prep_new_page() will allocate memory in some scenarios. Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:96 ___might_sleep.cold+0x1f1/0x237 kernel/sched/core.c:9153 prepare_alloc_pages+0x3da/0x580 mm/page_alloc.c:5179 __alloc_pages+0x12f/0x500 mm/page_alloc.c:5375 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2272 stack_depot_save+0x39d/0x4e0 lib/stackdepot.c:303 save_stack+0x15e/0x1e0 mm/page_owner.c:120 __set_page_owner+0x50/0x290 mm/page_owner.c:181 prep_new_page mm/page_alloc.c:2445 [inline] __alloc_pages_bulk+0x8b9/0x1870 mm/page_alloc.c:5313 So we add GFP_ATOMIC and remove GFP_KERNEL flag. Reported-and-tested-by: syzbot+b07d8440edb5f8988eea@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Wang Qing <wangqing@xxxxxxxx> --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d6e94cc..3016ba5 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5309,7 +5309,7 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, } nr_account++; - prep_new_page(page, 0, gfp, 0); + prep_new_page(page, 0, gfp | GFP_ATOMIC & ~GFP_KERNEL, 0); if (page_list) list_add(&page->lru, page_list); else -- 2.7.4
