From: Kumar Kartikeya Dwivedi <memxor@gmail.com> mainline inclusion from mainline-v6.9-rc1 commit 8be6a0147af314fd60db9da2158cd737dc6394a7 category: feature bugzilla: https://atomgit.com/openeuler/kernel/issues/8335 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ---------------------------------------------------------------------- Add selftests covering the following cases: - A static or global subprog called from within a RCU read section works - A static subprog taking an RCU read lock which is released in caller works - A static subprog releasing the caller's RCU read lock works Global subprogs that leave the lock in an imbalanced state will not work, as they are verified separately, so ensure those cases fail as well. Acked-by: Yonghong Song <yonghong.song@linux.dev> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Acked-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20240205055646.1112186-3-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- .../selftests/bpf/prog_tests/rcu_read_lock.c | 6 + .../selftests/bpf/progs/rcu_read_lock.c | 120 ++++++++++++++++++ 2 files changed, 126 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c b/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c index 3f1f58d3a729..a1f7e7378a64 100644 --- a/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c +++ b/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c @@ -29,6 +29,10 @@ static void test_success(void) bpf_program__set_autoload(skel->progs.non_sleepable_1, true); bpf_program__set_autoload(skel->progs.non_sleepable_2, true); bpf_program__set_autoload(skel->progs.task_trusted_non_rcuptr, true); + bpf_program__set_autoload(skel->progs.rcu_read_lock_subprog, true); + bpf_program__set_autoload(skel->progs.rcu_read_lock_global_subprog, true); + bpf_program__set_autoload(skel->progs.rcu_read_lock_subprog_lock, true); + bpf_program__set_autoload(skel->progs.rcu_read_lock_subprog_unlock, true); err = rcu_read_lock__load(skel); if (!ASSERT_OK(err, "skel_load")) goto out; @@ -75,6 +79,8 @@ static const char * const inproper_region_tests[] = { "inproper_sleepable_helper", "inproper_sleepable_kfunc", "nested_rcu_region", + "rcu_read_lock_global_subprog_lock", + "rcu_read_lock_global_subprog_unlock", }; static void test_inproper_region(void) diff --git a/tools/testing/selftests/bpf/progs/rcu_read_lock.c b/tools/testing/selftests/bpf/progs/rcu_read_lock.c index 14fb01437fb8..ab3a532b7dd6 100644 --- a/tools/testing/selftests/bpf/progs/rcu_read_lock.c +++ b/tools/testing/selftests/bpf/progs/rcu_read_lock.c @@ -319,3 +319,123 @@ int cross_rcu_region(void *ctx) bpf_rcu_read_unlock(); return 0; } + +__noinline +static int static_subprog(void *ctx) +{ + volatile int ret = 0; + + if (bpf_get_prandom_u32()) + return ret + 42; + return ret + bpf_get_prandom_u32(); +} + +__noinline +int global_subprog(u64 a) +{ + volatile int ret = a; + + return ret + static_subprog(NULL); +} + +__noinline +static int static_subprog_lock(void *ctx) +{ + volatile int ret = 0; + + bpf_rcu_read_lock(); + if (bpf_get_prandom_u32()) + return ret + 42; + return ret + bpf_get_prandom_u32(); +} + +__noinline +int global_subprog_lock(u64 a) +{ + volatile int ret = a; + + return ret + static_subprog_lock(NULL); +} + +__noinline +static int static_subprog_unlock(void *ctx) +{ + volatile int ret = 0; + + bpf_rcu_read_unlock(); + if (bpf_get_prandom_u32()) + return ret + 42; + return ret + bpf_get_prandom_u32(); +} + +__noinline +int global_subprog_unlock(u64 a) +{ + volatile int ret = a; + + return ret + static_subprog_unlock(NULL); +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int rcu_read_lock_subprog(void *ctx) +{ + volatile int ret = 0; + + bpf_rcu_read_lock(); + if (bpf_get_prandom_u32()) + ret += static_subprog(ctx); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int rcu_read_lock_global_subprog(void *ctx) +{ + volatile int ret = 0; + + bpf_rcu_read_lock(); + if (bpf_get_prandom_u32()) + ret += global_subprog(ret); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int rcu_read_lock_subprog_lock(void *ctx) +{ + volatile int ret = 0; + + ret += static_subprog_lock(ctx); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int rcu_read_lock_global_subprog_lock(void *ctx) +{ + volatile int ret = 0; + + ret += global_subprog_lock(ret); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int rcu_read_lock_subprog_unlock(void *ctx) +{ + volatile int ret = 0; + + bpf_rcu_read_lock(); + ret += static_subprog_unlock(ctx); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int rcu_read_lock_global_subprog_unlock(void *ctx) +{ + volatile int ret = 0; + + bpf_rcu_read_lock(); + ret += global_subprog_unlock(ret); + return 0; +} -- 2.34.1