From: Arnd Bergmann <arnd@xxxxxxxx>
clang versions before version 18 manage to badly optimize the bpf
verifier, with lots of variable spills leading to excessive stack
usage in addition to likely rather slow code:
kernel/bpf/verifier.c:23936:5: error: stack frame size (2096) exceeds limit (1280) in 'bpf_check' [-Werror,-Wframe-larger-than]
kernel/bpf/verifier.c:21563:12: error: stack frame size (1984) exceeds limit (1280) in 'do_misc_fixups' [-Werror,-Wframe-larger-than]
Turn off the sanitizer in the two functions that suffer the most from
this when using one of the affected clang version.
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
kernel/bpf/verifier.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 2fa797a6d6a2..7724c7a56d79 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -19810,7 +19810,14 @@ static int do_check_insn(struct bpf_verifier_env *env, bool *do_print_state)
return 0;
}
-static int do_check(struct bpf_verifier_env *env)
+#if defined(CONFIG_CC_IS_CLANG) && CONFIG_CLANG_VERSION < 180100
+/* old clang versions cause excessive stack usage here */
+#define __workaround_kasan __disable_sanitizer_instrumentation
+#else
+#define __workaround_kasan
+#endif
+
+static __workaround_kasan int do_check(struct bpf_verifier_env *env)
{
bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
struct bpf_verifier_state *state = env->cur_state;
@@ -21817,7 +21824,7 @@ static int add_hidden_subprog(struct bpf_verifier_env *env, struct bpf_insn *pat
/* Do various post-verification rewrites in a single program pass.
* These rewrites simplify JIT and interpreter implementations.
*/
-static int do_misc_fixups(struct bpf_verifier_env *env)
+static __workaround_kasan int do_misc_fixups(struct bpf_verifier_env *env)
{
struct bpf_prog *prog = env->prog;
enum bpf_attach_type eatype = prog->expected_attach_type;
--
2.39.5
