Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Pull bpf fixes from Alexei Starovoitov:

 - Fix handling of BPF arena relocations (Andrii Nakryiko)

 - Fix race in bpf_arch_text_poke() on s390 (Ilya Leoshkevich)

 - Fix use of virt_to_phys() on arm64 when mmapping BTF (Lorenz Bauer)

 - Reject %p% format string in bprintf-like BPF helpers (Paul Chaignon)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  libbpf: Fix handling of BPF arena relocations
  btf: Fix virt_to_phys() on arm64 when mmapping BTF
  selftests/bpf: Stress test attaching a BPF prog to another BPF prog
  s390/bpf: Fix bpf_arch_text_poke() with new_addr == NULL again
  selftests/bpf: Add negative test cases for snprintf
  bpf: Reject %p% format string in bprintf-like helpers

1 files changed, 9 insertions, 1 deletions

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index c7f8313ba449..0c9a35782c83 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -566,7 +566,15 @@ static void bpf_jit_plt(struct bpf_plt *plt, void *ret, void *target)
 {
 	memcpy(plt, &bpf_plt, sizeof(*plt));
 	plt->ret = ret;
-	plt->target = target;
+	/*
+	 * (target == NULL) implies that the branch to this PLT entry was
+	 * patched and became a no-op. However, some CPU could have jumped
+	 * to this PLT entry before patching and may be still executing it.
+	 *
+	 * Since the intention in this case is to make the PLT entry a no-op,
+	 * make the target point to the return label instead of NULL.
+	 */
+	plt->target = target ?: ret;
 }
 
 /*