RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 08:18:11 +00:00
Code Issues Activity Actions

Kernel: Fix Lock race causing infinite spinning between two threads

Browse source 
We need to account for how many shared lock instances the current
thread owns, so that we can properly release such references when
yielding execution.

We also need to release the process lock when donating.
This commit is contained in:
Tom 2020-12-14 16:36:22 -07:00 • committed by Andreas Kling
parent 56701f91f9
commit c4176b0da1
10 changed files with 359 additions and 96 deletions
Download patch file Download diff file Expand all files Collapse all files

7
Kernel/Syscalls/sched.cpp
View file

@ -41,14 +41,11 @@ int Process::sys$donate(pid_t tid)
if (tid < 0)
return -EINVAL;
// We don't strictly need to grab the scheduler lock here, but it
// will close a race where we can find the thread but it disappears
// before we call Scheduler::donate_to.
ScopedSpinLock lock(g_scheduler_lock);
ScopedCritical critical;
auto thread = Thread::from_tid(tid);
if (!thread || thread->pid() != pid())
return -ESRCH;
Scheduler::donate_to(thread, "sys$donate");
Thread::current()->donate_without_holding_big_lock(thread, "sys$donate");
return 0;
}