Qemu hangs after execute instruction "mret" in start

[yodalee]

I encounter following issued on my computer, and I have no clue how to solve it or what the problem is.
Here is my environment:

• Linux kernel: 5.12.12-arch1-1
• Compiler: riscv64-unknown-elf-gcc (Arch User Repository) 9.2.0
• qemu-system-riscv64: QEMU emulator version 6.0.0
• gdb: GNU gdb (GDB) 10.2

The problem is that, my breakpoint does not work in main function. I can step to the line asm volatile("mret"); in function start.
However, the debugger just hangs after this instruction, it does not hit my breakpoint set on main function. I can send interrupt by press Ctrl+C, it seems that sometimes it will stop in function timervec.
I think the timer interrupt is worked as expected.
Have no clue what the problem is and how to fix it. Does anyone face same issue?

[yodalee]

I just found that, the problem is caused by qemu v6. I switch to qemu v5.2 and I can break at main function now.