Worker process exited on signal 7

[Maxim Dounin]

Hello!

On Mon, Jan 10, 2011 at 01:38:53PM +0100, Balazs Pocze wrote:

> 2011/1/7 Maxim Dounin <mdounin at mdounin.ru>:
> > Hello!
> >
> > On Fri, Jan 07, 2011 at 10:35:31AM +0100, Balazs Pocze wrote:
> >
> >> Hello everyone,
> >>
> >> I started to use nginx insted of lighttpd for a few days ago. It
> >> serves only static content (thumbnail pictures) and performs well, but
> >> yesterday it stopped working, and I got the following messages on the
> >> error.log.
> >>
> >> 2011/01/06 17:54:30 [alert] 7542#0: worker process 31959 exited on signal 7
> >>
> >> I didn't found anything about this error message on the net.
> >
> > It looks like signal 7 on linux x86 is SIGBUS (oh, linux has
> > architecture-dependant signal numbers... really intresting design
> > decision).
> >
> > It usually generated on an attempt to access memory which doesn't
> > exists, and may be generated on various hardware problems as well.
> > Under linux this includes uncorrectable memory errors as seen via
> > MCA and problems reading pages after page fault (e.g. swap disk
> > died, or mmap'ed file read failed).
> >
> Maybe yes. But I have no proof, and the problem is that: with lighttpd
> i don't have this errors. So I don't know what to think about it.

This may be hardware-related error.  No errors in lighttpd may 
indicate it's lucky (in case of memory errors) or using other 
system interfaces (in case of paging-related problems).

> >> The error
> >> logging level is "crit" because I don't have enough storage to keep
> >> all the "file not found" errors :) (The logging goes to a tmpfs
> >> partiton).
> >
> > Just a side note: you may want to use "log_not_found off;" instead.
> >
> It is not a good sollution for me, because I need the 404 errors. (for
> fact, on this server I _only_ need the 404 errors to get (re)generated
> the thumbnail pictures, I don't need these errors on error log, just
> in access.log (and a feature will be welcome, if I can direct the 404
> logs into one log file, and 200's to an another.)

"log_not_found off;" does exactly what you need - it just disables 
logging "file not found" errors to error_log.

> >> So I restarted the lighttpd on that server, and it works now, so I
> >> didn't think that it is a hardware error.
> >> Here is th the output of nginx -V:
> >>
> >> nginx version: nginx/0.8.54
> >> built by gcc 4.3.3 (Ubuntu 4.3.3-5ubuntu4)
> >> TLS SNI support enabled
> >> configure arguments: --prefix=/opt/nginx
> >> --error-log-path=var/log/error.log --http-log-path=var/log/access.log
> >> --http-client-body-temp-path=/opt/nginx/var/cache/client_body_temp
> >> --http-proxy-temp-path=/opt/nginx/var/cache/proxy_temp
> >> --http-fastcgi-temp-path=/opt/nginx/var/cache/fastcgi_temp
> >> --without-http_uwsgi_module --without-http_scgi_module
> >> --with-http_ssl_module --with-openssl=../openssl-0.9.8k
> >> --user=www-data --group=www-data --pid-
> >> path=/opt/nginx/var/run/nginx.pid
> >> --conf-path=/opt/nginx/etc/nginx.conf --with-http_stub_status_module
> >>
> >> It is a x86_64 system.
> >>
> >> At this machine the www data files are on two SSD-s, and one of those
> >> SSD-s are bad, bacause not all 'secors' (hey what is the correct term
> >> for sectors on SSD?) can be read. Can it cause this type of error?
> >
> > Obviously it can if you also have swap on these disks and/or read
> > files via mmap().  While nginx doesn't use mmap() to read files,
> > something like may be used internally by OS for e.g. sendfile(),
> > not sure.
> >
> > This may also be a problem in nginx which causes it to access
> > nonexisting memory regions.
> >
> > To further debug the problem it should be helpful to obtain
> > coredump and backtrace, as well as show full config.  See
> > http://wiki.nginx.org/Debugging for basic instructions.
> >
> there's no swap space on this machine.

It's impossible to tell anything without further info.  Please 
follow provided instructions to obtain coredump.

Maxim Dounin