6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jiri Olsa jolsa@kernel.org
commit 4b7c05598a644782b8451e415bb56f31e5c9d3ee upstream.
With newly merged code the uprobe behaviour is slightly different and affects uprobe consumer test.
We no longer need to check if the uprobe object is still preserved after removing last uretprobe, because it stays as long as there's pending/installed uretprobe instance.
This allows to run uretprobe consumers registered 'after' uprobe was hit even if previous uretprobe got unregistered before being hit.
The uprobe object will be now removed after the last uprobe ref is released and in such case it's held by ri->uprobe (return instance) which is released after the uretprobe is hit.
Reported-by: Ihor Solodrai ihor.solodrai@pm.me Signed-off-by: Jiri Olsa jolsa@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Tested-by: Ihor Solodrai ihor.solodrai@pm.me Closes: https://lore.kernel.org/bpf/w6U8Z9fdhjnkSp2UaFaV1fGqJXvfLEtDKEUyGDkwmoruDJ_A... Signed-off-by: Alexei Starovoitov ast@kernel.org Cc: Alan Maguire alan.maguire@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-)
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c @@ -869,21 +869,14 @@ static void consumer_test(struct uprobe_ fmt = "prog 0/1: uprobe"; } else { /* - * uprobe return is tricky ;-) - * * to trigger uretprobe consumer, the uretprobe needs to be installed, * which means one of the 'return' uprobes was alive when probe was hit: * * idxs: 2/3 uprobe return in 'installed' mask - * - * in addition if 'after' state removes everything that was installed in - * 'before' state, then uprobe kernel object goes away and return uprobe - * is not installed and we won't hit it even if it's in 'after' state. */ unsigned long had_uretprobes = before & 0b1100; /* is uretprobe installed */ - unsigned long probe_preserved = before & after; /* did uprobe go away */
- if (had_uretprobes && probe_preserved && test_bit(idx, after)) + if (had_uretprobes && test_bit(idx, after)) val++; fmt = "idx 2/3: uretprobe"; }