X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/b0d623f7f2ae71ed96e60569f61f9a9a27016e80..c7d2c2c6ee645e10cbccdd01c6191873ec77239d:/osfmk/kern/exception.c diff --git a/osfmk/kern/exception.c b/osfmk/kern/exception.c index a3578e1a0..a47544027 100644 --- a/osfmk/kern/exception.c +++ b/osfmk/kern/exception.c @@ -56,8 +56,6 @@ /* */ -#include - #include #include #include @@ -86,22 +84,9 @@ #include #include #include +#include -#if MACH_KDB -#include -#endif /* MACH_KDB */ - -#if MACH_KDB - -#include - -#if iPSC386 || iPSC860 -boolean_t debug_user_with_kdb = TRUE; -#else -boolean_t debug_user_with_kdb = FALSE; -#endif - -#endif /* MACH_KDB */ +extern int panic_on_exception_triage; unsigned long c_thr_exc_raise = 0; unsigned long c_thr_exc_raise_state = 0; @@ -119,6 +104,12 @@ kern_return_t exception_deliver( struct exception_action *excp, lck_mtx_t *mutex); +static kern_return_t +check_exc_receiver_dependency( + exception_type_t exception, + struct exception_action *excp, + lck_mtx_t *mutex); + #ifdef MACH_BSD kern_return_t bsd_exception( exception_type_t exception, @@ -158,9 +149,22 @@ exception_deliver( * Save work if we are terminating. * Just go back to our AST handler. */ - if (!thread->active) + if (!thread->active && !thread->inspection) return KERN_SUCCESS; + /* + * If there are no exception actions defined for this entity, + * we can't deliver here. + */ + if (excp == NULL) + return KERN_FAILURE; + + assert(exception < EXC_TYPES_COUNT); + if (exception >= EXC_TYPES_COUNT) + return KERN_FAILURE; + + excp = &excp[exception]; + /* * Snapshot the exception action data under lock for consistency. * Hold a reference to the port over the exception_raise_* calls @@ -224,7 +228,7 @@ exception_deliver( state, state_cnt, state, &state_cnt); } - if (kr == MACH_MSG_SUCCESS) + if (kr == MACH_MSG_SUCCESS && exception != EXC_CORPSE_NOTIFY) kr = thread_setstatus(thread, flavor, (thread_state_t)state, state_cnt); @@ -285,7 +289,7 @@ exception_deliver( state, state_cnt, state, &state_cnt); } - if (kr == MACH_MSG_SUCCESS) + if (kr == MACH_MSG_SUCCESS && exception != EXC_CORPSE_NOTIFY) kr = thread_setstatus(thread, flavor, (thread_state_t)state, state_cnt); @@ -301,7 +305,43 @@ exception_deliver( } /* - * Routine: exception + * Routine: check_exc_receiver_dependency + * Purpose: + * Verify that the port destined for receiving this exception is not + * on the current task. This would cause hang in kernel for + * EXC_CRASH primarily. Note: If port is transferred + * between check and delivery then deadlock may happen. + * + * Conditions: + * Nothing locked and no resources held. + * Called from an exception context. + * Returns: + * KERN_SUCCESS if its ok to send exception message. + */ +kern_return_t +check_exc_receiver_dependency( + exception_type_t exception, + struct exception_action *excp, + lck_mtx_t *mutex) +{ + kern_return_t retval = KERN_SUCCESS; + + if (excp == NULL || exception != EXC_CRASH) + return retval; + + task_t task = current_task(); + lck_mtx_lock(mutex); + ipc_port_t xport = excp[exception].port; + if ( IP_VALID(xport) + && ip_active(xport) + && task->itk_space == xport->ip_receiver) + retval = KERN_FAILURE; + lck_mtx_unlock(mutex); + return retval; +} + +/* + * Routine: exception_triage * Purpose: * The current thread caught an exception. * We make an up-call to the thread's exception server. @@ -311,9 +351,9 @@ exception_deliver( * thread_exception_return and thread_kdb_return * are possible. * Returns: - * Doesn't return. + * KERN_SUCCESS if exception is handled by any of the handlers. */ -void +kern_return_t exception_triage( exception_type_t exception, mach_exception_data_t code, @@ -322,67 +362,66 @@ exception_triage( thread_t thread; task_t task; host_priv_t host_priv; - struct exception_action *excp; - lck_mtx_t *mutex; - kern_return_t kr; + lck_mtx_t *mutex; + kern_return_t kr = KERN_FAILURE; assert(exception != EXC_RPC_ALERT); - if (exception == KERN_SUCCESS) - panic("exception"); + /* + * If this behavior has been requested by the the kernel + * (due to the boot environment), we should panic if we + * enter this function. This is intended as a debugging + * aid; it should allow us to debug why we caught an + * exception in environments where debugging is especially + * difficult. + */ + if (panic_on_exception_triage) { + panic("called exception_triage when it was forbidden by the boot environment"); + } + + thread = current_thread(); /* * Try to raise the exception at the activation level. */ - thread = current_thread(); mutex = &thread->mutex; - excp = &thread->exc_actions[exception]; - kr = exception_deliver(thread, exception, code, codeCnt, excp, mutex); - if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) - goto out; + if (KERN_SUCCESS == check_exc_receiver_dependency(exception, thread->exc_actions, mutex)) + { + kr = exception_deliver(thread, exception, code, codeCnt, thread->exc_actions, mutex); + if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) + goto out; + } /* * Maybe the task level will handle it. */ task = current_task(); mutex = &task->lock; - excp = &task->exc_actions[exception]; - kr = exception_deliver(thread, exception, code, codeCnt, excp, mutex); - if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) - goto out; + if (KERN_SUCCESS == check_exc_receiver_dependency(exception, task->exc_actions, mutex)) + { + kr = exception_deliver(thread, exception, code, codeCnt, task->exc_actions, mutex); + if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) + goto out; + } /* * How about at the host level? */ host_priv = host_priv_self(); mutex = &host_priv->lock; - excp = &host_priv->exc_actions[exception]; - kr = exception_deliver(thread, exception, code, codeCnt, excp, mutex); - if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) - goto out; - - /* - * Nobody handled it, terminate the task. - */ - -#if MACH_KDB - if (debug_user_with_kdb) { - /* - * Debug the exception with kdb. - * If kdb handles the exception, - * then thread_kdb_return won't return. - */ - db_printf("No exception server, calling kdb...\n"); - thread_kdb_return(); + + if (KERN_SUCCESS == check_exc_receiver_dependency(exception, host_priv->exc_actions, mutex)) + { + kr = exception_deliver(thread, exception, code, codeCnt, host_priv->exc_actions, mutex); + if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) + goto out; } -#endif /* MACH_KDB */ - - (void) task_terminate(task); out: - if (exception != EXC_CRASH) + if ((exception != EXC_CRASH) && (exception != EXC_RESOURCE) && + (exception != EXC_GUARD) && (exception != EXC_CORPSE_NOTIFY)) thread_exception_return(); - return; + return kr; } kern_return_t @@ -392,7 +431,6 @@ bsd_exception( mach_msg_type_number_t codeCnt) { task_t task; - struct exception_action *excp; lck_mtx_t *mutex; thread_t self = current_thread(); kern_return_t kr; @@ -402,9 +440,8 @@ bsd_exception( */ task = current_task(); mutex = &task->lock; - excp = &task->exc_actions[exception]; - kr = exception_deliver(self, exception, code, codeCnt, excp, mutex); + kr = exception_deliver(self, exception, code, codeCnt, task->exc_actions, mutex); if (kr == KERN_SUCCESS || kr == MACH_RCV_PORT_DIED) return(KERN_SUCCESS); @@ -413,22 +450,23 @@ bsd_exception( /* - * Raise an EXC_CRASH exception on the dying task. + * Raise an exception on a task. * This should tell launchd to launch Crash Reporter for this task. */ -kern_return_t abnormal_exit_notify(mach_exception_data_type_t exccode, - mach_exception_data_type_t excsubcode) +kern_return_t task_exception_notify(exception_type_t exception, + mach_exception_data_type_t exccode, mach_exception_data_type_t excsubcode) { mach_exception_data_type_t code[EXCEPTION_CODE_MAX]; wait_interrupt_t wsave; + kern_return_t kr = KERN_SUCCESS; code[0] = exccode; code[1] = excsubcode; wsave = thread_interrupt_level(THREAD_UNINT); - exception_triage(EXC_CRASH, code, EXCEPTION_CODE_MAX); + kr = exception_triage(exception, code, EXCEPTION_CODE_MAX); (void) thread_interrupt_level(wsave); - return (KERN_SUCCESS); + return kr; } @@ -438,9 +476,7 @@ kern_return_t abnormal_exit_notify(mach_exception_data_type_t exccode, */ kern_return_t sys_perf_notify(thread_t thread, int pid) { - host_priv_t hostp; - struct exception_action *excp; ipc_port_t xport; wait_interrupt_t wsave; kern_return_t ret; @@ -451,8 +487,7 @@ kern_return_t sys_perf_notify(thread_t thread, int pid) code[1] = pid; /* Pass out the pid */ struct task *task = thread->task; - excp = &hostp->exc_actions[EXC_RPC_ALERT]; - xport = excp->port; + xport = hostp->exc_actions[EXC_RPC_ALERT].port; /* Make sure we're not catching our own exception */ if (!IP_VALID(xport) || @@ -468,7 +503,7 @@ kern_return_t sys_perf_notify(thread_t thread, int pid) EXC_RPC_ALERT, code, 2, - excp, + hostp->exc_actions, &hostp->lock); (void)thread_interrupt_level(wsave);