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nova: lock pager object state during fault lookup

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Fixes #2950
This commit is contained in:
Alexander Boettcher 2018-09-03 22:18:34 +02:00 committed by Norman Feske
parent f01464ef9e
commit bc9f0fdc34
2 changed files with 26 additions and 17 deletions
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2
repos/base-nova/src/core/include/pager.h
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@ -306,8 +306,6 @@ namespace Genode {
*/
void unresolved_page_fault_occurred()
{
Lock::Guard _state_lock_guard(_state_lock);
_state.thread.unresolved_page_fault = true;
}

41
repos/base-nova/src/core/pager.cc
View File

@ -121,6 +121,20 @@ void Pager_object::_page_fault_handler(addr_t pager_obj)
if (utcb->msg_words() == 1)
_invoke_handler(pager_obj);
/*
* obj->pager() (pager thread) may issue a signal to the remote region
* handler thread which may respond via wake_up() (ep thread) before
* we are done here - we have to lock the whole page lookup procedure
*/
obj->_state_lock.lock();
obj->_state.thread.ip = ipc_pager.fault_ip();
obj->_state.thread.sp = 0;
obj->_state.thread.trapno = PT_SEL_PAGE_FAULT;
obj->_state.block();
obj->_state.block_pause_sm();
/* lookup fault address and decide what to do */
int error = obj->pager(ipc_pager);
@ -135,30 +149,25 @@ void Pager_object::_page_fault_handler(addr_t pager_obj)
/* dst pd has not enough kernel quota ? - try to recover */
if (ipc_pager.syscall_result() == Nova::NOVA_PD_OOM) {
uint8_t res = obj->handle_oom();
if (res == Nova::NOVA_PD_OOM)
if (res == Nova::NOVA_PD_OOM) {
obj->_state.unblock_pause_sm();
obj->_state.unblock();
obj->_state_lock.unlock();
/* block until revoke is due */
ipc_pager.reply_and_wait_for_fault(obj->sel_sm_block_oom());
else if (res == Nova::NOVA_OK)
} else if (res == Nova::NOVA_OK)
/* succeeded to recover - continue normally */
error = 0;
}
}
/* good case - found a valid region which is mappable */
if (!error)
if (!error) {
obj->_state.unblock_pause_sm();
obj->_state.unblock();
obj->_state_lock.unlock();
ipc_pager.reply_and_wait_for_fault();
obj->_state_lock.lock();
obj->_state.thread.ip = ipc_pager.fault_ip();
obj->_state.thread.sp = 0;
obj->_state.thread.trapno = PT_SEL_PAGE_FAULT;
obj->_state.block();
obj->_state.block_pause_sm();
obj->_state_lock.unlock();
}
const char * client_thread = obj->client_thread();
const char * client_pd = obj->client_pd();
@ -173,6 +182,8 @@ void Pager_object::_page_fault_handler(addr_t pager_obj)
/* region manager fault - to be handled */
log("page fault, ", fault_info, " reason=", error);
obj->_state_lock.unlock();
/* block the faulting thread until region manager is done */
ipc_pager.reply_and_wait_for_fault(obj->sel_sm_block_pause());
}