Begin reporting may_goto timeouts to BPF program's stderr stream.
Acked-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
---
kernel/bpf/core.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index ab8b3446570c..47dcc4f19050 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -3168,6 +3168,22 @@ u64 __weak arch_bpf_timed_may_goto(void)
return 0;
}
+static noinline void bpf_prog_report_may_goto_violation(void)
+{
+#ifdef CONFIG_BPF_SYSCALL
+ struct bpf_stream_stage ss;
+ struct bpf_prog *prog;
+
+ prog = bpf_prog_find_from_stack();
+ if (!prog)
+ return;
+ bpf_stream_stage(ss, prog, BPF_STDERR, ({
+ bpf_stream_printk(ss, "ERROR: Timeout detected for may_goto instruction\n");
+ bpf_stream_dump_stack(ss);
+ }));
+#endif
+}
+
u64 bpf_check_timed_may_goto(struct bpf_timed_may_goto *p)
{
u64 time = ktime_get_mono_fast_ns();
@@ -3178,8 +3194,10 @@ u64 bpf_check_timed_may_goto(struct bpf_timed_may_goto *p)
return BPF_MAX_TIMED_LOOPS;
}
/* Check if we've exhausted our time slice, and zero count. */
- if (time - p->timestamp >= (NSEC_PER_SEC / 4))
+ if (unlikely(time - p->timestamp >= (NSEC_PER_SEC / 4))) {
+ bpf_prog_report_may_goto_violation();
return 0;
+ }
/* Refresh the count for the stack frame. */
return BPF_MAX_TIMED_LOOPS;
}
--
2.47.1
