linux-kernel - Re: [syzbot] [bpf?] general protection fault in bpf_get_local

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Message-Id: <20251231031754.299998-1-buaajxlj@163.com>
Date: Wed, 31 Dec 2025 11:17:54 +0800
From: Liang Jie <buaajxlj@....com>
To: syzbot+4fe468a3f7fac86ea2c9@...kaller.appspotmail.com
Cc: andrii@...nel.org,
	ast@...nel.org,
	bpf@...r.kernel.org,
	daniel@...earbox.net,
	eddyz87@...il.com,
	haoluo@...gle.com,
	john.fastabend@...il.com,
	jolsa@...nel.org,
	kpsingh@...nel.org,
	linux-kernel@...r.kernel.org,
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	syzkaller-bugs@...glegroups.com,
	yonghong.song@...ux.dev,
	liangjie@...iang.com
Subject: Re: [syzbot] [bpf?] general protection fault in bpf_get_local_storage (2)

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 3f0e9c8cefa9

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 69988af44b37..2bc27ece5cc5 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -1768,6 +1768,9 @@ BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags)
        ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
        storage = ctx->prog_item->cgroup_storage[stype];
 
+       if (unlikely(!storage))
+               return (unsigned long)NULL;
+
        if (stype == BPF_CGROUP_STORAGE_SHARED)
                ptr = &READ_ONCE(storage->buf)->data[0];