Emacs Bug: file-remote-p 2014-05-15

now my emacs is fried.

◆ xah@xah-p6813w◆ 2014-05-15 17:30 ◆ ~/
◆ setsid emacs

◆ xah@xah-p6813w◆ 2014-05-15 17:30 ◆ ~/
◆
Backtrace:
emacs[0x50030b]
emacs[0x4e631d]
emacs[0x4feabe]
emacs[0x4feb23]
/lib/x86_64-linux-gnu/libpthread.so.0(+0xfcb0)[0x7f218c9c5cb0]
emacs[0x44334c]
emacs[0x448dea]
emacs[0x45cbed]
emacs[0x45f936]
emacs[0x557c2c]
emacs[0x42da1e]
emacs[0x42d9e4]
emacs[0x4498d5]
emacs[0x4f10e1]
emacs[0x4f2f74]
emacs[0x4f41aa]
emacs[0x557b02]
emacs[0x4e8a3e]
emacs[0x557a08]
emacs[0x4eadb7]
emacs[0x4eb0b2]
emacs[0x41524f]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xed)[0x7f218b61376d]
emacs[0x415d55]

This post is just a record for myself. Following are the details.

the version is

GNU Emacs 24.4.50.1 (x86_64-unknown-linux-gnu, GTK+ Version 2.24.10) of 2014-04-24 on xah-p6813w
ErgoEmacs distribution 2.0.0

(it's from emacs github mirror, i compiled myself on that date.)

here's what happened.

I have a elisp script that process 7 thousand html files.

(this https://github.com/xahlee/xahscripts/blob/master/make_download_copy/make_download_copy-find.el )

I run it regularly, few times a month. Today i noticed a bug. Basically, one of my function expect 2 args of position (aka point), but it got 2 nil. (due to a empty href value in html file).

the function call is this:

(xahsite-remove-ads (point-min) (point-max))

The calling function is “xah-remove-ads-in-file”.

the error message is this:

xah-remove-ads-in-file: Wrong type argument: integer-or-marker-p, nil

normally, when a function didn't get its args, it would simply cause the script to stop, that's all. But, apparently this caused emacs to semi-freeze and behave strangely. If i have toggle-debug-on-error on, emacs would freeze hard. And in another instance, i see this error:

file-remote-p: wrong type of argument

and this would be repeated few times per second forever, printed into messages buffer, semi-freeze emacs with cpu going up and fan kicks in. C-g doesn't stop it, nor Cx C-c. Seems the only way is killall emacs from terminal.

very strange. file-remote-p

after a few force quit, then when i start emacs, emacs crashes with some /lib/x86_64-linux-gnu/libpthread.so.0(+0xfcb0)[0x7f218c9c5cb0] error you see in the beginning of this post. (i think this is due to something in loading /home/xah/.emacs.d/.emacs.desktop (that's emacs's desktop-save, loading previous session stuff.))

if i start emacs with emacs --debug-init, emacs just freeze or crash

but anyway, i can get emacs to start by not loadin desktop.

i think this is reproducible. This code:

(xah-remove-ads-in-file
"/home/xah/web/xahlee_org/diklo/xahlee_info/comp/blog_past_2011-11.html"
"/home/xah/web/xahlee_info/comp/blog_past_2011-11.html"
"/home/xah/web/xahlee_info/"
)

where the first file is a html that contain this content:

<a href="">Screen Size Comparison: DVD, iPhone, iPad, MacBook, Blu-ray</a>

if you actually want to try, it's lightly complicated. All the 3 files should exist. The first 2 should be identical. You'll also need files from my emacs init on github, and also some of my packages in ErgoEmacs. I don't expect anyone to try to reproduce, this is just a log for myself.

i didn't have time to investigate. So, writing a log for now.