On Wed, 12 Mar 2003, Tim Robbins wrote: > Compile, run under gdb, then type "print test()" when the program receives > SIGABRT. Seems to work incorrectly on 4.7 too. > > #include <stdio.h> > #include <stdlib.h> > > void > test(void) > { > > puts("hello"); > } > > int > main(int argc, char *argv[]) > { > > abort(); > exit(0); > }
Thanks. At last it is possible to reproduce this bug :-). The bug seems to be that issignal() is quite broken. It gets called for masked signals in the P_TRACED case, but never does anything for masked signals, but at least the following things poing to a need for doing something for masked signals: - the special case for P_TRACED in SIGPENDING() - the incorrect behaviour of the above program in RELENG_4. I think it misbehaves in the same way under -current except in the INVARIANTS case the sanity check spews kernel printfs. - code in NetBSD's issignal() to do something in the (p->p_stat == SSTOP) case without even checking if there are any signals (masked or not). This bug seems to go back to at least FreeBSD-1 (Net/2). SIGPENDING() is also inconsistent with issignal() in the P_PPWAIT case. I think this just wastes time doing null calls to issignal(), and triggers the INVARIANTS check in the same way as the P_TRACED case (see below). This seems to go back to FreeBSD-1 too. SIGPENDING() is consistent with issignal() in the S_SIG case, but this may be wrong since S_SIG is similar to P_TRACED. The invariants check gets trigger as follows: - sigpending() is called correctly. - ast() clears the flags set by sigpending() and "handles" the signal using "while ((sig == cursig(td)) != 0) postsig()". But cursig() doesn't find any signals since all the pending ones are masked. - userret() checks that pending signals were handled. It finds unhandled masked ones and thinks they needed handling because P_TRACED is set. (IIRC, there is only a SIGTRAP pending to begin with, but attempting to control the process using ^C^Z gave masked SIGINTs and SIGSTOPs too). Appart from the diagnostic, the incorrect working in -current is to loop endlessly calling ast() and usrret(). ^C^Z doesn't stop it because they are masked. Bruce To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-current" in the body of the message