# Weird issues with nginx **URL:** \ **Category:** NGINX\ **Created:** [June 15, 2013, 3:33pm UTC](https://www.ruby-forum.com/t/weird-issues-with-nginx/235350 "2013-06-15T15:33:05Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\ **Post date:** [June 15, 2013, 3:33pm UTC](https://www.ruby-forum.com/t/weird-issues-with-nginx/235350/1 "2013-06-15T15:33:05Z")
Hello, I was trying to add rate limiting to our setup (mp4 file serving) and got into some very strange issues. First, with version 1.2.0, I was seeing the following: 2013/06/14 13:25:02 [emerg] 12470#0: \*147816 malloc(18446744073709551608) failed (12: Cannot allocate memory), client: 92.247.59.175, server: localhost, request: “GET /vid3/QkpnNF3f5RY0\_D9j0L8ovw/1371217700/12/46812/46812\_720x406\_500k.mp4 HTTP/1.1”, host: “vm0.xxxxxxx” The same happened with 1.2.7. I tried doing the same with 1.4.1, and what I got was a crash, with stuff like this: 2013/06/14 20:50:58 [alert] 1690#0: worker process 26026 exited on signal 6 2013/06/14 20:50:58 [alert] 1690#0: worker process 25973 exited on signal 11 2013/06/14 20:50:58 [alert] 1690#0: worker process 25976 exited on signal 11 and something like this, a bit cut: \*\*\* glibc detected \*\*\* nginx: worker process: free(): invalid next size (normal): 0x000000000199b900 \*\*\* ======= Backtrace: ========= /lib/x86\_64-linux-gnu/libc.so.6(+0x76d76)[0x7f4ea69fed76] /lib/x86\_64-linux-gnu/libc.so.6(cfree+0x6c)[0x7f4ea6a03aac] nginx: worker process[0x4059eb] nginx: worker process[0x43067b] Removing the ifs in the config fixes the problem, but that doesn’t help me 🙂 This is a compiled nginx from source, on debian stable (wheezy), with a few small additions available at [https://github.com/krokodilerian/trafstat/tree/master/nginx](https://github.com/krokodilerian/trafstat/tree/master/nginx) . Any ideas how to proceed with this, maybe adding a stack trace to find who does the offending malloc? I’ve looked at some google results, and some people have seen such insane mallocs (this one is -6 on a 64bit unsigned value), when trying to use a variable that wasn’t there, but that doesn’t seem to be my case. I have a debug log and other stuff I can send, if that would be helpful. Here’s my config, the file names look something like /data/v/63/27763/27763\_1920x1080\_4000k.mp4 : location /vid3/ { error\_log /usr/local/nginx/logs/debug.log debug; location ~ ^/vid3/(?[\w-=]+)/(?\w+)(?/[0-9/]+._[0-9]+x[0-9]+_)(?[0-9]+00)(?k.mp4)?(?.\*)$ { mp4; mp4\_buffer\_size 1m; mp4\_max\_buffer\_size 5m; ``` if ($invalid_referer) { return 403; } secure_link $rcvmd5,$linkexp; secure_link_md5 ``` “XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX$remote\_net$fnm$spd$kmp$linkexp” ; ``` if ($secure_link = "") { # invalid return 403; } if ($secure_link = "0") { # expired return 410; } if ($spd = 400 ) { limit_rate_after 400k; limit_rate 50k; } if ($spd = 500 ) { limit_rate_after 500k; limit_rate 50k; } if ($spd = 1000 ) { limit_rate_after 1600k; limit_rate 200k; } if ($spd = 4000 ) { limit_rate_after 3200k; limit_rate 400k; } alias /data/v$fnm$spd$kmp; } return 404; ``` } ---
**Author:** ![Vasil\_Kolev](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/ce7236/32.png) [@Vasil\_Kolev](https://www.ruby-forum.com/u/Vasil_Kolev)\ **Post date:** [June 15, 2013, 11:07pm UTC](https://www.ruby-forum.com/t/weird-issues-with-nginx/235350/2 "2013-06-15T23:07:33Z")
On Sat, Jun 15, 2013 at 04:32:04PM +0300, Vasil Kolev wrote: Hi there, > Removing the ifs in the config fixes the problem, but that doesn’t help > me 🙂 > > This is a compiled nginx from source, on debian stable (wheezy), with a > few small additions available at > [trafstat/nginx at master · krokodilerian/trafstat · GitHub](https://github.com/krokodilerian/trafstat/tree/master/nginx) . > > Any ideas how to proceed with this, The usual first step would be to see whether the problem persists when you just use the distributed nginx, with no external modules or patches. But in this case, that’s probably unnecessary, since you already know that without the “if” statements, no problems appear. You use “if” inside “location”, and you do something other than “return …” or “rewrite … last”. Under those circumstances, pretty much all bets are off (unless you can explain why your use is safe). See [GitHub - nginxinc/nginx-wiki: ARCHIVED -- Source for the now archived NGINX Wiki section of https://www.nginx.com · GitHub](http://wiki.nginx.org/IfIsEvil) for some more details. Perhaps using a “map” to set values to be used in limit\_rate and limit\_rate\_after directives would avoid the “if in location” problem? ## f Francis D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![Vasil\_Kolev](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/ce7236/32.png) [@Vasil\_Kolev](https://www.ruby-forum.com/u/Vasil_Kolev)\ **Post date:** [June 16, 2013, 12:02am UTC](https://www.ruby-forum.com/t/weird-issues-with-nginx/235350/3 "2013-06-16T00:02:28Z")
В 22:06 +0100 на 15.06.2013 (сб), Francis D. написа: > See [GitHub - nginxinc/nginx-wiki: ARCHIVED -- Source for the now archived NGINX Wiki section of https://www.nginx.com · GitHub](http://wiki.nginx.org/IfIsEvil) for some more details. > > Perhaps using a “map” to set values to be used in limit\_rate and > limit\_rate\_after directives would avoid the “if in location” problem? The limit\_rate directive doesn’t accept a variable as a parameter, otherwise that would’ve been easier. I might just copy the location 4 times with the speed hardcoded for each one, to get rid of the ifs, shouldn’t be too ugly. I’ll test this tomorrow. ---
**Author:** ![Vasil\_Kolev](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/ce7236/32.png) [@Vasil\_Kolev](https://www.ruby-forum.com/u/Vasil_Kolev)\ **Post date:** [June 16, 2013, 2:08am UTC](https://www.ruby-forum.com/t/weird-issues-with-nginx/235350/4 "2013-06-16T02:08:38Z")
On Sun, Jun 16, 2013 at 01:01:37AM +0300, Vasil Kolev wrote: > В 22:06 +0100 на 15.06.2013 (сб), Francis D. написа: > > But in this case, that’s probably unnecessary, since you already know > > that without the “if” statements, no problems appear. > > Perhaps using a “map” to set values to be used in limit\_rate and > > limit\_rate\_after directives would avoid the “if in location” problem? > The limit\_rate directive doesn’t accept a variable as a parameter, > otherwise that would’ve been easier. Ah, yes, you’re correct. $limit\_rate could help there, but there doesn’t seem to be an equivalent $limit\_rate\_after variable, so you’re still stuck. > I might just copy the location 4 > times with the speed hardcoded for each one, to get rid of the ifs, > shouldn’t be too ugly. That should work. A series of server-level ifs to set the directive values might also work – that may end up more maintainable, perhaps. Good luck with it, ## f Francis D. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![Vasil\_Kolev](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/v/ce7236/32.png) [@Vasil\_Kolev](https://www.ruby-forum.com/u/Vasil_Kolev)\ **Post date:** [June 16, 2013, 9:56pm UTC](https://www.ruby-forum.com/t/weird-issues-with-nginx/235350/5 "2013-06-16T21:56:47Z")
В 01:01 +0300 на 16.06.2013 (нд), Vasil Kolev написа: > > …" or “rewrite … last”. Under those circumstances, pretty much all > > otherwise that would’ve been easier. I might just copy the location 4 > > times with the speed hardcoded for each one, to get rid of the ifs, > > shouldn’t be too ugly. > > I’ll test this tomorrow. It definitely works this way. Is there anything that can be done to detect whenever the “if” is used in a dangerous way? Seems like a bad idea to be able to crash the webserver with a simple config.