From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
<daniel@iogearbox.net>
Cc: <andrii@kernel.org>, <kernel-team@fb.com>,
Martin KaFai Lau <kafai@fb.com>
Subject: [PATCH v2 bpf-next 1/7] bpf: fix bpf_put_raw_tracepoint()'s use of __module_address()
Date: Mon, 30 Nov 2020 16:31:31 -0800 [thread overview]
Message-ID: <20201201003137.1692914-2-andrii@kernel.org> (raw)
In-Reply-To: <20201201003137.1692914-1-andrii@kernel.org>
__module_address() needs to be called with preemption disabled or with
module_mutex taken. preempt_disable() is enough for read-only uses, which is
what this fix does. Also, module_put() does internal check for NULL, so drop
it as well.
Fixes: a38d1107f937 ("bpf: support raw tracepoints in modules")
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
kernel/trace/bpf_trace.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index d255bc9b2bfa..23a390aac524 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2060,10 +2060,12 @@ struct bpf_raw_event_map *bpf_get_raw_tracepoint(const char *name)
void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp)
{
- struct module *mod = __module_address((unsigned long)btp);
+ struct module *mod;
- if (mod)
- module_put(mod);
+ preempt_disable();
+ mod = __module_address((unsigned long)btp);
+ module_put(mod);
+ preempt_enable();
}
static __always_inline
--
2.24.1
next prev parent reply other threads:[~2020-12-01 0:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 0:31 [PATCH v2 bpf-next 0/7] libbpf: add support for kernel module BTF CO-RE relocations Andrii Nakryiko
2020-12-01 0:31 ` Andrii Nakryiko [this message]
2020-12-01 0:31 ` [PATCH v2 bpf-next 2/7] libbpf: add internal helper to load BTF data by FD Andrii Nakryiko
2020-12-01 0:31 ` [PATCH v2 bpf-next 3/7] libbpf: refactor CO-RE relocs to not assume a single BTF object Andrii Nakryiko
2020-12-01 0:31 ` [PATCH v2 bpf-next 4/7] libbpf: add kernel module BTF support for CO-RE relocations Andrii Nakryiko
2020-12-01 0:31 ` [PATCH v2 bpf-next 5/7] selftests/bpf: add bpf_testmod kernel module for testing Andrii Nakryiko
2020-12-01 0:31 ` [PATCH v2 bpf-next 6/7] selftests/bpf: add support for marking sub-tests as skipped Andrii Nakryiko
2020-12-01 0:31 ` [PATCH v2 bpf-next 7/7] selftests/bpf: add CO-RE relocs selftest relying on kernel module BTF Andrii Nakryiko
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