Greetings! Paul Slootman <[EMAIL PROTECTED]> writes:
> On Tue 24 Feb 2004, Camm Maguire wrote: > > > Greetings! Just wondering if I should cripple gcl/maxima/acl2/axiom > > on alpha to work around this bug, or if its going to get fixed > > sometime soon..... > > Don't hold your breath... :-( :-) Seriously though, this is a pity, as its a major bug which has only recently been introduced on alpha only. I like alpha. I think it should be one of the strongest Debian options. But there don't appear to be even as many users as m68k :-(. > I don't expect that a kernel change would be responsible for this; > my alpha is still running 2.4.19-rc2 (the latest at the time of last > boot :-) and I guess you see the same problem there. Perhaps some libc > change? Yes, this is a libc6.1 issue only. The signal is being delivered (kernel), but sigaction (libc6.1) can't setup the handler to return to the right place. Take care, > > Paul Slootman > > > ============================================================================= > > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=221969 > > ============================================================================= > > > > * To: [EMAIL PROTECTED], [email protected],[EMAIL PROTECTED] > > * Subject: Apparent signal handling errors recently introduced > > * From: Camm Maguire <[EMAIL PROTECTED]> > > * Date: Fri, 06 Feb 2004 12:15:02 -0500 > > * Message-id: <[EMAIL PROTECTED]> > > * Old-return-path: <[EMAIL PROTECTED]> > > > > Greetings! GCL and its compiled programs (maxima, acl2, axiom) can > > make use of a more efficient garbage collection algorithm by > > mprotecting certain pages read only, trapping segmentation faults, and > > then reprotecting the pages read write as necessary. This has been > > working on alpha for a long time. acl2 in particular was last build > > on 20021210 on lully successfully using this mechanism. I've made > > some minor modifications to the acl2 package, and now the build breaks > > on alpha only, apparently. > > > > Debugging on escher shows that apparently the stack is damaged in such > > a way as the program cannot determine where to return after the signal > > handler, in particular the return is one stack level up from where the > > segmentation signal was caught. Is there any recent kernel change > > that could have caused this? > > > > Here is a gdb session: > > > > Starting program: /home/camm/acl2-2.7/raw_nsaved_acl2 > > /home/camm/gcl-2.6.1/unixport/ <init_nsaved_acl2.lsp > > GCL (GNU Common Lisp) April 1994 131072 pages > > Building symbol table for /home/camm/acl2-2.7/raw_nsaved_acl2 .. > > loading /home/camm/gcl-2.6.1/unixport/../lsp/gcl_export.lsp > > ... > > [GC for 5242 RELOCATABLE-BLOCKS pages..(T=764).GC finished] > > [SGC on] > > Program received signal SIGSEGV, Segmentation fault. > > 0x0000000120667b8c in LI20 (V83=0x120d74570) at gcl_sloop.c:530 > > 530 bds_bind(VV[34],(V83)); > > (gdb) bt 5 > > #0 0x0000000120667b8c in LI20 (V83=0x120d74570) at gcl_sloop.c:530 > > #1 0x0000000120666ad8 in L7 () at gcl_sloop.c:230 > > #2 0x00000001204eb984 in funcall (fun=0x120b51380) at eval.c:173 > > #3 0x00000001205336ac in IapplyVector (fun=0x120b51380, nargs=2, > > base=0x12084ea10) at nfunlink.c:239 > > #4 0x00000001204ef2f8 in fLfuncall (fun=0x120b51380) at eval.c:1140 > > (More stack frames follow...) > > (gdb) up > > #1 0x0000000120666ad8 in L7 () at gcl_sloop.c:230 > > 230 base[3]= (*(LnkLI247))(base[2]); > > (gdb) p base > > $35 = (object *) 0x12084ea10 > > (gdb) p &base > > $36 = (object **) 0x11fffe6f8 > > (gdb) c > > Continuing. > > > > Breakpoint 1, memprotect_handler (sig=11, code=4831830752, scp=0x11fffe360, > > addr=0x0) at sgbc.c:1404 > > 1404 int j=page_multiple; > > (gdb) p *(object **) 0x11fffe6f8 > > $37 = (union lispunion **) 0x12084ea10 > > (gdb) display *(object **) 0x11fffe6f8 > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) n > > 1408 faddr=GET_FAULT_ADDR(sig,code,scp,addr); > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) > > 1409 debug_fault = (long) faddr; > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) > > 1413 if (faddr >= core_end || (unsigned long)faddr < DBEGIN) { > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) > > 1422 p = page(faddr); > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) > > 1423 p = ROUND_DOWN_PAGE_NO(p); > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) > > 1424 if (p >= first_protectable_page > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) > > 1433 mprotect(pagetochar(p),page_multiple * PAGESIZE, > > PROT_READ_WRITE); > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) > > 1434 while (--j >= 0) > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) p j > > $38 = 1 > > (gdb) n > > 1435 sgc_type_map[p+j] = sgc_type_map[p+j] | SGC_TEMP_WRITABLE; > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) > > 1434 while (--j >= 0) > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) > > 1457 } > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) bt > > #0 memprotect_handler (sig=11, code=4831830752, scp=0x11fffe360, addr=0x0) > > at sgbc.c:1457 > > #1 0x000002000022c858 in __open_catalog () from /lib/libc.so.6.1 > > #2 0x0000000120666ad8 in L7 () at gcl_sloop.c:230 > > (gdb) c > > Continuing. > > > > Program received signal SIGSEGV, Segmentation fault. > > 0x0000000120666ae4 in L7 () at gcl_sloop.c:230 > > 230 base[3]= (*(LnkLI247))(base[2]); > > 1: *(union lispunion ***) 4831831800 = (union lispunion **) 0x12084ea10 > > (gdb) bt > > #0 0x0000000120666ae4 in L7 () at gcl_sloop.c:230 > > (gdb) p &base > > $39 = (object **) 0x12080b74c > > (gdb) p base[0] > > Cannot access memory at address 0x20add6c800000000 > > (gdb) > > > -- Camm Maguire [EMAIL PROTECTED] ========================================================================== "The earth is but one country, and mankind its citizens." -- Baha'u'llah
