diff options
| author | Mel Gorman <mgorman@techsingularity.net> | 2021-06-28 19:41:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-29 10:53:54 -0700 |
| commit | 56f0e661ea8c0178e80048df7166653a51ef2c3d (patch) | |
| tree | de8b30f37a9ada9446e148c0d8cac061f0849a78 | |
| parent | 43c95bcc51e4e7f3e3cbce01515fe429a4cf12a7 (diff) | |
mm/page_alloc: explicitly acquire the zone lock in __free_pages_ok
__free_pages_ok() disables IRQs before calling a common helper
free_one_page() that acquires the zone lock. This is not safe according
to Documentation/locking/locktypes.rst and in this context, IRQ disabling
is not protecting a per_cpu_pages structure either or a local_lock would
be used.
This patch explicitly acquires the lock with spin_lock_irqsave instead of
relying on a helper. This removes the last instance of local_irq_save()
in page_alloc.c.
Link: https://lkml.kernel.org/r/20210512095458.30632-8-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/page_alloc.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 161bcda61520..f1a51c163e75 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1590,21 +1590,21 @@ static void __free_pages_ok(struct page *page, unsigned int order, unsigned long flags; int migratetype; unsigned long pfn = page_to_pfn(page); + struct zone *zone = page_zone(page); if (!free_pages_prepare(page, order, true, fpi_flags)) return; migratetype = get_pfnblock_migratetype(page, pfn); - /* - * TODO FIX: Disable IRQs before acquiring IRQ-safe zone->lock - * and protect vmstat updates. - */ - local_irq_save(flags); + spin_lock_irqsave(&zone->lock, flags); __count_vm_events(PGFREE, 1 << order); - free_one_page(page_zone(page), page, pfn, order, migratetype, - fpi_flags); - local_irq_restore(flags); + if (unlikely(has_isolate_pageblock(zone) || + is_migrate_isolate(migratetype))) { + migratetype = get_pfnblock_migratetype(page, pfn); + } + __free_one_page(page, pfn, zone, order, migratetype, fpi_flags); + spin_unlock_irqrestore(&zone->lock, flags); } void __free_pages_core(struct page *page, unsigned int order) |