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Kernel: Fix race in clock_nanosleep

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This is a complete fix of clock_nanosleep, because the thread holds the
process lock again when returning from sleep()/sleep_until().
Therefore, no further concurrent invalidation can occur.
This commit is contained in:
Ben Wiederhake 2020-03-03 05:12:39 +01:00 • committed by Andreas Kling
parent 28e1da344d
commit 4dd4dd2f3c
1 changed files with 7 additions and 0 deletions
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7
Kernel/Process.cpp
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@ -4290,6 +4290,13 @@ int Process::sys$clock_nanosleep(const Syscall::SC_clock_nanosleep_params* user_
if (wakeup_time > g_uptime) { if (wakeup_time > g_uptime) {
u32 ticks_left = wakeup_time - g_uptime; u32 ticks_left = wakeup_time - g_uptime;
if (!is_absolute && params.remaining_sleep) { if (!is_absolute && params.remaining_sleep) {
if (!validate_write_typed(params.remaining_sleep)) {
// This can happen because the lock is dropped while
// sleeping, thus giving other threads the opportunity
// to make the region unwritable.
return -EFAULT;
}
timespec remaining_sleep; timespec remaining_sleep;
memset(&remaining_sleep, 0, sizeof(timespec)); memset(&remaining_sleep, 0, sizeof(timespec));
remaining_sleep.tv_sec = ticks_left / TICKS_PER_SECOND; remaining_sleep.tv_sec = ticks_left / TICKS_PER_SECOND;