Hi, What you reported seems unrelated to the original issue. It's better to open a new bug if you believe there is in issue in glibc.
On 2023-08-09 10:46, Paul Szabo wrote: > Maybe related: seems that the default for "mcheck" or MALLOC_CHECK_ has > changed. > > I observe an oddity. I only noticed this recently, with libc6 version > 2.36-9+deb12u1; reverting to previous 2.36-9 did not seem to help. > > The issue. Sending SIGHUP to the inetd(8) process should cause it to > re-load its configuration, but instead it elicits > > free(): double free detected in tcache 2 > > and an abort. This is easiest seen (after "systemctl stop inetd") with > > root# inetd -d -i & sleep 1; kill -HUP $!; sleep 1; jobs > [1] 2431 > ADD: ident proto=tcp4, wait.max=1.256 user:group=identd:(default) builtin=0 > server=/usr/sbin/identd > free(): double free detected in tcache 2 > [1]+ Aborted inetd -d -i > root# This is very likely a bug in inetd. There is no default value in MALLOC_CHECK_, by default a fast memory allocator which is not tolerant against simple errors is used, and thus just aborts in that case. > Sanity(?) is restored by using MALLOC_CHECK_=0 (needs LD_PRELOAD): > > root# LD_PRELOAD=libc_malloc_debug.so MALLOC_CHECK_=0 inetd -d -i & sleep > 1; kill -HUP $!; sleep 1; jobs; kill $!; sleep 1; jobs > [1] 2437 > ADD: ident proto=tcp4, wait.max=1.256 user:group=identd:(default) builtin=0 > server=/usr/sbin/identd > REDO: ident proto=tcp4, wait.max=1.256 user:group=identd:(default) > builtin=0 server=/usr/sbin/identd > [1]+ Running LD_PRELOAD=libc_malloc_debug.so > MALLOC_CHECK_=0 inetd -d -i & > [1]+ Done LD_PRELOAD=libc_malloc_debug.so > MALLOC_CHECK_=0 inetd -d -i > root# > > To compound the oddity, the value of MALLOC_CHECK_ or even its presence > seems ignored, just the LD_PRELOAD=libc_malloc_debug.so "fixes" the > issue. Since glibc 2.34, the debugging features in malloc such as the MALLOC_CHECK_ environment variable are not built-in anymore and require to preload the libc_malloc_debug.so library. This allows one to change the level of checks through the MALLOC_CHECK_ environment variable. Regards Aurelien -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurel...@aurel32.net http://aurel32.net
