[Bug libc/685] New: NPTL causes random application crashes

["davidm at hpl dot hp dot com" <sourceware-bugzilla at sources dot redhat dot com>]

Several of us noticed that evolution on Debian/unstable sometimes crashes early
during program startup.  It turns out that the crash is due to memory
corruption.  In one particular case, the memory that got corrupted was in the
address range:

 0x2000000002daff10-0x2000000002daff1f

which happened to hold the function descriptors for shared library linkage stubs
("jump slots").  Of relevance was that the thread-pointer (r13) had the value:

 0x2000000002db0500

The corruption was caused by any NPTL routine trying to access the
thread-descriptor, since NPTL uses a "struct pthread" of size 1680 bytes (0x690).

I believe the problem is due to the fact that /lib/ld-linux-ia64.so.2 was built
for Linux Threads, which uses a thread descriptor size of 0x500.  Note that
sysdeps/generic/dl-tls.c has several references to TLS_PRE_TCB_SIZE for the case
where TLS_DTV_AT_TP is defined.  In other words, ld.so ends up having a
dependency on the size of the thread-descriptor.  Sure enough, if I invoke
evolution like this:

  /lib/tls/ld-linux-ia64.so.2 evolution

it works just fine.

My understanding is that /lib/ld-linux-ia64.so.2 should work for both NPTL and
LinuxThreads libraries and the dependency on the size of the thread-descriptor
is accidental.

I believe this same bug may affect Alpha, PowerPC, and SH.

For Alpha, I found this bug report, which sounds potentially related:

  http://sources.redhat.com/bugzilla/show_bug.cgi?id=299

-- 
           Summary: NPTL causes random application crashes
           Product: glibc
           Version: 2.3.2
            Status: NEW
          Severity: critical
          Priority: P1
         Component: libc
        AssignedTo: gotom at debian dot or dot jp
        ReportedBy: davidm at hpl dot hp dot com
                CC: glibc-bugs at sources dot redhat dot com
 GCC build triplet: ia64-linux
  GCC host triplet: ia64-linux
GCC target triplet: ia64-linux


http://sources.redhat.com/bugzilla/show_bug.cgi?id=685

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