| 2014-07-24 19:29:34 |
Rafael David Tinoco |
description |
I'm running trusty on a bunch of machines, doing frequent dist-upgrades. My hosts have gcc-multilib installed.
Yesterday, I noticed that initramfs generation was hanging. Today I investigated further and found out that what was hanging were the calls to /libx32/ld-linux-x32.so.2.
This is triggered in initramfs generation because there are at some hooks that incorrectly use copy_exec to copy shell scripts into the initramfs image. In a working machine, when ldd encounters a shell script, it will first call the 64bit linker and since it fails, it will then call the 32bit linker which will also fail.
However, in a machine affected by this bug, the second call will hang forever, preventing new image generation, and package updates in general, when this happens as a trigger for update-initramfs.
Originally I thought this was related to the kernel version, since I was unable to reproduce in a freshly installed machine running -22 and was reproducing it in a machine running -20, but now I'm also reproducing it in a machine running -22, so it must be something else.
I'm sorry I can't provide the exact cause right now, but I think it's worth noting that in some situation there might be a problem, and try to find out which those situations are.
I now have one host running 3.13.0-22-generic, with libc6-x32=2.19-0ubuntu3, where doing ldd /usr/bin/ldd hangs, and another host, with the exact same kernel and libc6-x32 version where doing ldd /usr/bin/ldd produces the expected error message (not a dynamic executable). The main difference is that the first one was installed yesterday and the second one was installed today. Both are dist-upgraded to the latest version of everything. |
SRU Justification:
Impact: Calls to /libx32/ld-linux-x32.so.2 hang when using auditd
Fix: Upstream, a3c54931199565930d6d84f4c3456f6440aefd41
Testcase: Comment #7
Old Description:
I'm running trusty on a bunch of machines, doing frequent dist-upgrades. My hosts have gcc-multilib installed.
Yesterday, I noticed that initramfs generation was hanging. Today I investigated further and found out that what was hanging were the calls to /libx32/ld-linux-x32.so.2.
This is triggered in initramfs generation because there are at some hooks that incorrectly use copy_exec to copy shell scripts into the initramfs image. In a working machine, when ldd encounters a shell script, it will first call the 64bit linker and since it fails, it will then call the 32bit linker which will also fail.
However, in a machine affected by this bug, the second call will hang forever, preventing new image generation, and package updates in general, when this happens as a trigger for update-initramfs.
Originally I thought this was related to the kernel version, since I was unable to reproduce in a freshly installed machine running -22 and was reproducing it in a machine running -20, but now I'm also reproducing it in a machine running -22, so it must be something else.
I'm sorry I can't provide the exact cause right now, but I think it's worth noting that in some situation there might be a problem, and try to find out which those situations are.
I now have one host running 3.13.0-22-generic, with libc6-x32=2.19-0ubuntu3, where doing ldd /usr/bin/ldd hangs, and another host, with the exact same kernel and libc6-x32 version where doing ldd /usr/bin/ldd produces the expected error message (not a dynamic executable). The main difference is that the first one was installed yesterday and the second one was installed today. Both are dist-upgraded to the latest version of everything. |
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