diff options
| author | Maria Matejka <mq@ucw.cz> | 2021-05-24 13:41:23 +0200 |
|---|---|---|
| committer | Maria Matejka <mq@ucw.cz> | 2021-11-22 19:05:43 +0100 |
| commit | df3264f51ff38c9366398564a9d342a26bc83f37 (patch) | |
| tree | 449ae9b631b57f867cc01dd4b6e8de63bbc30045 /sysdep | |
| parent | 1289c1c5eede5b3d015d06b725d30024ccac51bd (diff) | |
Lock position checking allows for safe lock unions
Diffstat (limited to 'sysdep')
| -rw-r--r-- | sysdep/unix/coroutine.c | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/sysdep/unix/coroutine.c b/sysdep/unix/coroutine.c index 71847505..2eba142c 100644 --- a/sysdep/unix/coroutine.c +++ b/sysdep/unix/coroutine.c @@ -44,26 +44,31 @@ * Locking subsystem */ +_Thread_local struct lock_order locking_stack = {}; +_Thread_local struct domain_generic **last_locked = NULL; + #define ASSERT_NO_LOCK ASSERT_DIE(last_locked == NULL) struct domain_generic { pthread_mutex_t mutex; + uint order; struct domain_generic **prev; struct lock_order *locked_by; const char *name; }; -#define DOMAIN_INIT(_name) { .mutex = PTHREAD_MUTEX_INITIALIZER, .name = _name } +#define DOMAIN_INIT(_name, _order) { .mutex = PTHREAD_MUTEX_INITIALIZER, .name = _name, .order = _order } -static struct domain_generic the_bird_domain_gen = DOMAIN_INIT("The BIRD"); +static struct domain_generic the_bird_domain_gen = DOMAIN_INIT("The BIRD", OFFSETOF(struct lock_order, the_bird)); DOMAIN(the_bird) the_bird_domain = { .the_bird = &the_bird_domain_gen }; struct domain_generic * -domain_new(const char *name) +domain_new(const char *name, uint order) { + ASSERT_DIE(order < sizeof(struct lock_order)); struct domain_generic *dg = xmalloc(sizeof(struct domain_generic)); - *dg = (struct domain_generic) DOMAIN_INIT(name); + *dg = (struct domain_generic) DOMAIN_INIT(name, order); return dg; } @@ -74,11 +79,11 @@ domain_free(struct domain_generic *dg) xfree(dg); } -_Thread_local struct lock_order locking_stack = {}; -_Thread_local struct domain_generic **last_locked = NULL; - void do_lock(struct domain_generic *dg, struct domain_generic **lsp) { + if ((char *) lsp - (char *) &locking_stack != dg->order) + bug("Trying to lock on bad position: order=%u, lsp=%p, base=%p", dg->order, lsp, &locking_stack); + if (lsp <= last_locked) bug("Trying to lock in a bad order"); if (*lsp) @@ -96,6 +101,9 @@ void do_lock(struct domain_generic *dg, struct domain_generic **lsp) void do_unlock(struct domain_generic *dg, struct domain_generic **lsp) { + if ((char *) lsp - (char *) &locking_stack != dg->order) + bug("Trying to unlock on bad position: order=%u, lsp=%p, base=%p", dg->order, lsp, &locking_stack); + if (dg->locked_by != &locking_stack) bug("Inconsistent domain state on unlock"); if ((last_locked != lsp) || (*lsp != dg)) |