On Sun, Jun 17, 2012 at 09:58:46PM +0000, Thorsten Glaser wrote: >Steve McIntyre dixit: > >>Digging further with the built-in debug TRACE function, I can see >>problems in usr/dash/eval.c:evalcommand(). The place where cmd >>switches from non-NULL to NULL is >> >> status = redirectsafe(cmd->ncmd.redirect, REDIR_PUSH|REDIR_SAVEFD2); > >Yeah, I got approximately so far too, with gdb (despite my >extremely limited gdb-fu). > >>Interestingly, adding more TRACE() calls makes the problem go >>away. \o/ Classic Heisenbug behaviour. > >Right. Interestingly itâs always the shells you notice this in. >Last time I saw this, it was a problem having to do with argument >passing (registers vs. stack, how many, which, and where), including >return value placement. But Iâm out of guesses.
More debugging results: * If I replace -Os with -O0 to disable optimisation, the crash goes away too. Suggests (maybe) a compiler bug here... * There's a real bug in the ARM assembly version of longjmp in usr/klibc/arch/arm/setjmp.S: it will always pass back its first argument as a return value, even if it's 0 (see the man page for more details). Oddly, the Thumb implementation in the same file *is* correct! -- Steve McIntyre, Cambridge, UK. st...@einval.com We don't need no education. We don't need no thought control. -- To UNSUBSCRIBE, email to debian-bugs-rc-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
