[PATCH bpf-next 2/4] bpf: Use __GFP_NOWARN for kvmalloc_array() when attaching multiple kprobes

[Hou Tao <houtao@huaweicloud.com>]

From: Hou Tao <houtao1@huawei.com>

An abnormally big cnt may also be assigned to kprobe_multi.cnt when
attaching multiple kprobes. It will trigger the following warning in
kvmalloc_node():

	if (unlikely(size > INT_MAX)) {
	    WARN_ON_ONCE(!(flags & __GFP_NOWARN));
	    return NULL;
	}

Fix the warning by using __GFP_NOWARN when invoking kvmalloc_array() in
bpf_kprobe_multi_link_attach().

Fixes: 0dcac2725406 ("bpf: Add multi kprobe link")
Signed-off-by: Hou Tao <houtao1@huawei.com>
---
 kernel/trace/bpf_trace.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 07b9b5896d6c..64f200890c19 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2605,11 +2605,11 @@ static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32
 	int err = -ENOMEM;
 	unsigned int i;
 
-	syms = kvmalloc_array(cnt, sizeof(*syms), GFP_KERNEL);
+	syms = kvmalloc_array(cnt, sizeof(*syms), GFP_KERNEL | __GFP_NOWARN);
 	if (!syms)
 		goto error;
 
-	buf = kvmalloc_array(cnt, KSYM_NAME_LEN, GFP_KERNEL);
+	buf = kvmalloc_array(cnt, KSYM_NAME_LEN, GFP_KERNEL | __GFP_NOWARN);
 	if (!buf)
 		goto error;
 
@@ -2972,13 +2972,13 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 		return -EINVAL;
 
 	size = cnt * sizeof(*addrs);
-	addrs = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL);
+	addrs = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL | __GFP_NOWARN);
 	if (!addrs)
 		return -ENOMEM;
 
 	ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies);
 	if (ucookies) {
-		cookies = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL);
+		cookies = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL | __GFP_NOWARN);
 		if (!cookies) {
 			err = -ENOMEM;
 			goto error;
-- 
2.29.2