tree d0652ffe5f06ae2854df33f54e66ce4244d53cff
parent 83a5ff403a2cd625832f01032c0feb8bf9c2a89e
author Willy Tarreau <w@1wt.eu> 1566389762 +0200
committer Willy Tarreau <w@1wt.eu> 1566391632 +0200
encoding latin1

MEDIUM: debug: make the thread dump code show Lua backtraces

When we dump a thread's state (show thread, panic) we don't know if
anything is happening in Lua, which can be problematic especially when
calling external functions. With this patch, the thread dump code can
now detect if we're running in a global Lua task (hlua_process_task),
or in a TCP or HTTP Lua service (task_run_applet and applet.fct ==
hlua_applet_tcp_fct or http_applet_http_fct), or a fetch/converter
from an analyser (s->hlua != NULL). In such situations, it's able to
append a formatted Lua backtrace of the Lua execution path with
function names, file names and line numbers.

Note that a shorter alternative could be to call "luaL_where(hlua->T,0)"
which only prints the current location, but it's not necessarily sufficient
for complex code.

(cherry picked from commit 78a7cb648ca33823c06430cedc6859ea7e7cd5df)
[wt: backported to improve troubleshooting when the watchdog fires]
Signed-off-by: Willy Tarreau <w@1wt.eu>