From b64bf18e021f772c5a69ebf442cb63968d4a163c Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Tue, 3 Dec 2024 19:03:59 -0800 Subject: [PATCH] selftests/bpf: Expand coverage of preempt tests to sleepable kfunc For preemption-related kfuncs, we don't test their interaction with sleepable kfuncs (we do test helpers) even though the verifier has code to protect against such a pattern. Expand coverage of the selftest to include this case. Acked-by: Eduard Zingerman Signed-off-by: Kumar Kartikeya Dwivedi --- tools/testing/selftests/bpf/progs/preempt_lock.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/preempt_lock.c b/tools/testing/selftests/bpf/progs/preempt_lock.c index 5269571cf7b57d..6c5797bf0ead57 100644 --- a/tools/testing/selftests/bpf/progs/preempt_lock.c +++ b/tools/testing/selftests/bpf/progs/preempt_lock.c @@ -5,6 +5,8 @@ #include "bpf_misc.h" #include "bpf_experimental.h" +extern int bpf_copy_from_user_str(void *dst, u32 dst__sz, const void *unsafe_ptr__ign, u64 flags) __weak __ksym; + SEC("?tc") __failure __msg("BPF_EXIT instruction in main prog cannot be used inside bpf_preempt_disable-ed region") int preempt_lock_missing_1(struct __sk_buff *ctx) @@ -113,6 +115,18 @@ int preempt_sleepable_helper(void *ctx) return 0; } +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +__failure __msg("kernel func bpf_copy_from_user_str is sleepable within non-preemptible region") +int preempt_sleepable_kfunc(void *ctx) +{ + u32 data; + + bpf_preempt_disable(); + bpf_copy_from_user_str(&data, sizeof(data), NULL, 0); + bpf_preempt_enable(); + return 0; +} + int __noinline preempt_global_subprog(void) { preempt_balance_subprog();