[BUG REPORT] Deadlock and other reachable panic caused by lots of syscall fork

[Marsman1996]

描述错误/Describe the bug
There is a deadlock and several reachable panic when program calls syscall fork multiple times.

Deadlock at src/libs/rwlock.rs:260-262.

DragonOS/kernel/src/libs/rwlock.rs

Lines 260 to 262 in 72423f9

	match self.try_write() {
	Some(guard) => return guard,
	None => spin_loop(),

Panic at src/mm/allocator/slab.rs:44

DragonOS/kernel/src/mm/allocator/slab.rs

Lines 42 to 45 in 72423f9

	self.zone
	.allocate(layout)
	.expect("Should succeed after refill")
	.as_ptr()

and src/namespaces/pid_namespace.rs:113

DragonOS/kernel/src/namespaces/pid_namespace.rs

Lines 108 to 113 in 72423f9

	if tid == 0 {
	nr = pid_ns
	.id_alloctor
	.write()
	.alloc()
	.expect("PID allocation failed.");

请填写您的电脑的信息/Environment

• OS Version：Debian GNU/Linux 11
• DragonOS Version：72423f9
• DADK Version：dadk 0.2.0
• Rust Version：rustc 1.84.0-nightly (fbab78289 2024-11-04)

重现步骤/To Reproduce

1. Compile a program which calls system call fork multiple times

#include <unistd.h>

int main() {
  for (int i = 0; i < 1000; i++)
    fork();
}

2. Run the compiled program

期望行为/Expected behavior
DragonOS should not panic or fall into deadlock.

屏幕截图/Log
Scree log:

root@DragonOS:/$ /bin/deadlock
[ ERROR ] (src/debug/panic/mod.rs:15)	 Kernel Panic Occurred.
Location:
	File: src/mm/allocator/slab.rs
	Line: 44, Column: 22
Message:
	Should succeed after refill: OutOfMemory
Rust Panic Backtrace:
Current PCB:
	ProcessControlBlock { pid: Pid(9), tgid: Pid(9), thread_pid: RwLock { lock: 0, data: UnsafeCell { .. } }, basic: RwLock { lock: 0, data: U}
/bin/deadlock: Process terminated
root@DragonOS:/$ [ ERROR ] (src/debug/panic/mod.rs:15)	 Kernel Panic Occurred.
Location:
	File: src/mm/allocator/slab.rs
	Line: 44, Column: 22
Message:
	Should succeed aft[ ERROR ] (src/debug/panic/mod.rs:15)	 Kernel Panic Occurred.
Location:
	File: src/mm/allocator/slab.rs
	Line: 4[ ERROR ] (src/debug/panic/mod.rs:15)	 Kernel Panic Occur[ ERROR ] (src/debug/panic/mod.rs:15)	 Kernel Panic Occurred.
Location:
	File: src/namespaces/pid_namespace.rs
	Line: 113, Column: 22
Message:
	PID allocation failed.
Rust Panic Backtrace:
Current PCB:
	ProcessControlBlock { pid: Pid(4724), tgid: Pid(4724), thread_pid: RwLock { lock: 0, data: UnsafeCell { .. } }, basic: RwLock { lock: 0, d}

The GDB log:

(gdb) bt
#0  core::sync::atomic::AtomicUsize::fetch_update<fn(usize) -> core::option::Option<usize>> (self=0xffff800018a62800, 
    set_order=core::sync::atomic::Ordering::Acquire, fetch_order=core::sync::atomic::Ordering::Relaxed, f=<optimized out>)
    at /root/.rustup/toolchains/nightly-2024-11-05-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/sync/atomic.rs:2908
#1  alloc::sync::Weak<dragonos_kernel::process::ProcessControlBlock, alloc::alloc::Global>::upgrade<dragonos_kernel::process::ProcessControlBlock, alloc::alloc::Global> (self=<optimized out>) at /root/.rustup/toolchains/nightly-2024-11-05-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/sync.rs:3001
#2  dragonos_kernel::process::ProcessControlBlock::arch_current_pcb () at src/arch/x86_64/process/mod.rs:286
#3  dragonos_kernel::process::ProcessManager::current_pcb () at src/process/mod.rs:166
#4  0x0000000200000000 in ?? ()
#5  0x0000000000000000 in ?? ()
(gdb) n
dragonos_kernel::process::ProcessManager::current_pcb () at src/process/mod.rs:167
167         }
(gdb) 
dragonos_kernel::libs::rwlock::RwLock<ida::IdAllocator>::try_write<ida::IdAllocator> (self=0xffff80001eb35910) at src/libs/rwlock.rs:211
211             let r = self.inner_try_write();
(gdb) 
213                 ProcessManager::preempt_enable();
(gdb) 
216             return r;
(gdb) 
dragonos_kernel::libs::rwlock::RwLock<ida::IdAllocator>::write<ida::IdAllocator> (self=0xffff80001eb35910) at src/libs/rwlock.rs:260
260                 match self.try_write() {
(gdb) 
262                     None => spin_loop(),
(gdb) 
260                 match self.try_write() {
(gdb) 
262                     None => spin_loop(),
(gdb) bt
#0  dragonos_kernel::libs::rwlock::RwLock<ida::IdAllocator>::write<ida::IdAllocator> (self=0xffff80001eb35910) at src/libs/rwlock.rs:262
#1  dragonos_kernel::namespaces::pid_namespace::PidStrcut::alloc_pid (ns=..., set_tid=...) at src/namespaces/pid_namespace.rs:111
#2  0x0000000000000000 in ?? ()