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Kernel: Protect Thread::m_name with a spinlock

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This replaces manually grabbing the thread's main lock.

This lets us remove the `get_thread_name` and `set_thread_name` syscalls
from the big lock. :^)
This commit is contained in:
Sam Atkins 2023-02-04 14:11:35 +00:00 • committed by Andreas Kling
parent fe7b08dad7
commit 1014aefe64
5 changed files with 27 additions and 27 deletions
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24
Kernel/Syscalls/thread.cpp
View file

@ -180,7 +180,7 @@ ErrorOr<FlatPtr> Process::sys$kill_thread(pid_t tid, int signal)
ErrorOr<FlatPtr> Process::sys$set_thread_name(pid_t tid, Userspace<char const*> user_name, size_t user_name_length)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::stdio));
auto name = TRY(try_copy_kstring_from_user(user_name, user_name_length));
@ -199,7 +199,7 @@ ErrorOr<FlatPtr> Process::sys$set_thread_name(pid_t tid, Userspace<char const*>
ErrorOr<FlatPtr> Process::sys$get_thread_name(pid_t tid, Userspace<char*> buffer, size_t buffer_size)
{
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
VERIFY_NO_PROCESS_BIG_LOCK(this);
TRY(require_promise(Pledge::thread));
if (buffer_size == 0)
return EINVAL;
@ -208,19 +208,19 @@ ErrorOr<FlatPtr> Process::sys$get_thread_name(pid_t tid, Userspace<char*> buffer
if (!thread || thread->pid() != pid())
return ESRCH;
SpinlockLocker locker(thread->get_lock());
auto thread_name = thread->name();
TRY(thread->name().with([&](auto& thread_name) -> ErrorOr<void> {
if (thread_name->view().is_null()) {
char null_terminator = '\0';
TRY(copy_to_user(buffer, &null_terminator, sizeof(null_terminator)));
return {};
}
if (thread_name.is_null()) {
char null_terminator = '\0';
TRY(copy_to_user(buffer, &null_terminator, sizeof(null_terminator)));
return 0;
}
if (thread_name->length() + 1 > buffer_size)
return ENAMETOOLONG;
if (thread_name.length() + 1 > buffer_size)
return ENAMETOOLONG;
return copy_to_user(buffer, thread_name->characters(), thread_name->length() + 1);
}));
TRY(copy_to_user(buffer, thread_name.characters_without_null_termination(), thread_name.length() + 1));
return 0;
}