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From: Jakub Sitnicki <jakub@cloudflare.com>
To: syzbot <syzbot+ec941d6e24f633a59172@syzkaller.appspotmail.com>
Cc: andrii@kernel.org,  ast@kernel.org,  bpf@vger.kernel.org,
  daniel@iogearbox.net,  davem@davemloft.net,  edumazet@google.com,
  john.fastabend@gmail.com,  kuba@kernel.org,
  linux-kernel@vger.kernel.org,  netdev@vger.kernel.org,
  pabeni@redhat.com,  syzkaller-bugs@googlegroups.com,
  xrivendell7@gmail.com
Subject: Re: [syzbot] [net?] [bpf?] possible deadlock in
 sock_hash_delete_elem (2)
In-Reply-To: <000000000000d0b87206170dd88f@google.com> (syzbot's message of
	"Fri, 26 Apr 2024 23:08:19 -0700")
References: <000000000000d0b87206170dd88f@google.com>
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Date: Tue, 21 May 2024 18:35:21 +0200
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#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git main

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 77da1f438bec..f6e694457886 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -8882,7 +8882,8 @@ static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id)
 	enum bpf_attach_type eatype = env->prog->expected_attach_type;
 	enum bpf_prog_type type = resolve_prog_type(env->prog);
 
-	if (func_id != BPF_FUNC_map_update_elem)
+	if (func_id != BPF_FUNC_map_update_elem &&
+	    func_id != BPF_FUNC_map_delete_elem)
 		return false;
 
 	/* It's not possible to get access to a locked struct sock in these
@@ -8988,7 +8989,6 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
 	case BPF_MAP_TYPE_SOCKMAP:
 		if (func_id != BPF_FUNC_sk_redirect_map &&
 		    func_id != BPF_FUNC_sock_map_update &&
-		    func_id != BPF_FUNC_map_delete_elem &&
 		    func_id != BPF_FUNC_msg_redirect_map &&
 		    func_id != BPF_FUNC_sk_select_reuseport &&
 		    func_id != BPF_FUNC_map_lookup_elem &&
@@ -8998,7 +8998,6 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
 	case BPF_MAP_TYPE_SOCKHASH:
 		if (func_id != BPF_FUNC_sk_redirect_hash &&
 		    func_id != BPF_FUNC_sock_hash_update &&
-		    func_id != BPF_FUNC_map_delete_elem &&
 		    func_id != BPF_FUNC_msg_redirect_hash &&
 		    func_id != BPF_FUNC_sk_select_reuseport &&
 		    func_id != BPF_FUNC_map_lookup_elem &&