perf header: Use write lock when translating BPF prog info pointers

write_bpf_prog_info() holds a read lock while temporarily mutating
info_linear via bpil_addr_to_offs()/bpil_offs_to_addr().  Between these
two calls, the pointers in info_linear contain file offsets instead of
heap addresses.  Concurrent readers holding the same read lock see the
file offsets and dereference them as pointers.

Use down_write()/up_write() instead of down_read()/up_read() to exclude
concurrent readers during the addr-to-offset-to-addr translation window.

Fixes: 63ac7968a1fb ("perf bpf: Save bpf_prog_info information as headers to perf.data")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

0 files changed, 0 insertions, 0 deletions