalance with DEBUG_PAGEALLOC") Reported-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: <stable@vger.kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Qian Cai <cai@lca.pw> Link: http://lkml.kernel.org/r/20200224094651.18257-1-vbabka@suse.cz Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2020-03-06 07:06:09 -06:00
..
kasan	RISC-V Patches for the 5.6 Merge Window, Part 1	2020-01-31 11:23:29 -08:00
backing-dev.c	memcg: fix a crash in wb_workfn when a device disappears	2020-01-31 10:30:36 -08:00
balloon_compaction.c	mm/balloon_compaction: suppress allocation warnings	2019-09-04 07:42:01 -04:00
cleancache.c	Driver Core and debugfs changes for 5.3-rc1	2019-07-12 12:24:03 -07:00
cma_debug.c	mm/cma_debug.c: use DEFINE_DEBUGFS_ATTRIBUTE to define debugfs fops	2019-12-01 12:59:09 -08:00
cma.c	mm/cma.c: switch to bitmap_zalloc() for cma bitmap allocation	2019-12-01 12:59:09 -08:00
cma.h
compaction.c	mm, compaction: fix wrong pfn handling in __reset_isolation_pfn()	2019-10-14 15:04:01 -07:00
debug_page_ref.c
debug.c	mm/hotplug: silence a lockdep splat with printk()	2020-01-31 10:30:39 -08:00
dmapool.c	mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options	2019-07-12 11:05:46 -07:00
early_ioremap.c	mm/early_ioremap.c: use %pa to print resource_size_t variables	2020-01-31 10:30:38 -08:00
fadvise.c	fs: Export generic_fadvise()	2019-08-30 22:43:58 -07:00
failslab.c	mm/failslab.c: by default, do not fail allocations with direct reclaim only	2019-07-12 11:05:43 -07:00
filemap.c	mm/filemap.c: clean up filemap_write_and_wait()	2020-01-31 10:30:37 -08:00
frame_vector.c	mm: untag user pointers in get_vaddr_frames	2019-09-25 17:51:41 -07:00
frontswap.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 482	2019-06-19 17:09:52 +02:00
gup_benchmark.c	mm/gup_benchmark: use proper FOLL_WRITE flags instead of hard-coding "1"	2020-01-31 10:30:38 -08:00
gup.c	asm-generic/tlb: rename HAVE_RCU_TABLE_FREE	2020-02-04 03:05:26 +00:00
highmem.c	mm, x86/mm: Untangle address space layout definitions from basic pgtable type definitions	2019-12-10 10:12:55 +01:00
hmm.c	mm: pagewalk: add 'depth' parameter to pte_hole	2020-02-04 03:05:25 +00:00
huge_memory.c	mm: fix possible PMD dirty bit lost in set_pmd_migration_entry()	2020-03-06 07:06:09 -06:00
hugetlb_cgroup.c	mm: hugetlb controller for cgroups v2	2019-12-16 12:41:40 -08:00
hugetlb.c	mm/hugetlb: defer freeing of huge pages if in non-task context	2020-01-04 13:55:09 -08:00
hwpoison-inject.c	mm/hwpoison-inject: use DEFINE_DEBUGFS_ATTRIBUTE to define debugfs fops	2019-12-01 12:59:09 -08:00
init-mm.c	mm/init-mm.c: include <linux/mman.h> for vm_committed_as_batch	2019-10-19 06:32:32 -04:00
internal.h	mm, pcpu: make zone pcp updates and reset internal to the mm	2019-12-01 12:59:06 -08:00
interval_tree.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 248	2019-06-19 17:09:08 +02:00
Kconfig	mm/Kconfig: fix trivial help text punctuation	2019-12-01 12:59:10 -08:00
Kconfig.debug	mm: add generic ptdump	2020-02-04 03:05:25 +00:00
khugepaged.c	mm/thp: flush file for !is_shmem PageDirty() case in collapse_file()	2019-12-01 12:59:09 -08:00
kmemleak-test.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333	2019-06-05 17:37:06 +02:00
kmemleak.c	mm/kmemleak: turn kmemleak_lock and object->lock to raw_spinlock_t	2020-01-31 10:30:36 -08:00
ksm.c	* PPC secure guest support	2019-12-04 11:08:30 -08:00
list_lru.c	mm: memcg/slab: stop setting page->mem_cgroup pointer for slab pages	2019-07-12 11:05:44 -07:00
maccess.c	uaccess: Add strict non-pagefault kernel-space read function	2019-11-02 12:39:12 -07:00
madvise.c	mm: make do_madvise() available internally	2020-01-20 17:04:02 -07:00
Makefile	mm: add generic ptdump	2020-02-04 03:05:25 +00:00
mapping_dirty_helpers.c	mm: Add write-protect and clean utilities for address space ranges	2019-11-06 13:03:36 +01:00
memblock.c	memblock: Use __func__ in remaining memblock_dbg() call sites	2020-01-31 10:30:38 -08:00
memcontrol.c	mm/memcontrol.c: lost css_put in memcg_expand_shrinker_maps()	2020-02-21 11:22:15 -08:00
memfd.c	mm: page cache: store only head pages in i_pages	2019-09-24 15:54:08 -07:00
memory_hotplug.c	mm, hotplug: fix page online with DEBUG_PAGEALLOC compiled but not enabled	2020-03-06 07:06:09 -06:00
memory-failure.c	mm/memory-failure.c: use page_shift() in add_to_kill()	2019-12-01 12:59:04 -08:00
memory.c	mm: avoid data corruption on CoW fault into PFN-mapped VMA	2020-03-06 07:06:09 -06:00
mempolicy.c	mm/mempolicy.c: fix out of bounds write in mpol_parse_str()	2020-01-31 10:30:36 -08:00
mempool.c
memremap.c	mm/memory_hotplug: poison memmap in remove_pfn_range_from_zone()	2020-02-04 03:05:23 +00:00
memtest.c
migrate.c	mm: pagewalk: add 'depth' parameter to pte_hole	2020-02-04 03:05:25 +00:00
mincore.c	mm: pagewalk: add 'depth' parameter to pte_hole	2020-02-04 03:05:25 +00:00
mlock.c	mm: untag user pointers passed to memory syscalls	2019-09-25 17:51:41 -07:00
mm_init.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
mmap.c	mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()	2020-02-20 10:03:14 +00:00
mmu_context.c
mmu_gather.c	asm-generic/tlb: provide MMU_GATHER_TABLE_FREE	2020-02-04 03:05:26 +00:00
mmu_notifier.c	mm/mmu_notifiers: Use 'interval_sub' as the variable for mmu_interval_notifier	2020-01-14 11:54:47 -04:00
mmzone.c
mprotect.c	mm, numa: fix bad pmd by atomically check for pmd_trans_huge when marking page tables prot_numa	2020-03-06 07:06:09 -06:00
mremap.c	mm: Avoid creating virtual address aliases in brk()/mmap()/mremap()	2020-02-20 10:03:14 +00:00
msync.c	mm: untag user pointers passed to memory syscalls	2019-09-25 17:51:41 -07:00
nommu.c	mm/mmap.c: rb_parent is not necessary in __vma_link_list()	2019-12-01 06:29:19 -08:00
oom_kill.c	mm, oom: dump stack of victim when reaping failed	2020-01-31 10:30:38 -08:00
page_alloc.c	mm/memmap_init: update variable name in memmap_init_zone	2020-02-04 03:05:23 +00:00
page_counter.c
page_ext.c	mm, page_owner: fix off-by-one error in __set_page_owner_handle()	2019-10-14 15:04:00 -07:00
page_idle.c	mm/page_idle.c: fix oops because end_pfn is larger than max_pfn	2019-06-29 16:43:45 +08:00
page_io.c	fs: Enable bmap() function to properly return errors	2020-02-03 08:05:37 -05:00
page_isolation.c	mm/page_isolation: fix potential warning from user	2020-01-31 10:30:39 -08:00
page_owner.c	mm/page_owner: don't access uninitialized memmaps when reading /proc/pagetypeinfo	2019-10-19 06:32:31 -04:00
page_poison.c	mm/page_poison.c: fix a typo in a comment	2019-09-24 15:54:08 -07:00
page_vma_mapped.c	mm/page_vma_mapped.c: explicitly compare pfn for normal, hugetlbfs and THP page	2020-01-31 10:30:38 -08:00
page-writeback.c	mm/page-writeback.c: improve arithmetic divisions	2020-01-13 18:19:02 -08:00
pagewalk.c	x86: mm: avoid allocating struct mm_struct on the stack	2020-02-04 03:05:25 +00:00
percpu-internal.h	percpu: convert chunk hints to be based on pcpu_block_md	2019-03-13 12:25:31 -07:00
percpu-km.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428	2019-06-05 17:37:16 +02:00
percpu-stats.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428	2019-06-05 17:37:16 +02:00
percpu-vm.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428	2019-06-05 17:37:16 +02:00
percpu.c	bitmap: genericize percpu bitmap region iterators	2020-01-20 16:40:56 +01:00
pgtable-generic.c	asm-generic/mm: stub out p{4,u}d_clear_bad() if __PAGETABLE_P{4,U}D_FOLDED	2019-12-01 06:29:19 -08:00
process_vm_access.c	mm, tree-wide: rename put_user_page*() to unpin_user_page*()	2020-01-31 10:30:38 -08:00
ptdump.c	x86: mm: avoid allocating struct mm_struct on the stack	2020-02-04 03:05:25 +00:00
readahead.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
rmap.c	mm, thp: do not queue fully unmapped pages for deferred split	2019-12-01 12:59:09 -08:00
rodata_test.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441	2019-06-05 17:37:17 +02:00
shmem.c	tmpfs: deny and force are not huge mount options	2020-02-18 15:07:30 -05:00
shuffle.c	mm: fix -Wmissing-prototypes warnings	2019-10-07 15:47:19 -07:00
shuffle.h	mm: maintain randomization of page free lists	2019-05-14 19:52:48 -07:00
slab_common.c	proc: convert everything to "struct proc_ops"	2020-02-04 03:05:26 +00:00
slab.c	mm, debug_pagealloc: don't rely on static keys too early	2020-01-13 18:19:02 -08:00
slab.h	mm: clean up and clarify lruvec lookup procedure	2019-12-01 12:59:06 -08:00
slob.c	mm, sl[aou]b: guarantee natural alignment for kmalloc(power-of-two)	2019-10-07 15:47:20 -07:00
slub.c	mm/slub.c: avoid slub allocation while holding list_lock	2020-01-31 10:30:36 -08:00
sparse-vmemmap.c	mm/sparsemem: convert kmalloc_section_memmap() to populate_section_memmap()	2019-07-18 17:08:07 -07:00
sparse.c	mm/sparsemem: pfn_to_page is not valid yet on SPARSEMEM	2020-02-21 11:22:15 -08:00
swap_cgroup.c
swap_slots.c
swap_state.c	mm: page cache: store only head pages in i_pages	2019-09-24 15:54:08 -07:00
swap.c	mm: devmap: refactor 1-based refcounting for ZONE_DEVICE pages	2020-01-31 10:30:37 -08:00
swapfile.c	mm/swapfile.c: fix a comment in sys_swapon()	2020-02-21 11:22:15 -08:00
truncate.c	mm/thp: allow dropping THP from page cache	2019-10-19 06:32:33 -04:00
usercopy.c	usercopy: Avoid HIGHMEM pfn warning	2019-09-17 15:20:17 -07:00
userfaultfd.c	mm: fix typos in comments when calling __SetPageUptodate()	2019-12-01 12:59:10 -08:00
util.c	mm/mmap.c: rb_parent is not necessary in __vma_link_list()	2019-12-01 06:29:19 -08:00
vmacache.c
vmalloc.c	Linux 5.5-rc7	2020-01-20 08:05:16 +01:00
vmpressure.c	mm/vmpressure.c: fix a signedness bug in vmpressure_register_event()	2019-10-07 15:47:19 -07:00
vmscan.c	mm/vmscan.c: don't round up scan size for online memory cgroup	2020-02-21 11:22:15 -08:00
vmstat.c	mm/memcontrol: use vmstat names for printing statistics	2019-12-04 19:44:11 -08:00
workingset.c	mm: vmscan: detect file thrashing at the reclaim root	2019-12-01 12:59:07 -08:00
z3fold.c	mm/z3fold.c: do not include rwlock.h directly	2020-03-06 07:06:09 -06:00
zbud.c	treewide: Add SPDX license identifier for more missed files	2019-05-21 10:50:45 +02:00
zpool.c	zpool: add malloc_support_movable to zpool_driver	2019-09-24 15:54:12 -07:00
zsmalloc.c	mm/zsmalloc.c: fix the migrated zspage statistics.	2020-01-04 13:55:09 -08:00
zswap.c	zswap: potential NULL dereference on error in init_zswap()	2020-01-31 10:30:39 -08:00