From 31f23a6a181c81543b10a1a9056b0e6c7ef1c747 Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Thu, 17 Sep 2020 15:44:53 +0800 Subject: bpf: Fix potential call bpf_link_free() in atomic context The in_atomic() macro cannot always detect atomic context, in particular, it cannot know about held spinlocks in non-preemptible kernels. Although, there is no user call bpf_link_put() with holding spinlock now, be on the safe side, so we can avoid this in the future. Signed-off-by: Muchun Song Signed-off-by: Daniel Borkmann Acked-by: Song Liu Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200917074453.20621-1-songmuchun@bytedance.com --- kernel/bpf/syscall.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 2ce32cad5c8e..ec68d3a23a2b 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2345,12 +2345,8 @@ void bpf_link_put(struct bpf_link *link) if (!atomic64_dec_and_test(&link->refcnt)) return; - if (in_atomic()) { - INIT_WORK(&link->work, bpf_link_put_deferred); - schedule_work(&link->work); - } else { - bpf_link_free(link); - } + INIT_WORK(&link->work, bpf_link_put_deferred); + schedule_work(&link->work); } static int bpf_link_release(struct inode *inode, struct file *filp) -- cgit v1.2.3