From e3540e5a7054d6daaf9a1415a48aacb092112a89 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Tue, 9 Jul 2024 11:14:08 +0200
Subject: [PATCH] Revert "bpf: Take return from set_memory_ro() into account
 with bpf_prog_lock_ro()"

This reverts commit fdd411af8178edc6b7bf260f8fa4fba1bedd0a6d which is
commit 7d2cc63eca0c993c99d18893214abf8f85d566d8 upstream.

It is part of a series that is reported to both break the arm64 builds
and instantly crashes the powerpc systems at the first load of a bpf
program.  So revert it for now until it can come back in a safe way.

Reported-by: matoro <matoro_mailinglist_kernel@matoro.tk>
Reported-by: Vitaly Chikunov <vt@altlinux.org>
Reported-by: WangYuli <wangyuli@uniontech.com>
Link: https://lore.kernel.org/r/5A29E00D83AB84E3+20240706031101.637601-1-wangyuli@uniontech.com
Link: https://lore.kernel.org/r/cf736c5e37489e7dc7ffd67b9de2ab47@matoro.tk
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Song Liu <song@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Kees Cook <keescook@chromium.org>
Cc: Puranjay Mohan <puranjay12@gmail.com>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>  # s390x
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>  # LoongArch
Cc: Johan Almbladh <johan.almbladh@anyfinetworks.com> # MIPS Part
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/filter.h | 5 ++---
 kernel/bpf/core.c      | 4 +---
 kernel/bpf/verifier.c  | 8 ++------
 3 files changed, 5 insertions(+), 12 deletions(-)

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 5a2800ec94ea..5090e940ba3e 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -842,15 +842,14 @@ bpf_ctx_narrow_access_offset(u32 off, u32 size, u32 size_default)
 
 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
 
-static inline int __must_check bpf_prog_lock_ro(struct bpf_prog *fp)
+static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 {
 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
 	if (!fp->jited) {
 		set_vm_flush_reset_perms(fp);
-		return set_memory_ro((unsigned long)fp, fp->pages);
+		set_memory_ro((unsigned long)fp, fp->pages);
 	}
 #endif
-	return 0;
 }
 
 static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 77a9b12e00af..4124805ad7ba 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2375,9 +2375,7 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
 	}
 
 finalize:
-	*err = bpf_prog_lock_ro(fp);
-	if (*err)
-		return fp;
+	bpf_prog_lock_ro(fp);
 
 	/* The tail call compatibility check can only be done at
 	 * this late stage as we need to determine, if we deal
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index aa546355918c..171045b6956d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -18625,13 +18625,9 @@ static int jit_subprogs(struct bpf_verifier_env *env)
 	 * bpf_prog_load will add the kallsyms for the main program.
 	 */
 	for (i = 1; i < env->subprog_cnt; i++) {
-		err = bpf_prog_lock_ro(func[i]);
-		if (err)
-			goto out_free;
-	}
-
-	for (i = 1; i < env->subprog_cnt; i++)
+		bpf_prog_lock_ro(func[i]);
 		bpf_prog_kallsyms_add(func[i]);
+	}
 
 	/* Last step: make now unused interpreter insns from main
 	 * prog consistent for later dump requests, so they can