@@ -574,6 +574,45 @@ reduction of features at Xen's disposal to manage guests.
### cpuinfo (x86)
> `= <boolean>`
+### crash-debug-debugkey
+### crash-debug-hwdom
+### crash-debug-kexeccmd
+### crash-debug-panic
+### crash-debug-watchdog
+> `= <string>`
+
+> Can be modified at runtime
+
+Specify debug-key actions in cases of crashes. Each of the parameters applies
+to a different crash reason. The `<string>` is a sequence of debug key
+characters, with `+` having the special meaning of a 10 millisecond pause.
+
+`crash-debug-debugkey` will be used for crashes induced by the `C` debug
+key (i.e. manually induced crash).
+
+`crash-debug-hwdom` denotes a crash of dom0.
+
+`crash-debug-kexeccmd` is an explicit request of dom0 to continue with the
+kdump kernel via kexec.
+
+`crash-debug-panic` is a crash of the hypervisor.
+
+`crash-debug-watchdog` is a crash due to the watchdog timer expiring.
+
+It should be noted that dumping diagnosis data to the console can fail in
+multiple ways (missing data, hanging system, ...) depending on the reason
+of the crash, which might have left the hypervisor in a bad state.
+
+So e.g. `crash-debug-watchdog=0+0r` would dump dom0 state twice with 10
+milliseconds between the two state dumps, followed by the run queues of the
+hypervisor, if the system crashes due to a watchdog timeout.
+
+These parameters should be used carefully, as e.g. specifying
+`crash-debug-debugkey=C` would result in an endless loop. Depending on the
+reason of the system crash it might happen that triggering some debug key
+action will result in a hang instead of dumping data and then doing a
+reboot or crash dump.
+
### crashinfo_maxaddr
> `= <size>`
@@ -373,10 +373,12 @@ static int kexec_common_shutdown(void)
return 0;
}
-void kexec_crash(void)
+void kexec_crash(enum crash_reason reason)
{
int pos;
+ keyhandler_crash_action(reason);
+
pos = (test_bit(KEXEC_FLAG_CRASH_POS, &kexec_flags) != 0);
if ( !test_bit(KEXEC_IMAGE_CRASH_BASE + pos, &kexec_flags) )
return;
@@ -409,7 +411,7 @@ static long kexec_reboot(void *_image)
static void do_crashdump_trigger(unsigned char key)
{
printk("'%c' pressed -> triggering crashdump\n", key);
- kexec_crash();
+ kexec_crash(CRASHREASON_DEBUGKEY);
printk(" * no crash kernel loaded!\n");
}
@@ -840,7 +842,7 @@ static int kexec_exec(XEN_GUEST_HANDLE_PARAM(void) uarg)
ret = continue_hypercall_on_cpu(0, kexec_reboot, image);
break;
case KEXEC_TYPE_CRASH:
- kexec_crash(); /* Does not return */
+ kexec_crash(CRASHREASON_KEXECCMD); /* Does not return */
break;
}
@@ -3,7 +3,9 @@
*/
#include <asm/regs.h>
+#include <xen/delay.h>
#include <xen/keyhandler.h>
+#include <xen/param.h>
#include <xen/shutdown.h>
#include <xen/event.h>
#include <xen/console.h>
@@ -507,6 +509,42 @@ void __init initialize_keytable(void)
}
}
+#define CRASHACTION_SIZE 32
+static char crash_debug_panic[CRASHACTION_SIZE];
+static char crash_debug_hwdom[CRASHACTION_SIZE];
+static char crash_debug_watchdog[CRASHACTION_SIZE];
+static char crash_debug_kexeccmd[CRASHACTION_SIZE];
+static char crash_debug_debugkey[CRASHACTION_SIZE];
+
+static char *crash_action[CRASHREASON_N] = {
+ [CRASHREASON_PANIC] = crash_debug_panic,
+ [CRASHREASON_HWDOM] = crash_debug_hwdom,
+ [CRASHREASON_WATCHDOG] = crash_debug_watchdog,
+ [CRASHREASON_KEXECCMD] = crash_debug_kexeccmd,
+ [CRASHREASON_DEBUGKEY] = crash_debug_debugkey,
+};
+
+string_runtime_param("crash-debug-panic", crash_debug_panic);
+string_runtime_param("crash-debug-hwdom", crash_debug_hwdom);
+string_runtime_param("crash-debug-watchdog", crash_debug_watchdog);
+string_runtime_param("crash-debug-kexeccmd", crash_debug_kexeccmd);
+string_runtime_param("crash-debug-debugkey", crash_debug_debugkey);
+
+void keyhandler_crash_action(enum crash_reason reason)
+{
+ const char *action = crash_action[reason];
+ struct cpu_user_regs *regs = get_irq_regs() ? : guest_cpu_user_regs();
+
+ while ( *action )
+ {
+ if ( *action == '+' )
+ mdelay(10);
+ else
+ handle_keypress(*action, regs);
+ action++;
+ }
+}
+
/*
* Local variables:
* mode: C
@@ -43,7 +43,7 @@ void hwdom_shutdown(u8 reason)
case SHUTDOWN_crash:
debugger_trap_immediate();
printk("Hardware Dom%u crashed: ", hardware_domain->domain_id);
- kexec_crash();
+ kexec_crash(CRASHREASON_HWDOM);
maybe_reboot();
break; /* not reached */
@@ -56,7 +56,7 @@ void hwdom_shutdown(u8 reason)
case SHUTDOWN_watchdog:
printk("Hardware Dom%u shutdown: watchdog rebooting machine\n",
hardware_domain->domain_id);
- kexec_crash();
+ kexec_crash(CRASHREASON_WATCHDOG);
machine_restart(0);
break; /* not reached */
@@ -1271,7 +1271,7 @@ void panic(const char *fmt, ...)
debugger_trap_immediate();
- kexec_crash();
+ kexec_crash(CRASHREASON_PANIC);
if ( opt_noreboot )
machine_halt();
@@ -1,6 +1,8 @@
#ifndef __XEN_KEXEC_H__
#define __XEN_KEXEC_H__
+#include <xen/keyhandler.h>
+
#ifdef CONFIG_KEXEC
#include <public/kexec.h>
@@ -48,7 +50,7 @@ void machine_kexec_unload(struct kexec_image *image);
void machine_kexec_reserved(xen_kexec_reserve_t *reservation);
void machine_reboot_kexec(struct kexec_image *image);
void machine_kexec(struct kexec_image *image);
-void kexec_crash(void);
+void kexec_crash(enum crash_reason reason);
void kexec_crash_save_cpu(void);
struct crash_xen_info *kexec_crash_save_info(void);
void machine_crash_shutdown(void);
@@ -82,7 +84,11 @@ void vmcoreinfo_append_str(const char *fmt, ...)
#define kexecing 0
static inline void kexec_early_calculations(void) {}
-static inline void kexec_crash(void) {}
+static inline void kexec_crash(enum crash_reason reason)
+{
+ keyhandler_crash_action(reason);
+}
+
static inline void kexec_crash_save_cpu(void) {}
static inline void set_kexec_crash_area_size(u64 system_ram) {}
@@ -48,4 +48,15 @@ void register_irq_keyhandler(unsigned char key,
/* Inject a keypress into the key-handling subsystem. */
extern void handle_keypress(unsigned char key, struct cpu_user_regs *regs);
+enum crash_reason {
+ CRASHREASON_PANIC,
+ CRASHREASON_HWDOM,
+ CRASHREASON_WATCHDOG,
+ CRASHREASON_KEXECCMD,
+ CRASHREASON_DEBUGKEY,
+ CRASHREASON_N
+};
+
+void keyhandler_crash_action(enum crash_reason reason);
+
#endif /* __XEN_KEYHANDLER_H__ */
When the host crashes it would sometimes be nice to have additional debug data available which could be produced via debug keys, but halting the server for manual intervention might be impossible due to the need to reboot/kexec rather sooner than later. Add support for automatic debug key actions in case of crashes which can be activated via boot- or runtime-parameter. Depending on the type of crash the desired data might be different, so support different settings for the possible types of crashes. The parameter is "crash-debug" with the following syntax: crash-debug-<type>=<string> with <type> being one of: panic, hwdom, watchdog, kexeccmd, debugkey and <string> a sequence of debug key characters with '+' having the special semantics of a 10 millisecond pause. So "crash-debug-watchdog=0+0qr" would result in special output in case of watchdog triggered crash (dom0 state, 10 ms pause, dom0 state, domain info, run queues). Signed-off-by: Juergen Gross <jgross@suse.com> --- V2: - switched special character '.' to '+' (Jan Beulich) - 10 ms instead of 1 s pause (Jan Beulich) - added more text to the boot parameter description (Jan Beulich) --- docs/misc/xen-command-line.pandoc | 39 +++++++++++++++++++++++++++++++ xen/common/kexec.c | 8 ++++--- xen/common/keyhandler.c | 38 ++++++++++++++++++++++++++++++ xen/common/shutdown.c | 4 ++-- xen/drivers/char/console.c | 2 +- xen/include/xen/kexec.h | 10 ++++++-- xen/include/xen/keyhandler.h | 11 +++++++++ 7 files changed, 104 insertions(+), 8 deletions(-)