From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
If we first remove the SLAB flag followed by the PFMEMALLOC flag then the
removal of the latter will trigger the VM_BUG_ON() as it can be seen in
| kernel BUG at include/linux/page-flags.h:474!
| invalid opcode: 0000 [#1] PREEMPT SMP
| Call Trace:
| [<c10e2d77>] slab_destroy+0x27/0x70
| [<c10e3285>] drain_freelist+0x55/0x90
| [<c10e344e>] __cache_shrink+0x6e/0x90
| [<c14e3211>] ? acpi_sleep_init+0xcf/0xcf
| [<c10e349d>] kmem_cache_shrink+0x2d/0x40
because the SLAB flag is gone. This patch simply changes the order.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
mm/slab.c | 2 +-
mm/slub.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/slab.c b/mm/slab.c
index 00c601b..b1a39f7 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2007,8 +2007,8 @@ static void kmem_freepages(struct kmem_cache *cachep, void *addr)
NR_SLAB_UNRECLAIMABLE, nr_freed);
while (i--) {
BUG_ON(!PageSlab(page));
- __ClearPageSlab(page);
__ClearPageSlabPfmemalloc(page);
+ __ClearPageSlab(page);
page++;
}
if (current->reclaim_state)
diff --git a/mm/slub.c b/mm/slub.c
index f8cbec4..d753146 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1417,8 +1417,8 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
-pages);
- __ClearPageSlab(page);
__ClearPageSlabPfmemalloc(page);
+ __ClearPageSlab(page);
reset_page_mapcount(page);
if (current->reclaim_state)
current->reclaim_state->reclaimed_slab += pages;
--
1.7.10
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