gnu/108229: Infinite loop with kgdb while debugging mis-match kernel/core

[Jessica Han]

>Number:         108229
>Category:       gnu
>Synopsis:       Infinite loop with kgdb while debugging mis-match kernel/core
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Tue Jan 23 01:00:36 GMT 2007
>Closed-Date:
>Last-Modified:
>Originator:     Jessica Han
>Release:        FreeBSD 6.1-RELEASE
>Organization:
Juniper Networks
>Environment:
i386
>Description:
I got an infinite loop while trying to debug a kernel core on FreeBSD 6.1, note that I happened to be debugging a wrong "kernel" binary for the core dump. 
# uname -sr
 FreeBSD 6.1-RELEASE
#kgdb kernel vmcore.0
kgdb: kvm_read: invalid address (0x50012)
kgdb: kvm_read: invalid address (0x7)
kgdb: kvm_read: invalid address (0xf5c)
kgdb: kvm_read: invalid address (0xf5c)
kgdb: kvm_read: invalid address (0xf5c)


 
 I've got a patch to fix it, can somebody review and commit it if it is okay? Thanks,

Jessica

>How-To-Repeat:

>Fix:


Patch attached with submission follows:

--- /6.1-vanila/src/gnu/usr.bin/gdb/kgdb/kthr.c	Wed Sep 14 22:32:10 2005
+++ gnu/usr.bin/gdb/kgdb/kthr.c	Thu Nov 16 12:37:41 2006
@@ -92,12 +92,16 @@
 		dumptid = -1;
 
 	while (paddr != 0) {
-		if (kvm_read(kvm, paddr, &p, sizeof(p)) != sizeof(p))
+		if (kvm_read(kvm, paddr, &p, sizeof(p)) != sizeof(p)) {
 			warnx("kvm_read: %s", kvm_geterr(kvm));
+			break;
+		}
 		addr = (uintptr_t)TAILQ_FIRST(&p.p_threads);
 		while (addr != 0) {
-			if (kvm_read(kvm, addr, &td, sizeof(td)) != sizeof(td))
+			if (kvm_read(kvm, addr, &td, sizeof(td)) != sizeof(td)) {
 				warnx("kvm_read: %s", kvm_geterr(kvm));
+				break;
+			}
 			kt = malloc(sizeof(*kt));
 			kt->next = first;
 			kt->kaddr = addr;

>Release-Note:
>Audit-Trail:
>Unformatted: