From: John Fastabend <john.fastabend@gmail.com>
To: Andrii Nakryiko <andriin@fb.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org, ast@fb.com,
daniel@iogearbox.net
Cc: andrii.nakryiko@gmail.com, kernel-team@fb.com,
Andrii Nakryiko <andriin@fb.com>, Christoph Hellwig <hch@lst.de>
Subject: RE: [PATCH bpf 1/2] bpf: bpf_probe_read_kernel_str() has to return amount of data read on success
Date: Tue, 16 Jun 2020 00:01:22 -0700 [thread overview]
Message-ID: <5ee86e42810c7_4be02ab1b668a5b430@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <20200616050432.1902042-1-andriin@fb.com>
Andrii Nakryiko wrote:
> During recent refactorings, bpf_probe_read_kernel_str() started returning 0 on
> success, instead of amount of data successfully read. This majorly breaks
> applications relying on bpf_probe_read_kernel_str() and bpf_probe_read_str()
> and their results. Fix this by returning actual number of bytes read.
>
> Cc: Christoph Hellwig <hch@lst.de>
> Fixes: 8d92db5c04d1 ("bpf: rework the compat kernel probe handling")
> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> ---
> kernel/trace/bpf_trace.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index e729c9e587a0..a3ac7de98baa 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -241,7 +241,7 @@ bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr)
> if (unlikely(ret < 0))
> goto fail;
>
> - return 0;
> + return ret;
> fail:
> memset(dst, 0, size);
> return ret;
> --
> 2.24.1
>
Acked-by: John Fastabend <john.fastabend@gmail.com>
prev parent reply other threads:[~2020-06-16 7:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-16 5:04 [PATCH bpf 1/2] bpf: bpf_probe_read_kernel_str() has to return amount of data read on success Andrii Nakryiko
2020-06-16 5:04 ` [PATCH bpf 2/2] selftests/bpf: add variable-length data concatenation pattern test Andrii Nakryiko
2020-06-16 20:21 ` Daniel Borkmann
2020-06-16 21:27 ` Andrii Nakryiko
2020-06-16 22:23 ` Daniel Borkmann
2020-06-16 23:14 ` Andrii Nakryiko
2020-06-17 15:51 ` Daniel Borkmann
2020-06-18 19:09 ` John Fastabend
2020-06-18 21:59 ` Andrii Nakryiko
2020-06-18 23:48 ` John Fastabend
2020-06-19 0:09 ` Andrii Nakryiko
2020-06-16 6:54 ` [PATCH bpf 1/2] bpf: bpf_probe_read_kernel_str() has to return amount of data read on success Christoph Hellwig
2020-06-16 7:01 ` John Fastabend [this message]
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