svn commit: r344905 - in stable: 11/sys/amd64/amd64 11/sys/arm/arm 11/sys/arm64/arm64 11/sys/i386/i386 11/sys/kern 11/sys/mips/mips 11/sys/powerpc/powerpc 11/sys/sys 12/sys/amd64/amd64 12/sys/arm/a...
John Baldwin
jhb at FreeBSD.org
Fri Mar 8 00:20:39 UTC 2019
Author: jhb
Date: Fri Mar 8 00:20:37 2019
New Revision: 344905
URL: https://svnweb.freebsd.org/changeset/base/344905
Log:
MFC 340020: Don't enter DDB for fatal traps before panic by default.
Add a new 'debugger_on_trap' knob separate from 'debugger_on_panic'
and make the calls to kdb_trap() in MD fatal trap handlers prior to
calling panic() conditional on this new knob instead of
'debugger_on_panic'. Disable the new knob by default. Developers who
wish to recover from a fatal fault by adjusting saved register state
and retrying the faulting instruction can still do so by enabling the
new knob. However, for the more common case this makes the user
experience for panics due to a fatal fault match the user experience
for other panics, e.g. 'c' in DDB will generate a crash dump and
reboot the system rather than being stuck in an infinite loop of fatal
fault messages and DDB prompts.
Modified:
stable/12/sys/amd64/amd64/trap.c
stable/12/sys/arm/arm/trap-v4.c
stable/12/sys/arm/arm/trap-v6.c
stable/12/sys/arm64/arm64/trap.c
stable/12/sys/i386/i386/trap.c
stable/12/sys/kern/kern_shutdown.c
stable/12/sys/mips/mips/trap.c
stable/12/sys/powerpc/powerpc/trap.c
stable/12/sys/sys/kdb.h
Directory Properties:
stable/12/ (props changed)
Changes in other areas also in this revision:
Modified:
stable/11/sys/amd64/amd64/trap.c
stable/11/sys/arm/arm/trap-v4.c
stable/11/sys/arm/arm/trap-v6.c
stable/11/sys/arm64/arm64/trap.c
stable/11/sys/i386/i386/trap.c
stable/11/sys/kern/kern_shutdown.c
stable/11/sys/mips/mips/trap.c
stable/11/sys/powerpc/powerpc/trap.c
stable/11/sys/sys/kdb.h
Directory Properties:
stable/11/ (props changed)
Modified: stable/12/sys/amd64/amd64/trap.c
==============================================================================
--- stable/12/sys/amd64/amd64/trap.c Thu Mar 7 23:03:39 2019 (r344904)
+++ stable/12/sys/amd64/amd64/trap.c Fri Mar 8 00:20:37 2019 (r344905)
@@ -933,7 +933,7 @@ trap_fatal(frame, eva)
curproc->p_pid, curthread->td_name);
#ifdef KDB
- if (debugger_on_panic) {
+ if (debugger_on_trap) {
kdb_why = KDB_WHY_TRAP;
handled = kdb_trap(type, 0, frame);
kdb_why = KDB_WHY_UNSET;
Modified: stable/12/sys/arm/arm/trap-v4.c
==============================================================================
--- stable/12/sys/arm/arm/trap-v4.c Thu Mar 7 23:03:39 2019 (r344904)
+++ stable/12/sys/arm/arm/trap-v4.c Fri Mar 8 00:20:37 2019 (r344905)
@@ -456,7 +456,7 @@ dab_fatal(struct trapframe *tf, u_int fsr, u_int far,
printf(", pc =%08x\n\n", tf->tf_pc);
#ifdef KDB
- if (debugger_on_panic) {
+ if (debugger_on_trap) {
kdb_why = KDB_WHY_TRAP;
handled = kdb_trap(fsr, 0, tf);
kdb_why = KDB_WHY_UNSET;
Modified: stable/12/sys/arm/arm/trap-v6.c
==============================================================================
--- stable/12/sys/arm/arm/trap-v6.c Thu Mar 7 23:03:39 2019 (r344904)
+++ stable/12/sys/arm/arm/trap-v6.c Fri Mar 8 00:20:37 2019 (r344905)
@@ -599,7 +599,7 @@ abort_fatal(struct trapframe *tf, u_int idx, u_int fsr
printf(", pc =%08x\n\n", tf->tf_pc);
#ifdef KDB
- if (debugger_on_panic) {
+ if (debugger_on_trap) {
kdb_why = KDB_WHY_TRAP;
kdb_trap(fsr, 0, tf);
kdb_why = KDB_WHY_UNSET;
Modified: stable/12/sys/arm64/arm64/trap.c
==============================================================================
--- stable/12/sys/arm64/arm64/trap.c Thu Mar 7 23:03:39 2019 (r344904)
+++ stable/12/sys/arm64/arm64/trap.c Fri Mar 8 00:20:37 2019 (r344905)
@@ -256,7 +256,7 @@ no_pmap_fault:
printf(" esr: %.8lx\n", esr);
#ifdef KDB
- if (debugger_on_panic) {
+ if (debugger_on_trap) {
kdb_why = KDB_WHY_TRAP;
handled = kdb_trap(ESR_ELx_EXCEPTION(esr), 0,
frame);
Modified: stable/12/sys/i386/i386/trap.c
==============================================================================
--- stable/12/sys/i386/i386/trap.c Thu Mar 7 23:03:39 2019 (r344904)
+++ stable/12/sys/i386/i386/trap.c Fri Mar 8 00:20:37 2019 (r344905)
@@ -977,7 +977,7 @@ trap_fatal(frame, eva)
curproc->p_pid, curthread->td_name);
#ifdef KDB
- if (debugger_on_panic) {
+ if (debugger_on_trap) {
kdb_why = KDB_WHY_TRAP;
frame->tf_err = eva; /* smuggle fault address to ddb */
handled = kdb_trap(type, 0, frame);
Modified: stable/12/sys/kern/kern_shutdown.c
==============================================================================
--- stable/12/sys/kern/kern_shutdown.c Thu Mar 7 23:03:39 2019 (r344904)
+++ stable/12/sys/kern/kern_shutdown.c Fri Mar 8 00:20:37 2019 (r344905)
@@ -115,13 +115,18 @@ SYSCTL_INT(_kern, OID_AUTO, panic_reboot_wait_time, CT
#ifdef KDB
#ifdef KDB_UNATTENDED
-int debugger_on_panic = 0;
+static int debugger_on_panic = 0;
#else
-int debugger_on_panic = 1;
+static int debugger_on_panic = 1;
#endif
SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic,
CTLFLAG_RWTUN | CTLFLAG_SECURE,
&debugger_on_panic, 0, "Run debugger on kernel panic");
+
+int debugger_on_trap = 0;
+SYSCTL_INT(_debug, OID_AUTO, debugger_on_trap,
+ CTLFLAG_RWTUN | CTLFLAG_SECURE,
+ &debugger_on_trap, 0, "Run debugger on kernel trap before panic");
#ifdef KDB_TRACE
static int trace_on_panic = 1;
Modified: stable/12/sys/mips/mips/trap.c
==============================================================================
--- stable/12/sys/mips/mips/trap.c Thu Mar 7 23:03:39 2019 (r344904)
+++ stable/12/sys/mips/mips/trap.c Fri Mar 8 00:20:37 2019 (r344905)
@@ -1100,7 +1100,7 @@ err:
#endif
#ifdef KDB
- if (debugger_on_panic) {
+ if (debugger_on_trap) {
kdb_why = KDB_WHY_TRAP;
kdb_trap(type, 0, trapframe);
kdb_why = KDB_WHY_UNSET;
Modified: stable/12/sys/powerpc/powerpc/trap.c
==============================================================================
--- stable/12/sys/powerpc/powerpc/trap.c Thu Mar 7 23:03:39 2019 (r344904)
+++ stable/12/sys/powerpc/powerpc/trap.c Fri Mar 8 00:20:37 2019 (r344905)
@@ -455,7 +455,7 @@ trap_fatal(struct trapframe *frame)
printtrap(frame->exc, frame, 1, (frame->srr1 & PSL_PR));
#ifdef KDB
- if (debugger_on_panic) {
+ if (debugger_on_trap) {
kdb_why = KDB_WHY_TRAP;
handled = kdb_trap(frame->exc, 0, frame);
kdb_why = KDB_WHY_UNSET;
Modified: stable/12/sys/sys/kdb.h
==============================================================================
--- stable/12/sys/sys/kdb.h Thu Mar 7 23:03:39 2019 (r344904)
+++ stable/12/sys/sys/kdb.h Fri Mar 8 00:20:37 2019 (r344905)
@@ -62,7 +62,7 @@ struct kdb_dbbe {
DATA_SET(kdb_dbbe_set, name##_dbbe)
extern u_char kdb_active; /* Non-zero while in debugger. */
-extern int debugger_on_panic; /* enter the debugger on panic. */
+extern int debugger_on_trap; /* enter the debugger on trap. */
extern struct kdb_dbbe *kdb_dbbe; /* Default debugger backend or NULL. */
extern struct trapframe *kdb_frame; /* Frame to kdb_trap(). */
extern struct pcb *kdb_thrctx; /* Current context. */
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