From c82f9759b49fa1cfdcf799bdfeab98832423f0ca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Gr=C3=A9goire?= <loic@gregoire.dev>
Date: Sat, 2 May 2026 12:14:45 -0400
Subject: [PATCH] feat(ke/panic): add panic lock

---
 src/kern/amd64/int.zig | 1 +
 src/kern/panic.zig     | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/kern/amd64/int.zig b/src/kern/amd64/int.zig
index 3c06bec..329f6bc 100644
--- a/src/kern/amd64/int.zig
+++ b/src/kern/amd64/int.zig
@@ -48,6 +48,7 @@ export fn isr_handler_main(frame: *const amd64.IrqFrame) callconv(.{ .x86_64_sys
     const ipl = ke.ipl.set_hardware(.Device);
 
     if (frame.intno < 32) {
+        ki.panic.panic_lock.acquire_no_ipl();
         std.log.err("Unhandled exception: 0x{x} ({s}), err=0x{x}, pc=0x{x}", .{ frame.intno, exception_msg[frame.intno], frame.errcode, frame.rip });
         std.log.err("RAX=0x{x:0>16} RBX=0x{x:0>16} RCX=0x{x:0>16} RDX=0x{x:0>16}", .{ frame.rax, frame.rbx, frame.rcx, frame.rdx });
         std.log.err("RSI=0x{x:0>16} RDI=0x{x:0>16} RBP=0x{x:0>16} RSP=0x{x:0>16}", .{ frame.rsi, frame.rdi, frame.rbp, frame.rsp });
diff --git a/src/kern/panic.zig b/src/kern/panic.zig
index 1250110..d52050d 100644
--- a/src/kern/panic.zig
+++ b/src/kern/panic.zig
@@ -70,14 +70,18 @@ fn walk_stack_frame(base: usize) void {
     }
 }
 
+pub var panic_lock: ke.SpinLock = .init();
+
 pub fn panic_with_frame(
     msg: []const u8,
     frame: usize,
 ) noreturn {
-    std.log.err("KERNEL PANIC: {s}", .{msg});
+    std.log.err("KERNEL PANIC: {s} on CPU {}, curthread is {*}", .{ msg, ke.cpu.current(), ki.sched.percpu.local().current_thread.? });
     std.log.err("Stack trace:", .{});
     walk_stack_frame(frame);
 
+    panic_lock.release_no_ipl();
+
     while (true) {}
 }
 
@@ -88,5 +92,6 @@ pub fn panic(
     if (config.arch == .um) {
         std.debug.defaultPanic(msg, first_trace_addr);
     }
+    panic_lock.acquire_no_ipl();
     panic_with_frame(msg, @frameAddress());
 }