From: Andrea Righi <arighi@nvidia.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@fomichev.me>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] bpf: do not inline bpf_get_smp_processor_id() with CONFIG_SMP disabled
Date: Mon, 16 Dec 2024 11:46:15 +0100 [thread overview]
Message-ID: <20241216104615.503706-1-arighi@nvidia.com> (raw)
Calling bpf_get_smp_processor_id() in a kernel with CONFIG_SMP disabled
can trigger the following bug, as pcpu_hot is unavailable:
[ 8.471774] BUG: unable to handle page fault for address: 00000000936a290c
[ 8.471849] #PF: supervisor read access in kernel mode
[ 8.471881] #PF: error_code(0x0000) - not-present page
Fix by preventing the inlining of bpf_get_smp_processor_id() when
CONFIG_SMP disabled.
Fixes: 1ae6921009e5 ("bpf: inline bpf_get_smp_processor_id() helper")
Signed-off-by: Andrea Righi <arighi@nvidia.com>
---
kernel/bpf/verifier.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f7f892a52a37..d85413f1a784 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -21272,7 +21272,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
goto next_insn;
}
-#if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
+#if defined(CONFIG_SMP) && defined(CONFIG_X86_64) && !defined(CONFIG_UML)
/* Implement bpf_get_smp_processor_id() inline. */
if (insn->imm == BPF_FUNC_get_smp_processor_id &&
verifier_inlines_helper_call(env, insn->imm)) {
--
2.47.1
next reply other threads:[~2024-12-16 10:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-16 10:46 Andrea Righi [this message]
2024-12-16 16:16 ` [PATCH] bpf: do not inline bpf_get_smp_processor_id() with CONFIG_SMP disabled Daniel Borkmann
2024-12-16 17:24 ` Andrea Righi
2024-12-16 18:26 ` Eduard Zingerman
2024-12-16 18:33 ` Alexei Starovoitov
2024-12-16 20:28 ` Daniel Borkmann
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