| Message ID | 20200616050432.1902042-1-andriin@fb.com |
|---|---|
| State | Accepted |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | [bpf,1/2] bpf: bpf_probe_read_kernel_str() has to return amount of data read on success | expand |
On Mon, Jun 15, 2020 at 10:04:30PM -0700, 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> Looks good, thanks for fixing this up: Reviewed-by: Christoph Hellwig <hch@lst.de>
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>
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;
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(-)