Date: Wed, 06 Apr 2011 10:17:00 -0700 From: Julian Elischer <julian@freebsd.org> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-current@freebsd.org, Justin Hibbits <chmeeedalf@gmail.com>, Navdeep Parhar <nparhar@gmail.com>, FreeBSD Current <current@freebsd.org> Subject: Re: KGDB stack traces in the kernel. Message-ID: <4D9CA00C.20307@freebsd.org> In-Reply-To: <201104060845.11771.jhb@freebsd.org> References: <4D9A4CE5.5090900@freebsd.org> <4D9B7C92.6030901@freebsd.org> <BANLkTinPdVUac6YGwf4GvOE7gtndbQERaQ@mail.gmail.com> <201104060845.11771.jhb@freebsd.org>
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On 4/6/11 5:45 AM, John Baldwin wrote: > On Tuesday, April 05, 2011 4:35:44 pm Navdeep Parhar wrote: >> On Tue, Apr 5, 2011 at 1:33 PM, Julian Elischer<julian@freebsd.org> wrote: >>> On 4/4/11 6:04 PM, Justin Hibbits wrote: >>> >> What does ddb do? It always seems to get this stuff correct. > ddb knows to stop when it gets to a non-kernel address, and it uses string > compares on function names to identify trap frames. For example in > sys/amd64/amd64/db_trace.c: > > > if (strcmp(name, "calltrap") == 0 || > strcmp(name, "fork_trampoline") == 0 || > strcmp(name, "nmi_calltrap") == 0 || > strcmp(name, "Xdblfault") == 0) > frame_type = TRAP; > > Hah, kgdb just needs to be updated (this is from trgt_amd64.c): > > const struct frame_unwind * > kgdb_trgt_trapframe_sniffer(struct frame_info *next_frame) > { > char *pname; > CORE_ADDR pc; > > pc = frame_pc_unwind(next_frame); > pname = NULL; > find_pc_partial_function(pc,&pname, NULL, NULL); > if (pname == NULL) > return (NULL); > if (strcmp(pname, "calltrap") == 0 || > strcmp(pname, "nmi_calltrap") == 0 || > (pname[0] == 'X'&& pname[1] != '_')) > return (&kgdb_trgt_trapframe_unwind); > /* printf("%s: %lx =%s\n", __func__, pc, pname); */ > return (NULL); > } > I'll give that a try > Can probably just add 'fork_trampoline' to that conditional. I think i386 > needs a similar fix in kgdb. Not sure about other architectures: > > Index: trgt_amd64.c > =================================================================== > --- trgt_amd64.c (revision 220190) > +++ trgt_amd64.c (working copy) > @@ -184,6 +184,7 @@ > if (pname == NULL) > return (NULL); > if (strcmp(pname, "calltrap") == 0 || > + strcmp(pname, "fork_trampoline") == 0 || > strcmp(pname, "nmi_calltrap") == 0 || > (pname[0] == 'X'&& pname[1] != '_')) > return (&kgdb_trgt_trapframe_unwind); > Index: trgt_i386.c > =================================================================== > --- trgt_i386.c (revision 220190) > +++ trgt_i386.c (working copy) > @@ -374,6 +374,7 @@ > if (strcmp(pname, "dblfault_handler") == 0) > return (&kgdb_trgt_dblfault_unwind); > if (strcmp(pname, "calltrap") == 0 || > + strcmp(pname, "fork_trampoline") == 0 || > (pname[0] == 'X'&& pname[1] != '_')) > return (&kgdb_trgt_trapframe_unwind); > /* printf("%s: %llx =%s\n", __func__, pc, pname); */ >
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