[Bug 1387594] Re: init: symbol lookup error: /lib/powerpc64le-linux-gnu/libnss_ldap.so.2: undefined symbol: __libc_lock_lock

[Louis Bouchard]

debdiff for the SRU on Trusty

** Description changed:

- This bug is specific to the PPC64EL architecture. More details in the
- analysis.
+ [SRU justification]
+ The version of the library in the archive for Utopic and Trusty has been built prior to a change in glibc that removes an expected symbol. Rebuild of the libnss-ldap library with the current source package will render the library unusable and may cause systems to become unbootable.
+ 
+ [Impact]
+ Without this fix, a rebuild of the libnss-ldap package will cause grave impact where usage of the libnss-ldap will segfault. Such a segfault during the boot process will cause the system to become unbootable.
+ 
+ [Fix]
+ Backport the glibc-2.16.patch that is now merged in Vivid into Utopic and Trusty. The version of the library in Precise already uses the correct glibc symbol.
+ 
+ [Test Case]
+ $ sudo apt-get download libnss-ldap
+ $ mkdir tmp
+ $ dpkg -x libnss-ldap_264-2.2ubuntu4_amd64.deb tmp
+ $ nm -D tmp/lib/x86_64-linux-gnu/libnss_ldap-2.15.so |grep lock$
+                  w __pthread_mutex_lock
+                  w __pthread_mutex_unlock
+ #Rebuild the library
+ $ pull-lp-source libnss-ldap trusty
+ $ sbuild -A -d trusty libnss-ldap_264-2.2ubuntu4.dsc
+ $ rm -Rf tmp/*
+ $ dpkg -x libnss-ldap_264-2.2ubuntu4_amd64.deb tmp
+ $ nm -D tmp/lib/x86_64-linux-gnu/libnss_ldap-2.19.so | grep lock$
+                  U __libc_lock_lock
+                  U __libc_lock_unlock
+ 
+ Notice that the libnss-ldap version change (2.15 -> 2.19). With the
+ newly built version, the expected _pthread_mutex_lock|unlock is no
+ longer present.
+ 
+ [Regression]
+ None expected. This is already present and in use in the upstream version of the library.
+ 
+ [Original Description of the problem]
+ 
+ Unlike previously thought, this bug is _NOT_ specific to the PPC64EL
+ architecture. More details in the analysis.
  
  Many commands that require the use of libnss-ldap will fail with
  Segmentation Fault. The boot procedure itself can be blocked with the
  following message.
  
  One potential workaround is to remove the use of ldap from the
  /etc/nsswitch.conf file to at least provide a bootable system.

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https://bugs.launchpad.net/bugs/1387594

Title:
  init: symbol lookup error: /lib/powerpc64le-linux-
  gnu/libnss_ldap.so.2: undefined symbol: __libc_lock_lock

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