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* [Bug nscd/16878] New: nscd enters busy loop on long netgroup entry via nss_ldap of nslcd
@ 2014-04-28 16:22 siddhesh at redhat dot com
  2014-04-30  9:10 ` [Bug nscd/16878] " siddhesh at redhat dot com
                   ` (5 more replies)
  0 siblings, 6 replies; 7+ messages in thread
From: siddhesh at redhat dot com @ 2014-04-28 16:22 UTC (permalink / raw)
  To: glibc-bugs

https://sourceware.org/bugzilla/show_bug.cgi?id=16878

            Bug ID: 16878
           Summary: nscd enters busy loop on long netgroup entry via
                    nss_ldap of nslcd
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: nscd
          Assignee: siddhesh at redhat dot com
          Reporter: siddhesh at redhat dot com
                CC: drepper.fsp at gmail dot com

Description of problem:

If there's a long (>1024 bytes) netgroup entry retrieved via nslcd's nss_ldap,
nscd with netgroup caching enabled will enter a busy loop, hogging a CPU. Each
repetition causes another nscd thread to busy loop, consequently using up all
available CPU time.

This is because nss_ldap (correctly) returns NSS_STATUS_TRYAGAIN if the
provided buffer is not large enough to hold the result while nscd and the glibc
nss modules for netgroups expect and set NSS_STATUS_UNAVAIL respectively.

How reproducible:
always

Steps to Reproduce:
1. add long netgroup entry to LDAP
2. enable netgroup caching in nscd
3. getent netgroup longnetgroupentry

Actual results:
nscd thread enters busy loop, getent times out waiting for nscd and gets
netgroup data directly

Expected results:
nscd returns netgroup data

Patch coming up.

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^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2014-06-22  7:46 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-04-28 16:22 [Bug nscd/16878] New: nscd enters busy loop on long netgroup entry via nss_ldap of nslcd siddhesh at redhat dot com
2014-04-30  9:10 ` [Bug nscd/16878] " siddhesh at redhat dot com
2014-05-26  6:10 ` cvs-commit at gcc dot gnu.org
2014-05-26  6:11 ` siddhesh at redhat dot com
2014-06-12 19:32 ` fweimer at redhat dot com
2014-06-12 19:33 ` fweimer at redhat dot com
2014-06-22  7:46 ` cvs-commit at gcc dot gnu.org

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