[PATCH 1/2] mm/page_alloc: don't spin_trylock() in NMI on UP
Brendan Jackman <[email protected]>
| Newsgroups | dev.linux.lists.linux-rt-devel,org.kernel.vger.linux-kernel,org.kernel.vger.stable,org.kvack.linux-mm |
|---|---|
| Message-ID | <[email protected]> |
As noted in can_spin_trylock(), using this is unsafe in this context.
commit 620b46ed6ae17 ("mm/page_alloc: return NULL early from
alloc_frozen_pages_nolock() in NMI on UP") fixed this on the alloc side
but missed the free side.
Reported-by: [email protected]
Link: https://sashiko.dev/#/patchset/[email protected]
Cc: [email protected]
Fixes: d7242af86434 ("mm: Introduce alloc_frozen_pages_nolock()")
Signed-off-by: Brendan Jackman <[email protected]>
---
mm/page_alloc.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9c97a86da2b9f..5fe1c11f919d7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2979,8 +2979,7 @@ static void __free_frozen_pages(struct page *page, unsigned int order,
migratetype = MIGRATE_MOVABLE;
}
- if (unlikely((fpi_flags & FPI_TRYLOCK) && IS_ENABLED(CONFIG_PREEMPT_RT)
- && (in_nmi() || in_hardirq()))) {
+ if (unlikely((fpi_flags & FPI_TRYLOCK) && !can_spin_trylock())) {
add_page_to_zone_llist(zone, page, order);
return;
}
--
2.54.0