Bug #256157 “nscd crashed with SIGSEGV in start_thread()” : Bugs : glibc package : Ubuntu

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Daniel J Blueman (danielblueman) wrote on 2008-08-08:

#1

CoreDump.gz Edit (42.7 KiB, application/x-gzip)
Disassembly.txt Edit (605 bytes, text/plain; charset="utf-8")
ProcMaps.txt Edit (4.6 KiB, text/plain; charset="utf-8")
ProcStatus.txt Edit (730 bytes, text/plain; charset="utf-8")
Registers.txt Edit (911 bytes, text/plain; charset="utf-8")
Stacktrace.txt Edit (310 bytes, text/plain; charset="utf-8")
ThreadStacktrace.txt Edit (2.5 KiB, text/plain; charset="utf-8")

Revision history for this message

Apport retracing service (apport) wrote on 2008-08-08: Symbolic stack trace

#2

Stacktrace.txt (retraced) Edit (310 bytes, text/plain)

StacktraceTop:?? () from /usr/sbin/nscd
?? () from /usr/sbin/nscd
?? () from /usr/sbin/nscd
start_thread () from /lib/libpthread.so.0
clone () from /lib/libc.so.6

Revision history for this message

Apport retracing service (apport) wrote on 2008-08-08: Symbolic threaded stack trace

#3

ThreadStacktrace.txt (retraced) Edit (2.5 KiB, text/plain)

Revision history for this message

Daniel J Blueman (danielblueman) wrote on 2008-11-22:

#4

Download full text (18.0 KiB)

Having traced this a number of times, I have consistently seen this assertion fail:

nscd: mem.c:335: gc: Assertion `off_alloc <= db->head->first_free' failed.

This occurs during garbage collection, when the code is calculating slack space in it's tree layout:

ref_t off_alloc = (byte * BITS + cnt) * BLOCK_ALIGN;
assert (off_alloc <= db->head->first_free);

...it detects an overlap. This always fires after a new thread has been created:

# valgrind --trace-children=yes /usr/sbin/nscd -d
==7565== Memcheck, a memory error detector.
==7565== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al.
==7565== Using LibVEX rev 1854, a library for dynamic binary translation.
==7565== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP.
==7565== Using valgrind-3.3.1-Debian, a dynamic binary instrumentation framework.
==7565== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al.
==7565== For more details, rerun with: -v
==7565==
7565: handle_request: request received (Version = 2) from PID 7063
7565: GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 7586
7565: GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 7600
7565: GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 7603
7565: GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 7651
7565: GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 7651
7565: GETFDHST
7565: handle_request: request received (Version = 2) from PID 7651
7565: GETHOSTBYNAME (sony)
7565: Reloading "root" in password cache!
7565: Reloading "gdm" in password cache!
7565: Reloading "haldaemon" in password cache!
7565: Reloading "messagebus" in password cache!
7565: Reloading "polkituser" in password cache!
7565: Reloading "daniel" in password cache!
7565: Reloading "sshd" in password cache!
7565: Reloading "ntp" in password cache!
7565: Reloading "nobody" in password cache!
7565: Reloading "7" in password cache!
7565: Reloading "1" in password cache!
7565: Reloading "110" in password cache!
7565: Reloading "115" in password cache!
7565: Reloading "root" in password cache!
7565: Reloading "gdm" in password cache!
7565: Reloading "haldaemon" in password cache!
7565: Reloading "messagebus" in password cache!
7565: Reloading "polkituser" in password cache!
7565: Reloading "daniel" in password cache!
7565: Reloading "sshd" in password cache!
7565: Reloading "ntp" in password cache!
7565: Reloading "nobody" in password cache!
7565: Reloading "7" in password cache!
7565: Reloading "1" in password cache!
7565: Reloading "110" in password cache!
7565: Reloading "115" in password cache!
7565: Reloading "root" in password cache!
7565: Reloading "gdm" in password cache!
7565: Reloading "haldaemon" in password cache!
7565: Reloading "messagebus" in password cache!
7565: Reloading "polkituser" in password cache!
7565: Reloading "daniel" in password cache!
7565: Reloading "sshd" in password cache!
7565: Reload...

Having traced this a number of times, I have consistently seen this assertion fail:

nscd: mem.c:335: gc: Assertion `off_alloc <= db->head->first_free' failed.

This occurs during garbage collection, when the code is calculating slack space in it's tree layout:

ref_t off_alloc = (byte * BITS + cnt) * BLOCK_ALIGN;
      assert (off_alloc <= db->head->first_free);

...it detects an overlap. This always fires after a new thread has been created:

# valgrind --trace-children=yes /usr/sbin/nscd -d
==7565== Memcheck, a memory error detector.
==7565== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al.
==7565== Using LibVEX rev 1854, a library for dynamic binary translation.
==7565== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP.
==7565== Using valgrind-3.3.1-Debian, a dynamic binary instrumentation framework.
==7565== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al.
==7565== For more details, rerun with: -v
==7565== 
7565: handle_request: request received (Version = 2) from PID 7063
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 7586
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 7600
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 7603
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 7651
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 7651
7565: 	GETFDHST
7565: handle_request: request received (Version = 2) from PID 7651
7565: 	GETHOSTBYNAME (sony)
7565: Reloading "root" in password cache!
7565: Reloading "gdm" in password cache!
7565: Reloading "haldaemon" in password cache!
7565: Reloading "messagebus" in password cache!
7565: Reloading "polkituser" in password cache!
7565: Reloading "daniel" in password cache!
7565: Reloading "sshd" in password cache!
7565: Reloading "ntp" in password cache!
7565: Reloading "nobody" in password cache!
7565: Reloading "7" in password cache!
7565: Reloading "1" in password cache!
7565: Reloading "110" in password cache!
7565: Reloading "115" in password cache!
7565: Reloading "root" in password cache!
7565: Reloading "gdm" in password cache!
7565: Reloading "haldaemon" in password cache!
7565: Reloading "messagebus" in password cache!
7565: Reloading "polkituser" in password cache!
7565: Reloading "daniel" in password cache!
7565: Reloading "sshd" in password cache!
7565: Reloading "ntp" in password cache!
7565: Reloading "nobody" in password cache!
7565: Reloading "7" in password cache!
7565: Reloading "1" in password cache!
7565: Reloading "110" in password cache!
7565: Reloading "115" in password cache!
7565: Reloading "root" in password cache!
7565: Reloading "gdm" in password cache!
7565: Reloading "haldaemon" in password cache!
7565: Reloading "messagebus" in password cache!
7565: Reloading "polkituser" in password cache!
7565: Reloading "daniel" in password cache!
7565: Reloading "sshd" in password cache!
7565: Reloading "ntp" in password cache!
7565: handle_request: request received (Version = 2) from PID 8717
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8720
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8721
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8721
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8722
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8722
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8723
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8723
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8724
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8724
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8725
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8725
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8726
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8726
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8727
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8727
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8728
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8728
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8729
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8729
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8730
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8730
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8731
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8731
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8732
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8732
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8733
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8733
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8734
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8734
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8735
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8735
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8736
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8736
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8737
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8737
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8738
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8738
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8739
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8739
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8740
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8740
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8741
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8741
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8742
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8742
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8743
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8743
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8744
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8744
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8745
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8745
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8746
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8746
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8747
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8747
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8748
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8748
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8749
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8749
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8750
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8750
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8751
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8751
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8752
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8752
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8753
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8753
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8754
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8754
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8755
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8755
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8756
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8756
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8757
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8757
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8758
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8758
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: handle_request: request received (Version = 2) from PID 8759
7565: 	GETFDGR
7565: provide access to FD 6, for group
7565: handle_request: request received (Version = 2) from PID 8759
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: Reloading "nobody" in password cache!
7565: Reloading "7" in password cache!
7565: Reloading "1" in password cache!
7565: Reloading "110" in password cache!
7565: Reloading "115" in password cache!
7565: Reloading "root" in password cache!
7565: Reloading "gdm" in password cache!
7565: Reloading "haldaemon" in password cache!
7565: Reloading "messagebus" in password cache!
7565: Reloading "polkituser" in password cache!
7565: Reloading "daniel" in password cache!
7565: Reloading "sshd" in password cache!
7565: Reloading "ntp" in password cache!
7565: Reloading "nobody" in password cache!
7565: Reloading "7" in password cache!
7565: Reloading "1" in password cache!
7565: Reloading "110" in password cache!
7565: Reloading "115" in password cache!
7565: handle_request: request received (Version = 2) from PID 9337
7565: 	GETFDPW
7565: provide access to FD 4, for passwd
7565: Reloading "root" in password cache!
7565: Reloading "gdm" in password cache!
7565: Reloading "haldaemon" in password cache!
7565: Reloading "messagebus" in password cache!
7565: Reloading "polkituser" in password cache!
7565: Reloading "daniel" in password cache!
7565: Reloading "sshd" in password cache!
7565: Reloading "ntp" in password cache!
7565: Reloading "nobody" in password cache!
7565: Reloading "7" in password cache!
7565: Reloading "1" in password cache!
7565: Reloading "110" in password cache!
7565: Reloading "115" in password cache!
7565: Reloading "audio" in group cache!
7565: Reloading "root" in group cache!
7565: Reloading "gdm" in group cache!
7565: Reloading "gdm" in group cache!
7565: Reloading "haldaemon" in group cache!
7565: Reloading "haldaemon" in group cache!
7565: Reloading "120" in group cache!
7565: Reloading "104" in group cache!
7565: Reloading "30" in group cache!
7565: Reloading "123" in group cache!
7565: Reloading "20" in group cache!
7565: Reloading "4" in group cache!
7565: Reloading "125" in group cache!
7565: Reloading "44" in group cache!
7565: Reloading "108" in group cache!
7565: Reloading "127" in group cache!
7565: Reloading "24" in group cache!
7565: Reloading "daniel" in group cache!
7565: Reloading "46" in group cache!
7565: Reloading "25" in group cache!
7565: Reloading "100" in group cache!
7565: Reloading "0" in group cache!
7565: Reloading "tty" in group cache!
7565: remove GETPWBYUID entry "0"
7565: remove GETPWBYUID entry "111"
7565: remove GETPWBYNAME entry "root"
7565: remove GETPWBYUID entry "105"
7565: remove GETPWBYNAME entry "gdm"
7565: remove GETPWBYNAME entry "haldaemon"
7565: remove GETPWBYNAME entry "messagebus"
7565: remove GETPWBYUID entry "108"
7565: remove GETPWBYNAME entry "polkituser"
7565: remove GETPWBYUID entry "1500"
7565: remove GETPWBYUID entry "109"
7565: remove GETPWBYNAME entry "daniel"
==7565== Thread 2:
==7565== Conditional jump or move depends on uninitialised value(s)
==7565==    at 0x108A0: (within /usr/sbin/nscd)
==7565==    by 0xFBBD: (within /usr/sbin/nscd)
==7565==    by 0x5D56: (within /usr/sbin/nscd)
==7565==    by 0x484F50E: start_thread (in /lib/tls/i686/cmov/libpthread-2.8.90.so)
==7565==    by 0x495C7ED: clone (in /lib/tls/i686/cmov/libc-2.8.90.so)
7565: Reloading "nogroup" in group cache!
7565: handle_request: request received (Version = 2) from PID 6756
7565: 	GETPWBYNAME (daniel)
7565: Haven't found "daniel" in password cache!
7565: remove GETPWBYNAME entry "sshd"
7565: remove GETPWBYNAME entry "ntp"
7565: remove GETPWBYUID entry "116"
7565: remove GETPWBYUID entry "117"
==7565== 
==7565== Conditional jump or move depends on uninitialised value(s)
==7565==    at 0x10A10: (within /usr/sbin/nscd)
==7565==    by 0xFBBD: (within /usr/sbin/nscd)
==7565==    by 0x5D56: (within /usr/sbin/nscd)
==7565==    by 0x484F50E: start_thread (in /lib/tls/i686/cmov/libpthread-2.8.90.so)
==7565==    by 0x495C7ED: clone (in /lib/tls/i686/cmov/libc-2.8.90.so)
==7565== 
==7565== Conditional jump or move depends on uninitialised value(s)
==7565==    at 0x10B90: (within /usr/sbin/nscd)
==7565==    by 0xFBBD: (within /usr/sbin/nscd)
==7565==    by 0x5D56: (within /usr/sbin/nscd)
==7565==    by 0x484F50E: start_thread (in /lib/tls/i686/cmov/libpthread-2.8.90.so)
==7565==    by 0x495C7ED: clone (in /lib/tls/i686/cmov/libc-2.8.90.so)
==7565== 
==7565== Conditional jump or move depends on uninitialised value(s)
==7565==    at 0x10BD2: (within /usr/sbin/nscd)
==7565==    by 0xFBBD: (within /usr/sbin/nscd)
==7565==    by 0x5D56: (within /usr/sbin/nscd)
==7565==    by 0x484F50E: start_thread (in /lib/tls/i686/cmov/libpthread-2.8.90.so)
==7565==    by 0x495C7ED: clone (in /lib/tls/i686/cmov/libc-2.8.90.so)
nscd: mem.c:335: gc: Assertion `off_alloc <= db->head->first_free' failed.
==7565== 
==7565== ERROR SUMMARY: 8 errors from 4 contexts (suppressed: 40 from 2)
==7565== malloc/free: in use at exit: 13,620 bytes in 40 blocks.
==7565== malloc/free: 2,135 allocs, 2,095 frees, 182,826 bytes allocated.
==7565== For counts of detected errors, rerun with: -v
==7565== searching for pointers to 40 not-freed blocks.
==7565== checked 8,151,852 bytes.
==7565== 
==7565== LEAK SUMMARY:
==7565==    definitely lost: 444 bytes in 31 blocks.
==7565==      possibly lost: 1,008 bytes in 7 blocks.
==7565==    still reachable: 12,168 bytes in 2 blocks.
==7565==         suppressed: 0 bytes in 0 blocks.
==7565== Rerun with --leak-check=full to see details of leaked memory.
Killed

Changed in glibc:
status:	New → Confirmed

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Daniel J Blueman (danielblueman) wrote on 2008-11-22:

#5

This patch in Fedora 9 looks like the fix, by Ulrich:

2008-06-11 Ulrich Drepper <email address hidden>
* nscd/mem.c (gc): Initialize obstack earlier so that if we jump
out we don't use uninitialized memory.

http://cvs.fedoraproject.org/viewvc/rpms/glibc/F-9/glibc-nscd.patch?view=co

I'll try and isolate the specific fix, which will make an SRU easier.

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Daniel J Blueman (danielblueman) wrote on 2008-11-22:

#6

Various fixes have been made to the garbage collector in mem.c:

http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=history;f=nscd/mem.c;h=e821729dab3575c698129243951b91d3a1e55d18;hb=HEAD

This patch includes the various fixes which the current Intrepid nscd's garbage collector doesn't have:

http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=blobdiff;f=nscd/mem.c;h=e821729dab3575c698129243951b91d3a1e55d18;hp=21f2ae821dcb62d248e0ab9958779ab49564e78c;hb=HEAD;hpb=563574c13dfd9bb1069761d7ca5ccf65f1dae6c9

Thus, this is what needs patching in. Is anyone able to help?

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Daniel J Blueman (danielblueman) wrote on 2009-01-17:

#7

debdiff backporting fixes, tested on i686 and amd64 Edit (5.9 KiB, text/plain)

I backported Ulrich Drepper's (glibc maintainer) upstream nscd fixes, and have been testing them for a week.

I've attached my debdiff with this, confirming problem resolution on i686 and amd64 on Ubuntu 9.10.

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Daniel J Blueman (danielblueman) wrote on 2009-01-17:

#8

debdiff fix attached

Changed in glibc:
status:	Confirmed → Fix Committed

Revision history for this message

Daniel J Blueman (danielblueman) wrote on 2009-01-17:

#9

I have verified this bug is fixed in jaunty in glibc-2.9; I marked this bug-report as 'fix-committed', since I've attached the tested fix - perhaps this isn't the right state?

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Chris Coulson (chrisccoulson) wrote on 2009-01-17:

#10

Daniel has confirmed via e-mail that this bug is fixed in Jaunty, so setting to Fix Released.

Changed in glibc:
status:	Fix Committed → Fix Released

Revision history for this message

Daniel J Blueman (danielblueman) wrote on 2009-01-17:

#11

SRU justification:

impact:
1. in use, nscd can frequently crash, thus denying caching, leading to higher network load and latency on lookups
-> therefore high impact in a NFS and/or multi-user environment
2. user may experience notification that nscd has crashed, compromising desktop experience

resolution:
-> backported Ulrich Drepper's (glibc maintainer) upstream fixes for nscd corruption and crashing

patch:
-> minimal patch attached

testcase:
1. enable nscd in multi-user and/or NFS environment where multiple passwd and group lookups will occur
2. generate lookups
3. nscd may hit assertion after 2x garbage-collection intervals (~60s), else continue lookups

potential regression:
-> none identifiable

Revision history for this message

Matthias Klose (doko) wrote on 2009-01-19:

#12

uploaded, waiting for approval by SRU. renamed the patch to any/cvs-...
please recheck when the package is built in the archive.

Changed in glibc:
status:	New → Fix Committed

Revision history for this message

Martin Pitt (pitti) wrote on 2009-01-20:

#13

Waiting for verification of bug 305901 before processing this, to avoid stacking too many changes on top of each other.

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Martin Pitt (pitti) wrote on 2009-01-29:

#14

Accepted glibc into intrepid-proposed, please test and give feedback here. Please see https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you in advance!

Revision history for this message

Mickaël Carlier (mickael-carlier) wrote on 2009-02-02:

#15

Hi
no more crash since update!!
Good job!

Revision history for this message

Daniel J Blueman (danielblueman) wrote on 2009-02-02:

#16

I've been testing nscd on x86-64 for a few days on two separate systems, and the fix looks good. I need more exposure on i686 before marking this verified, which will be done in the next few days.

Revision history for this message

Daniel J Blueman (danielblueman) wrote on 2009-02-07:

#17

I've been unable to trigger any crashes or regressions with this updated nscd in the last 8 days in multiple environments, so am happy it is in shape for general release. Tags updates.

Revision history for this message

Launchpad Janitor (janitor) wrote on 2009-02-10:

#18

This bug was fixed in the package glibc - 2.8~20080505-0ubuntu9

---------------
glibc (2.8~20080505-0ubuntu9) intrepid-proposed; urgency=low

  [Daniel J Blueman]
  * Add debian/patches/any/cvs-nscd-crash-fix.diff: address nscd
    daemon crashing in mem.c (LP: #256157).

-- Matthias Klose <email address hidden> Mon, 19 Jan 2009 09:38:23 +0100

Changed in glibc:
status:	Fix Committed → Fix Released

Affects		Status	Importance	Assigned to	Milestone
	glibc (Ubuntu)	Fix Released	Undecided	Unassigned
	Intrepid	Fix Released	Undecided	Unassigned

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nscd crashed with SIGSEGV in start_thread()

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nscd crashed with SIGSEGV in start_thread()

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