linux-kernel - [PATCH] mm:slub:avoid wake up kswapd in set_track

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Message-ID: <20250801065121.876793-1-yangshiguang1011@163.com>
Date: Fri,  1 Aug 2025 14:51:21 +0800
From: yangshiguang1011@....com
To: vbabka@...e.cz
Cc: akpm@...ux-foundation.org,
	cl@...two.org,
	rientjes@...gle.com,
	roman.gushchin@...ux.dev,
	harry.yoo@...cle.com,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	yangshiguang <yangshiguang1011@....com>
Subject: [PATCH] mm:slub:avoid wake up kswapd in set_track_prepare

From: yangshiguang <yangshiguang1011@....com>

set_track_prepare() can incur lock recursion.
The issue is that it is called from hrtimer_start_range_ns
holding the per_cpu(hrtimer_bases)[n].lock, but when enabled
CONFIG_DEBUG_OBJECTS_TIMERS, may wake up kswapd in set_track_prepare,
and try to hold the per_cpu(hrtimer_bases)[n].lock.

So avoid waking up kswapd.The oops looks something like:

BUG: spinlock recursion on CPU#3, swapper/3/0
 lock: 0xffffff8a4bf29c80, .magic: dead4ead, .owner: swapper/3/0, .owner_cpu: 3
Hardware name: Qualcomm Technologies, Inc. Popsicle based on SM8850 (DT)
Call trace:
spin_bug+0x0
_raw_spin_lock_irqsave+0x80
hrtimer_try_to_cancel+0x94
task_contending+0x10c
enqueue_dl_entity+0x2a4
dl_server_start+0x74
enqueue_task_fair+0x568
enqueue_task+0xac
do_activate_task+0x14c
ttwu_do_activate+0xcc
try_to_wake_up+0x6c8
default_wake_function+0x20
autoremove_wake_function+0x1c
__wake_up+0xac
wakeup_kswapd+0x19c
wake_all_kswapds+0x78
__alloc_pages_slowpath+0x1ac
__alloc_pages_noprof+0x298
stack_depot_save_flags+0x6b0
stack_depot_save+0x14
set_track_prepare+0x5c
___slab_alloc+0xccc
__kmalloc_cache_noprof+0x470
__set_page_owner+0x2bc
post_alloc_hook[jt]+0x1b8
prep_new_page+0x28
get_page_from_freelist+0x1edc
__alloc_pages_noprof+0x13c
alloc_slab_page+0x244
allocate_slab+0x7c
___slab_alloc+0x8e8
kmem_cache_alloc_noprof+0x450
debug_objects_fill_pool+0x22c
debug_object_activate+0x40
enqueue_hrtimer[jt]+0xdc
hrtimer_start_range_ns+0x5f8
...

Signed-off-by: yangshiguang <yangshiguang1011@....com>
---
 mm/slub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/slub.c b/mm/slub.c
index cf7c6032d5fd..14e3bac0c6ad 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -969,7 +969,7 @@ static noinline depot_stack_handle_t set_track_prepare(void)
 	unsigned int nr_entries;

 	nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
-	handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
+	handle = stack_depot_save(entries, nr_entries, __GFP_NOWARN);

 	return handle;
 }
-- 
2.43.0