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Fix some paging related bugs exposed by the spawn stress test.

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- Process::exec() needs to restore the original paging scope when called
  on a non-current process.
- Add missing InterruptDisabler guards around g_processes access.
- Only flush the TLB when modifying the active page tables.
This commit is contained in:
Andreas Kling 2018-11-09 01:25:31 +01:00
parent 7b96218389
commit e71cb1c56b
13 changed files with 110 additions and 67 deletions
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55
Kernel/Process.cpp
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@ -271,8 +271,11 @@ Process* Process::fork(RegisterDump& regs)
ProcFileSystem::the().addProcess(*child);
g_processes->prepend(child);
system.nprocess++;
{
InterruptDisabler disabler;
g_processes->prepend(child);
system.nprocess++;
}
#ifdef TASK_DEBUG
kprintf("Process %u (%s) forked from %u @ %p\n", child->pid(), child->name().characters(), m_pid, child->m_tss.eip);
#endif
@ -315,10 +318,12 @@ int Process::exec(const String& path, Vector<String>&& arguments, Vector<String>
dword entry_eip = 0;
PageDirectory* old_page_directory = m_page_directory;
PageDirectory* new_page_directory = reinterpret_cast<PageDirectory*>(kmalloc_page_aligned(sizeof(PageDirectory)));
dbgprintf("Process exec: PD=%x created\n", new_page_directory);
#ifdef MM_DEBUG
dbgprintf("Process %u exec: PD=%x created\n", pid(), new_page_directory);
#endif
MM.populate_page_directory(*new_page_directory);
m_page_directory = new_page_directory;
MM.enter_process_paging_scope(*this);
ProcessPagingScope paging_scope(*this);
// FIXME: Should we consider doing on-demand paging here? Is it actually useful?
bool success = region->page_in(*new_page_directory);
@ -400,10 +405,9 @@ int Process::exec(const String& path, Vector<String>&& arguments, Vector<String>
} // Ready to yield-teleport!
if (current == this) {
bool success = Scheduler::yield();
Scheduler::yield();
ASSERT_NOT_REACHED();
}
return 0;
}
@ -509,8 +513,11 @@ Process* Process::create_user_process(const String& path, uid_t uid, gid_t gid,
ProcFileSystem::the().addProcess(*process);
g_processes->prepend(process);
system.nprocess++;
{
InterruptDisabler disabler;
g_processes->prepend(process);
system.nprocess++;
}
#ifdef TASK_DEBUG
kprintf("Process %u (%s) spawned @ %p\n", process->pid(), process->name().characters(), process->m_tss.eip);
#endif
@ -562,9 +569,11 @@ Process* Process::create_kernel_process(void (*e)(), String&& name)
process->m_tss.eip = (dword)e;
if (process->pid() != 0) {
InterruptDisabler disabler;
g_processes->prepend(process);
system.nprocess++;
{
InterruptDisabler disabler;
g_processes->prepend(process);
system.nprocess++;
}
ProcFileSystem::the().addProcess(*process);
#ifdef TASK_DEBUG
kprintf("Kernel process %u (%s) spawned @ %p\n", process->pid(), process->name().characters(), process->m_tss.eip);
@ -603,7 +612,9 @@ Process::Process(String&& name, uid_t uid, gid_t gid, pid_t ppid, RingLevel ring
}
m_page_directory = (PageDirectory*)kmalloc_page_aligned(sizeof(PageDirectory));
dbgprintf("Process ctor: PD=%x created\n", m_page_directory);
#ifdef MM_DEBUG
dbgprintf("Process %u ctor: PD=%x created\n", pid(), m_page_directory);
#endif
MM.populate_page_directory(*m_page_directory);
if (fork_parent) {
@ -1246,15 +1257,13 @@ mode_t Process::sys$umask(mode_t mask)
return old_mask;
}
void Process::reap(pid_t pid)
void Process::reap(Process& process)
{
InterruptDisabler disabler;
auto* process = Process::from_pid(pid);
ASSERT(process);
dbgprintf("reap: %s(%u) {%s}\n", process->name().characters(), process->pid(), toString(process->state()));
ASSERT(process->state() == Dead);
g_processes->remove(process);
delete process;
dbgprintf("reap: %s(%u) {%s}\n", process.name().characters(), process.pid(), toString(process.state()));
ASSERT(process.state() == Dead);
g_processes->remove(&process);
delete &process;
}
pid_t Process::sys$waitpid(pid_t waitee, int* wstatus, int options)
@ -1273,7 +1282,13 @@ pid_t Process::sys$waitpid(pid_t waitee, int* wstatus, int options)
sched_yield();
if (m_was_interrupted_while_blocked)
return -EINTR;
reap(waitee);
Process* waitee_process;
{
InterruptDisabler disabler;
waitee_process = Process::from_pid(waitee);
}
ASSERT(waitee_process);
reap(*waitee_process);
if (wstatus)
*wstatus = m_waitee_status;
return m_waitee;