Bug 589014 – www-servers/nginx proxy crashing on ARM

• Product: Gentoo Linux
• Status: RESOLVED NEEDINFO

[Description Grobi 2016-07-17 17:37:56 UTC]

Nginx crashes on first request on ARM with compiler option PIE.
This issue occured on my Raspberry PI 2.
I saw no crashed since I disabled this flag only for nginx package and recompile nginx. (FIX: LDFLAGS="-fPIE -pie" CFLAGS="-fPIE -pie")
There should be a way to disable those flags in ebuild for ARM per default.

Description by gordonb3:
I did some further digging into the issue. Adding more verbosity to tcpdump I can see Nginx fetching the page from the backend server. The page size exceeds the ethernet packet size, so I'm seeing two data packets and all seems normal. When Nginx is supposed to pass the page on to the client I'm only seeing a 52 byte (N)ACK packet.

I did note this in the log though:
Code:	
2016/04/14 14:32:11 [alert] 11395#0: worker process 11402 exited on signal 11	

Apparently the Nginx worker dies somewhere between receiving the page from the backend server and passing it on to the client. I disabled the gzip feature in Nginx, but that didn't help.

I have to come back on something I stated in the opening post however. Crazy how time flies sometimes. The logging appears to have been useless because I was looking at the backend server. As it turns out I did in fact update Nginx from 1.9.6 to 1.9.10-r3 (and 1.9.13 since noticing the issue) after the last access logged by Nginx. Luckily I create binary packages for this system (armvtel) so I could reinstall that previous version, and tadaaa. The proxy is working again. So it would seem that an old issue has risen again.


Edit: confirmed. I did a rebuild of Nginx with the following command line and now the proxy also works with 1.9.13
Code:	
LDFLAGS="-fPIE -pie" CFLAGS="-fPIE -pie" emerge -v nginx	
Didn't want to investigate whether those were compiler flags or linker flags :oops:

For further info see:
https://forums.gentoo.org/viewtopic-t-1042446-start-0-postdays-0-postorder-asc-highlight-.html?sid=b88b8bbc0907477fd0d0147bdbdd8143

[Comment 1 Mike Gilbert 2016-07-18 00:48:23 UTC]

What version of nginx?

[Comment 2 Grobi 2016-07-18 07:34:59 UTC]

It is in the text:
At least for 1.9.10-r3 and 1.9.13.
1.9.6 seemed to be OK thou.

I personally switched to Gentoo in May-2016 and directly hit this problem with 1.10.0.

[Comment 3 Thomas Deutschmann (RETIRED) 2016-07-19 23:46:15 UTC]

Please re-test with =www-servers/nginx-1.11.2 which will land in a few ours in the repository. Also please enable the "debug" USE flag for that package. This will allow you to use

>  debug_connection <IP;

in nginx' "events" block in "/etc/nginx.conf" so you only log connections in debug mode from a specific client.

Once you hit the problem again please attach the debug log showing the problem to this bug and change status.

Thanks!