[PATCH] 2.5.44: lkcd (6/9): dump trace/dump calls/dump_in_progress

Matt D. Robinson (yakker@aparity.com)
Mon, 21 Oct 2002 03:15:59 -0700

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General modifications in the kernel to allow for dumping to
take place without causing system hangs or other anomalies
(like jobs being scheduled while a dump is taking place).
Also included are additional fields for matching /dev/mem
entries to a System.map file. Most of the changes are for
dealing with exported symbols.

diff -Naur linux-2.5.44.orig/arch/i386/kernel/Makefile linux-2.5.44.lkcd/arch/i386/kernel/Makefile
--- linux-2.5.44.orig/arch/i386/kernel/Makefile Fri Oct 18 21:01:16 2002
+++ linux-2.5.44.lkcd/arch/i386/kernel/Makefile Sat Oct 19 12:39:15 2002
@@ -4,7 +4,7 @@

EXTRA_TARGETS := head.o init_task.o

-export-objs := mca.o i386_ksyms.o time.o
+export-objs := irq.o traps.o mca.o i386_ksyms.o time.o smp.o

obj-y := process.o semaphore.o signal.o entry.o traps.o irq.o vm86.o \
ptrace.o i8259.o ioport.o ldt.o setup.o time.o sys_i386.o \
diff -Naur linux-2.5.44.orig/arch/i386/kernel/irq.c linux-2.5.44.lkcd/arch/i386/kernel/irq.c
--- linux-2.5.44.orig/arch/i386/kernel/irq.c Fri Oct 18 21:01:09 2002
+++ linux-2.5.44.lkcd/arch/i386/kernel/irq.c Sat Oct 19 12:39:15 2002
@@ -32,6 +32,7 @@
#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
+#include <linux/module.h>

#include <asm/atomic.h>
#include <asm/io.h>
@@ -957,3 +958,7 @@
register_irq_proc(i);
}

+EXPORT_SYMBOL(irq_desc);
+#if CONFIG_SMP
+EXPORT_SYMBOL(irq_affinity);
+#endif
diff -Naur linux-2.5.44.orig/arch/i386/kernel/nmi.c linux-2.5.44.lkcd/arch/i386/kernel/nmi.c
--- linux-2.5.44.orig/arch/i386/kernel/nmi.c Fri Oct 18 21:01:56 2002
+++ linux-2.5.44.lkcd/arch/i386/kernel/nmi.c Sat Oct 19 12:39:15 2002
@@ -20,6 +20,7 @@
#include <linux/interrupt.h>
#include <linux/mc146818rtc.h>
#include <linux/kernel_stat.h>
+#include <linux/dump.h>

#include <asm/smp.h>
#include <asm/mtrr.h>
@@ -360,6 +361,13 @@
*/
int sum, cpu = smp_processor_id();

+ /*
+ * Ignore watchdog when dumping is in progress.
+ * Todo: consider using the touch_nmi_watchdog() approach instead
+ */
+ if (dump_in_progress && cpu != dumping_cpu)
+ return;
+
sum = irq_stat[cpu].apic_timer_irqs;

if (last_irq_sums[cpu] == sum) {
@@ -378,6 +386,7 @@
printk("NMI Watchdog detected LOCKUP on CPU%d, eip %08lx, registers:\n", cpu, regs->eip);
show_registers(regs);
printk("console shuts up ...\n");
+ dump("NMI Watchdog Detected", regs);
console_silent();
spin_unlock(&nmi_print_lock);
bust_spinlocks(0);
diff -Naur linux-2.5.44.orig/arch/i386/kernel/traps.c linux-2.5.44.lkcd/arch/i386/kernel/traps.c
--- linux-2.5.44.orig/arch/i386/kernel/traps.c Fri Oct 18 21:01:16 2002
+++ linux-2.5.44.lkcd/arch/i386/kernel/traps.c Sat Oct 19 12:39:15 2002
@@ -23,6 +23,7 @@
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/highmem.h>
+#include <linux/dump.h>

#ifdef CONFIG_EISA
#include <linux/ioport.h>
@@ -86,7 +87,6 @@

static int kstack_depth_to_print = 24;

-
/*
* If the address is either in the .text section of the
* kernel, or in the vmalloc'ed module regions, it *may*
@@ -295,6 +295,7 @@
handle_BUG(regs);
printk("%s: %04lx\n", str, err & 0xffff);
show_registers(regs);
+ dump((char *)str, regs);
bust_spinlocks(0);
spin_unlock_irq(&die_lock);
do_exit(SIGSEGV);
@@ -469,6 +470,23 @@
outb(reason, 0x61);
}

+#ifdef CONFIG_SMP
+int (*dump_ipi_function_ptr)(struct pt_regs *) = NULL;
+int dump_ipi(struct pt_regs *regs)
+{
+ if (!(dump_ipi_function_ptr && dump_ipi_function_ptr(regs))) {
+ return 0;
+ }
+ ack_APIC_irq();
+ return 1;
+}
+#else
+int dump_ipi(struct pt_regs *regs)
+{
+ return 0;
+}
+#endif
+
static void unknown_nmi_error(unsigned char reason, struct pt_regs * regs)
{
#ifdef CONFIG_MCA
@@ -530,6 +548,10 @@

++nmi_count(cpu);

+ if (dump_ipi(regs)) {
+ return;
+ }
+
if (!nmi_callback(regs, cpu))
default_do_nmi(regs);
}
@@ -925,3 +947,7 @@

trap_init_hook();
}
+
+#ifdef CONFIG_SMP
+EXPORT_SYMBOL(dump_ipi_function_ptr);
+#endif
diff -Naur linux-2.5.44.orig/arch/i386/mm/Makefile linux-2.5.44.lkcd/arch/i386/mm/Makefile
--- linux-2.5.44.orig/arch/i386/mm/Makefile Fri Oct 18 21:01:18 2002
+++ linux-2.5.44.lkcd/arch/i386/mm/Makefile Sat Oct 19 12:39:15 2002
@@ -2,7 +2,7 @@
# Makefile for the linux i386-specific parts of the memory manager.
#

-export-objs := pageattr.o
+export-objs := pageattr.o init.o

obj-y := init.o pgtable.o fault.o ioremap.o extable.o pageattr.o

diff -Naur linux-2.5.44.orig/arch/i386/mm/init.c linux-2.5.44.lkcd/arch/i386/mm/init.c
--- linux-2.5.44.orig/arch/i386/mm/init.c Fri Oct 18 21:02:27 2002
+++ linux-2.5.44.lkcd/arch/i386/mm/init.c Sat Oct 19 12:39:15 2002
@@ -19,6 +19,7 @@
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
+#include <linux/module.h>
#ifdef CONFIG_BLK_DEV_INITRD
#include <linux/blk.h>
#endif
@@ -157,7 +158,7 @@
return 0;
}

-static inline int page_is_ram(unsigned long pagenr)
+int page_is_ram (unsigned long pagenr)
{
int i;

@@ -600,3 +601,5 @@
}
}
#endif
+
+EXPORT_SYMBOL(page_is_ram);
diff -Naur linux-2.5.44.orig/init/main.c linux-2.5.44.lkcd/init/main.c
--- linux-2.5.44.orig/init/main.c Fri Oct 18 21:01:16 2002
+++ linux-2.5.44.lkcd/init/main.c Sat Oct 19 12:39:15 2002
@@ -87,6 +87,16 @@
int system_running = 0;

/*
+ * The kernel_magic value represents the address of _end, which allows
+ * namelist tools to "match" each other respectively. That way a tool
+ * that looks at /dev/mem can verify that it is using the right System.map
+ * file -- if kernel_magic doesn't equal the namelist value of _end,
+ * something's wrong.
+ */
+extern unsigned long _end;
+unsigned long *kernel_magic = &_end;
+
+/*
* Boot command-line arguments
*/
#define MAX_INIT_ARGS 8
diff -Naur linux-2.5.44.orig/kernel/Makefile linux-2.5.44.lkcd/kernel/Makefile
--- linux-2.5.44.orig/kernel/Makefile Fri Oct 18 21:01:17 2002
+++ linux-2.5.44.lkcd/kernel/Makefile Sat Oct 19 12:39:15 2002
@@ -3,7 +3,7 @@
#

export-objs = signal.o sys.o kmod.o workqueue.o ksyms.o pm.o exec_domain.o \
- printk.o platform.o suspend.o dma.o module.o cpufreq.o \
+ printk.o platform.o suspend.o dma.o module.o cpufreq.o panic.o \
profile.o rcupdate.o

obj-y = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
diff -Naur linux-2.5.44.orig/kernel/panic.c linux-2.5.44.lkcd/kernel/panic.c
--- linux-2.5.44.orig/kernel/panic.c Fri Oct 18 21:02:32 2002
+++ linux-2.5.44.lkcd/kernel/panic.c Sat Oct 19 12:39:15 2002
@@ -16,10 +16,15 @@
#include <linux/init.h>
#include <linux/sysrq.h>
#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/dump.h>

asmlinkage void sys_sync(void); /* it's really int */

int panic_timeout;
+int (*dump_function_ptr)(char *, struct pt_regs *) = 0;
+volatile int dump_in_progress = 0;
+volatile int dumping_cpu = 0;

struct notifier_block *panic_notifier_list;

@@ -48,6 +53,8 @@
#if defined(CONFIG_ARCH_S390)
unsigned long caller = (unsigned long) __builtin_return_address(0);
#endif
+ struct pt_regs regs;
+ get_current_regs(&regs);

bust_spinlocks(1);
va_start(args, fmt);
@@ -62,12 +69,16 @@
sys_sync();
bust_spinlocks(0);

+#if !defined(CONFIG_CRASH_DUMP) && !defined(CONFIG_CRASH_DUMP_MODULE)
#ifdef CONFIG_SMP
smp_send_stop();
#endif
+#endif

notifier_call_chain(&panic_notifier_list, 0, buf);

+ dump(buf, &regs);
+
if (panic_timeout > 0)
{
/*
@@ -125,3 +136,8 @@
}

int tainted = 0;
+
+EXPORT_SYMBOL(panic_timeout);
+EXPORT_SYMBOL(dump_function_ptr);
+EXPORT_SYMBOL(dump_in_progress);
+EXPORT_SYMBOL(dumping_cpu);
diff -Naur linux-2.5.44.orig/kernel/sched.c linux-2.5.44.lkcd/kernel/sched.c
--- linux-2.5.44.orig/kernel/sched.c Fri Oct 18 21:02:28 2002
+++ linux-2.5.44.lkcd/kernel/sched.c Sat Oct 19 12:39:15 2002
@@ -29,6 +29,7 @@
#include <linux/security.h>
#include <linux/notifier.h>
#include <linux/blkdev.h>
+#include <linux/dump.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/rcupdate.h>
@@ -956,6 +957,17 @@
int idx;

/*
+ * Note that this code is only for kernels with dumping
+ * enabled -- otherwise, something better should be put
+ * in place to avoid scheduling a task while dumping.
+ * Then this #if can be removed. Obviously, this can
+ * slow down scheduling ever so slightly.
+ */
+ if (unlikely(dump_in_progress)) {
+ goto dump_scheduling_disabled;
+ }
+
+ /*
* Test if we are atomic. Since do_exit() needs to call into
* schedule() atomically, we ignore that path for now.
* Otherwise, whine if we are scheduling when we should not be.
@@ -1045,6 +1057,24 @@
preempt_enable_no_resched();
if (test_thread_flag(TIF_NEED_RESCHED))
goto need_resched;
+ return;
+
+dump_scheduling_disabled:
+ {
+ int this_cpu;
+ /* make sure we assign our this_cpu ... */
+ if (!current->active_mm) BUG();
+ this_cpu = current_thread_info()->cpu;
+
+ /*
+ * If this is not the dumping cpu, then spin right here
+ * till the dump is complete
+ */
+ if (this_cpu != dumping_cpu) {
+ while (dump_in_progress);
+ }
+ }
+ return;
}

#ifdef CONFIG_PREEMPT
-
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