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Commit 5541075a authored by Jiri Olsa's avatar Jiri Olsa Committed by Daniel Borkmann
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bpf: Prevent double bpf_prog_put call from bpf_tracing_prog_attach

The bpf_tracing_prog_attach error path calls bpf_prog_put
on prog, which causes refcount underflow when it's called
from link_create function.

  link_create
    prog = bpf_prog_get              <-- get
    ...
    tracing_bpf_link_attach(prog..
      bpf_tracing_prog_attach(prog..
        out_put_prog:
          bpf_prog_put(prog);        <-- put

    if (ret < 0)
      bpf_prog_put(prog);            <-- put

Removing bpf_prog_put call from bpf_tracing_prog_attach
and making sure its callers call it instead.

Fixes: 4a1e7c0c

 ("bpf: Support attaching freplace programs to multiple attach points")
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210111191650.1241578-1-jolsa@kernel.org
parent f97844f9
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