https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=213778
--- Comment #1 from Mark Millard <mar...@dsl-only.net> --- (In reply to Mark Millard from comment #0) The following is from a report about a different issue than truss but what it also says about the value reported bh gdb for t->cs.number when truss gets the segmentation fault may be relevant information for truss's behavior. . . Using "ktrace -i -t +fw" it looks like every repeat of the problem ends up with the following sort of sequence (a variation is shown later): 34629 cc1 CALL mmap(0,0x4000,0x3<PROT_READ|PROT_WRITE>,0x1002<MAP_PRIVATE|MAP_ANON>,0xffffffff,0x1c,0,0) 34629 cc1 RET mmap 568225792/0x21de7000 34629 cc1 PFLT 0x21de7000 VM_PROT_WRITE 34629 cc1 PRET KERN_SUCCESS 34629 cc1 PFLT 0x21de8000 VM_PROT_WRITE 34629 cc1 PRET KERN_SUCCESS 34629 cc1 PFLT 0x21de9000 VM_PROT_WRITE 34629 cc1 PRET KERN_SUCCESS 34629 cc1 PFLT 0x21dea000 VM_PROT_WRITE 34629 cc1 PRET KERN_SUCCESS 34629 cc1 PFLT 0x229e8000 VM_PROT_WRITE 34629 cc1 PRET KERN_SUCCESS 34629 cc1 PFLT 0x229e9000 VM_PROT_WRITE 34629 cc1 PRET KERN_SUCCESS 34629 cc1 PFLT 0x229ea000 VM_PROT_WRITE 34629 cc1 PRET KERN_SUCCESS 34629 cc1 CSW stop user "ast" 34629 cc1 CSW resume user "ast" 34629 cc1 PFLT 0x229eb000 VM_PROT_WRITE 34629 cc1 PRET KERN_SUCCESS 34629 cc1 PFLT 0x229ec000 VM_PROT_WRITE 34629 cc1 PRET KERN_SUCCESS 34629 cc1 CALL [-17504] 34629 cc1 RET [-17504] -1 errno 78 Function not implemented 34629 cc1 PSIG SIGSYS SIG_DFL code=SI_KERNEL 34629 cc1 NAMI "cc1.core" 34630 as CSW stop kernel "piperd" 34630 as Events dropped. 34630 as RET read 0 34630 as CALL close(0) 34630 as RET close 0 . . . I'll note that for the source this was compiling I used gdb truss with run -feH -o truss.log and it reported: (gdb) print t->cs.number $5 = 580828064 FYI: 580828064 = 0x229EBBA0 where the truss segmentation fault was at line 385 of the following (sc==NULL in the context): 380 t->cs.name = sysdecode_syscallname(t->proc->abi->abi, t->cs.number); 381 if (t->cs.name == NULL) (gdb) 382 fprintf(info->outfile, "-- UNKNOWN %s SYSCALL %d --\n", 383 t->proc->abi->type, t->cs.number); 384 385 sc = get_syscall(t->cs.name, narg); 386 t->cs.nargs = sc->nargs; 387 assert(sc->nargs <= nitems(t->cs.s_args)); 388 389 t->cs.sc = sc; The 229E matched the upper part of local PFLT activity around the user "ast" CSW's, including just before the bad call. But the details do vary some based on the source file being compiled. For example here the user "ast" CSW's are just before the mmap but are still just after the 0x229ea000 PFLT: 34698 cc1 PRET KERN_SUCCESS 34698 cc1 PFLT 0xbfbf2000 VM_PROT_WRITE 34698 cc1 PRET KERN_SUCCESS 34698 cc1 PFLT 0x229e7000 VM_PROT_WRITE 34698 cc1 PRET KERN_SUCCESS 34698 cc1 PFLT 0x229e8000 VM_PROT_WRITE 34698 cc1 PRET KERN_SUCCESS 34698 cc1 PFLT 0x229e9000 VM_PROT_WRITE 34698 cc1 PRET KERN_SUCCESS 34698 cc1 PFLT 0x229ea000 VM_PROT_WRITE 34698 cc1 PRET KERN_SUCCESS 34698 cc1 CSW stop user "ast" 34698 cc1 CSW resume user "ast" 34698 cc1 CALL mmap(0,0x4000,0x3<PROT_READ|PROT_WRITE>,0x1002<MAP_PRIVATE|MAP_ANON>,0xffffffff,0,0,0) 34698 cc1 RET mmap 568225792/0x21de7000 34698 cc1 PFLT 0x21de7000 VM_PROT_WRITE 34698 cc1 PRET KERN_SUCCESS 34698 cc1 PFLT 0x21de8000 VM_PROT_WRITE 34698 cc1 PRET KERN_SUCCESS 34698 cc1 PFLT 0x21de9000 VM_PROT_WRITE 34698 cc1 PRET KERN_SUCCESS 34698 cc1 PFLT 0x21dea000 VM_PROT_WRITE 34698 cc1 PRET KERN_SUCCESS 34698 cc1 PFLT 0x229eb000 VM_PROT_WRITE 34698 cc1 PRET KERN_SUCCESS 34698 cc1 CALL [-25840] 34698 cc1 RET [-25840] -1 errno 78 Function not implemented 34698 cc1 PSIG SIGSYS SIG_DFL code=SI_KERNEL 34698 cc1 NAMI "cc1.core" 34699 as CSW stop kernel "piperd" 34699 as Events dropped. 34699 as RET read 0 34699 as CALL close(0) 34699 as RET close 0 -25840 in 2's complement is: 0xF...F9B10 Here doing the gdb truss instead reports: (gdb) print t->cs.number $1 = 580819728 and 580819728 = 0x229E9B10 and the 229E part matches several PFLT's in the area, including just before the bad call as well as just before the user "ast"s. Between them are some PFLT's that do not match. I would guess that the 229E in t->cs.number in truss is from the PFLT just before the failing syscall in each case. -- You are receiving this mail because: You are the assignee for the bug. _______________________________________________ freebsd-bugs@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "freebsd-bugs-unsubscr...@freebsd.org"
