diff --git a/scripts/qemugdb/coroutine.py b/scripts/qemugdb/coroutine.py index 20f76ed37b..e98fc48a4b 100644 --- a/scripts/qemugdb/coroutine.py +++ b/scripts/qemugdb/coroutine.py @@ -46,9 +46,60 @@ def get_jmpbuf_regs(jmpbuf): 'r15': jmpbuf[JB_R15], 'rip': glibc_ptr_demangle(jmpbuf[JB_PC], pointer_guard) } -def bt_jmpbuf(jmpbuf): - '''Backtrace a jmpbuf''' - regs = get_jmpbuf_regs(jmpbuf) +def symbol_lookup(addr): + # Example: "__clone3 + 44 in section .text of /lib64/libc.so.6" + result = gdb.execute(f"info symbol {hex(addr)}", to_string=True).strip() + try: + if "+" in result: + (func, result) = result.split(" + ") + (offset, result) = result.split(" in ") + else: + offset = "0" + (func, result) = result.split(" in ") + func_str = f"{func}<+{offset}> ()" + except: + return f"??? ({result})" + + # Example: Line 321 of "../util/coroutine-ucontext.c" starts at address + # 0x55cf3894d993 and ends at 0x55cf3894d9ab + # . + result = gdb.execute(f"info line *{hex(addr)}", to_string=True).strip() + if not result.startswith("Line "): + return func_str + result = result[5:] + + try: + result = result.split(" starts ")[0] + (line, path) = result.split(" of ") + path = path.replace("\"", "") + except: + return func_str + + return f"{func_str} at {path}:{line}" + +def dump_backtrace(regs): + ''' + Backtrace dump with raw registers, mimic GDB command 'bt'. + ''' + # Here only rbp and rip that matter.. + rbp = regs['rbp'] + rip = regs['rip'] + i = 0 + + while rbp: + # For all return addresses on stack, we want to look up symbol/line + # on the CALL command, because the return address is the next + # instruction instead of the CALL. Here -1 would work for any + # sized CALL instruction. + print(f"#{i} {hex(rip)} in {symbol_lookup(rip if i == 0 else rip-1)}") + rip = gdb.parse_and_eval(f"*(uint64_t *)(uint64_t)({hex(rbp)} + 8)") + rbp = gdb.parse_and_eval(f"*(uint64_t *)(uint64_t)({hex(rbp)})") + i += 1 + +def dump_backtrace_live(regs): + ''' + Backtrace dump with gdb's 'bt' command, only usable in a live session. + ''' old = dict() # remember current stack frame and select the topmost @@ -69,6 +120,17 @@ def bt_jmpbuf(jmpbuf): selected_frame.select() +def bt_jmpbuf(jmpbuf): + '''Backtrace a jmpbuf''' + regs = get_jmpbuf_regs(jmpbuf) + try: + # This reuses gdb's "bt" command, which can be slightly prettier + # but only works with live sessions. + dump_backtrace_live(regs) + except: + # If above doesn't work, fallback to poor man's unwind + dump_backtrace(regs) + def co_cast(co): return co.cast(gdb.lookup_type('CoroutineUContext').pointer()) @@ -101,10 +163,15 @@ class CoroutineBt(gdb.Command): gdb.execute("bt") - if gdb.parse_and_eval("qemu_in_coroutine()") == False: - return + try: + # This only works with a live session + co_ptr = gdb.parse_and_eval("qemu_coroutine_self()") + except: + # Fallback to use hard-coded ucontext vars if it's coredump + co_ptr = gdb.parse_and_eval("co_tls_current") - co_ptr = gdb.parse_and_eval("qemu_coroutine_self()") + if co_ptr == False: + return while True: co = co_cast(co_ptr)