ebpf: add fallback when bpf(2) fails

commit 9306457 was too eager to use the same fallback with a log, and that could fail for other reasons (e.g. not enough buffer space). Add a fallback without using the log, so that on kernels older than 5.11 we have better chance of success. Closes: containers#1400 Signed-off-by: Giuseppe Scrivano <[email protected]>
giuseppe · Jan 30, 2024 · 983b400 · 983b400
1 parent 8b611f2
commit 983b400
Showing 1 changed file with 6 additions and 3 deletions.
diff --git a/src/libcrun/ebpf.c b/src/libcrun/ebpf.c
@@ -496,12 +496,15 @@ libcrun_ebpf_load (struct bpf_program *program, int dirfd, const char *pin, libc
   fd = bpf (BPF_PROG_LOAD, &attr, sizeof (attr));
   if (fd < 0)
     {
-      const size_t log_size = 8192;
-      cleanup_free char *log = xmalloc (log_size);
-
       /* Prior to Linux 5.11, eBPF programs were accounted to the memlock
          prlimit.  Attempt to bump the limit, if possible.  */
       bump_memlock ();
+      fd = bpf (BPF_PROG_LOAD, &attr, sizeof (attr));
+    }
+  if (fd < 0)
+    {
+      const size_t log_size = 8192;
+      cleanup_free char *log = xmalloc (log_size);
 
       log[0] = '\0';
       attr.log_level = 1;