Commit ff4e538c authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

page_pool: add a lockdep check for recycling in hardirq 



Page pool use in hardirq is prohibited, add debug checks
to catch misuses. IIRC we previously discussed using
DEBUG_NET_WARN_ON_ONCE() for this, but there were concerns
that people will have DEBUG_NET enabled in perf testing.
I don't think anyone enables lockdep in perf testing,
so use lockdep to avoid pushback and arguing :)

Acked-by: default avatarJesper Dangaard Brouer <hawk@kernel.org>
Signed-off-by: default avatarAlexander Lobakin <aleksander.lobakin@intel.com>
Reviewed-by: default avatarAlexander Duyck <alexanderduyck@fb.com>
Link: https://lore.kernel.org/r/20230804180529.2483231-6-aleksander.lobakin@intel.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 5b899c33

include/linux/lockdep.h

+7 −0
Original line number Diff line number Diff line
@@ -625,6 +625,12 @@ do { \ 
	WARN_ON_ONCE(__lockdep_enabled && !this_cpu_read(hardirq_context)); \

} while (0)



#define lockdep_assert_no_hardirq()					\

do {									\

	WARN_ON_ONCE(__lockdep_enabled && (this_cpu_read(hardirq_context) || \

					   !this_cpu_read(hardirqs_enabled))); \

} while (0)



#define lockdep_assert_preemption_enabled()				\

do {									\

	WARN_ON_ONCE(IS_ENABLED(CONFIG_PREEMPT_COUNT)	&&		\
@@ -659,6 +665,7 @@ do { \ 
# define lockdep_assert_irqs_enabled() do { } while (0)

# define lockdep_assert_irqs_disabled() do { } while (0)

# define lockdep_assert_in_irq() do { } while (0)

# define lockdep_assert_no_hardirq() do { } while (0)



# define lockdep_assert_preemption_enabled() do { } while (0)

# define lockdep_assert_preemption_disabled() do { } while (0)

net/core/page_pool.c

+2 −0
Original line number Diff line number Diff line
@@ -587,6 +587,8 @@ static __always_inline struct page * 
__page_pool_put_page(struct page_pool *pool, struct page *page,

		     unsigned int dma_sync_size, bool allow_direct)

{

	lockdep_assert_no_hardirq();



	/* This allocator is optimized for the XDP mode that uses

	 * one-frame-per-page, but have fallbacks that act like the

	 * regular page allocator APIs.