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authorAndrii Nakryiko <andriin@fb.com>2020-06-15 22:04:30 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2020-06-17 17:50:02 +0200
commit02553b91da5deb63c8562b47529b09b734659af0 (patch)
tree82b0bdb70f7daa8660d243a98a1e893b4b08767c
parent6903cdae9f9f08d61e49c16cbef11c293e33a615 (diff)
bpf: bpf_probe_read_kernel_str() has to return amount of data read on success
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. Fixes: 8d92db5c04d1 ("bpf: rework the compat kernel probe handling") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200616050432.1902042-1-andriin@fb.com
-rw-r--r--kernel/trace/bpf_trace.c2
1 files changed, 1 insertions, 1 deletions
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;