Red Hat Bugzilla – Bug 150647
glibc detected free(): invalid next size (fast): 0x08bfc970
Last modified: 2007-11-30 17:07:16 EST
See the bug #150582 for more info. It seems that this bug affect FC3 and RHEL4 and is related to glibc (try Google).
This is not a bug in glibc, but in the application that triggered it. glibc just reports that the application has broken memory allocation handling and terminates the process, as that can be a sign of exploit. If you run the program with MALLOC_CHECK_=0, these checks will be gone (unless the program is suid/sgid). The program should be run under valgrind or LD_PRELOAD=libefence.so.0 to find out where exactly its memory allocation handling is broken.
Is this a new feature in glibc in compare to RHEL3's glibc?
Yes, see RELEASE-NOTES: glibc o The version of glibc provided with Red Hat Enterprise Linux 4 performs additional internal sanity checks to prevent and detect data corruption as early as possible. By default, should corruption be detected, a message similar to the following will be displayed on standard error (or logged via syslog if stderr is not open): *** glibc detected *** double free or corruption: 0x0937d008 *** By default, the program that generated this error will also be killed; however, this (and whether or not an error message is generated) can be controlled via the MALLOC_CHECK_ environment variable. The following settings are supported: o 0 -- Do not generate an error message, and do not kill the program o 1 -- Generate an error message, but do not kill the program o 2 -- Do not generate an error message, but kill the program o 3 -- Generate an error message and kill the program Note If MALLOC_CHECK_ is explicitly set a value other than 0, this causes glibc to perform more tests that are more extensive than the default, and may impact performance. Should you have a program from a third party ISV that triggers these corruption checks and displays a message, you should file a defect report with the application's vendor, since this indicates a serious bug.
Thank you for your exact and fast help. I did not make a connection between those two informations. So it seems that Samba from RHEL4 has a serious bug...