v4.19.13 snapshot.
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
new file mode 100644
index 0000000..7921ae4
--- /dev/null
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -0,0 +1,211 @@
+/*
+ * Kernel Debugger Architecture Independent Stack Traceback
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 1999-2004 Silicon Graphics, Inc. All Rights Reserved.
+ * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
+ */
+
+#include <linux/ctype.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/debug.h>
+#include <linux/kdb.h>
+#include <linux/nmi.h>
+#include "kdb_private.h"
+
+
+static void kdb_show_stack(struct task_struct *p, void *addr)
+{
+ int old_lvl = console_loglevel;
+ console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
+ kdb_trap_printk++;
+ kdb_set_current_task(p);
+ if (addr) {
+ show_stack((struct task_struct *)p, addr);
+ } else if (kdb_current_regs) {
+#ifdef CONFIG_X86
+ show_stack(p, &kdb_current_regs->sp);
+#else
+ show_stack(p, NULL);
+#endif
+ } else {
+ show_stack(p, NULL);
+ }
+ console_loglevel = old_lvl;
+ kdb_trap_printk--;
+}
+
+/*
+ * kdb_bt
+ *
+ * This function implements the 'bt' command. Print a stack
+ * traceback.
+ *
+ * bt [<address-expression>] (addr-exp is for alternate stacks)
+ * btp <pid> Kernel stack for <pid>
+ * btt <address-expression> Kernel stack for task structure at
+ * <address-expression>
+ * bta [DRSTCZEUIMA] All useful processes, optionally
+ * filtered by state
+ * btc [<cpu>] The current process on one cpu,
+ * default is all cpus
+ *
+ * bt <address-expression> refers to a address on the stack, that location
+ * is assumed to contain a return address.
+ *
+ * btt <address-expression> refers to the address of a struct task.
+ *
+ * Inputs:
+ * argc argument count
+ * argv argument vector
+ * Outputs:
+ * None.
+ * Returns:
+ * zero for success, a kdb diagnostic if error
+ * Locking:
+ * none.
+ * Remarks:
+ * Backtrack works best when the code uses frame pointers. But even
+ * without frame pointers we should get a reasonable trace.
+ *
+ * mds comes in handy when examining the stack to do a manual traceback or
+ * to get a starting point for bt <address-expression>.
+ */
+
+static int
+kdb_bt1(struct task_struct *p, unsigned long mask,
+ int argcount, int btaprompt)
+{
+ char buffer[2];
+ if (kdb_getarea(buffer[0], (unsigned long)p) ||
+ kdb_getarea(buffer[0], (unsigned long)(p+1)-1))
+ return KDB_BADADDR;
+ if (!kdb_task_state(p, mask))
+ return 0;
+ kdb_printf("Stack traceback for pid %d\n", p->pid);
+ kdb_ps1(p);
+ kdb_show_stack(p, NULL);
+ if (btaprompt) {
+ kdb_getstr(buffer, sizeof(buffer),
+ "Enter <q> to end, <cr> to continue:");
+ if (buffer[0] == 'q') {
+ kdb_printf("\n");
+ return 1;
+ }
+ }
+ touch_nmi_watchdog();
+ return 0;
+}
+
+int
+kdb_bt(int argc, const char **argv)
+{
+ int diag;
+ int argcount = 5;
+ int btaprompt = 1;
+ int nextarg;
+ unsigned long addr;
+ long offset;
+
+ /* Prompt after each proc in bta */
+ kdbgetintenv("BTAPROMPT", &btaprompt);
+
+ if (strcmp(argv[0], "bta") == 0) {
+ struct task_struct *g, *p;
+ unsigned long cpu;
+ unsigned long mask = kdb_task_state_string(argc ? argv[1] :
+ NULL);
+ if (argc == 0)
+ kdb_ps_suppressed();
+ /* Run the active tasks first */
+ for_each_online_cpu(cpu) {
+ p = kdb_curr_task(cpu);
+ if (kdb_bt1(p, mask, argcount, btaprompt))
+ return 0;
+ }
+ /* Now the inactive tasks */
+ kdb_do_each_thread(g, p) {
+ if (KDB_FLAG(CMD_INTERRUPT))
+ return 0;
+ if (task_curr(p))
+ continue;
+ if (kdb_bt1(p, mask, argcount, btaprompt))
+ return 0;
+ } kdb_while_each_thread(g, p);
+ } else if (strcmp(argv[0], "btp") == 0) {
+ struct task_struct *p;
+ unsigned long pid;
+ if (argc != 1)
+ return KDB_ARGCOUNT;
+ diag = kdbgetularg((char *)argv[1], &pid);
+ if (diag)
+ return diag;
+ p = find_task_by_pid_ns(pid, &init_pid_ns);
+ if (p) {
+ kdb_set_current_task(p);
+ return kdb_bt1(p, ~0UL, argcount, 0);
+ }
+ kdb_printf("No process with pid == %ld found\n", pid);
+ return 0;
+ } else if (strcmp(argv[0], "btt") == 0) {
+ if (argc != 1)
+ return KDB_ARGCOUNT;
+ diag = kdbgetularg((char *)argv[1], &addr);
+ if (diag)
+ return diag;
+ kdb_set_current_task((struct task_struct *)addr);
+ return kdb_bt1((struct task_struct *)addr, ~0UL, argcount, 0);
+ } else if (strcmp(argv[0], "btc") == 0) {
+ unsigned long cpu = ~0;
+ struct task_struct *save_current_task = kdb_current_task;
+ char buf[80];
+ if (argc > 1)
+ return KDB_ARGCOUNT;
+ if (argc == 1) {
+ diag = kdbgetularg((char *)argv[1], &cpu);
+ if (diag)
+ return diag;
+ }
+ /* Recursive use of kdb_parse, do not use argv after
+ * this point */
+ argv = NULL;
+ if (cpu != ~0) {
+ if (cpu >= num_possible_cpus() || !cpu_online(cpu)) {
+ kdb_printf("no process for cpu %ld\n", cpu);
+ return 0;
+ }
+ sprintf(buf, "btt 0x%px\n", KDB_TSK(cpu));
+ kdb_parse(buf);
+ return 0;
+ }
+ kdb_printf("btc: cpu status: ");
+ kdb_parse("cpu\n");
+ for_each_online_cpu(cpu) {
+ sprintf(buf, "btt 0x%px\n", KDB_TSK(cpu));
+ kdb_parse(buf);
+ touch_nmi_watchdog();
+ }
+ kdb_set_current_task(save_current_task);
+ return 0;
+ } else {
+ if (argc) {
+ nextarg = 1;
+ diag = kdbgetaddrarg(argc, argv, &nextarg, &addr,
+ &offset, NULL);
+ if (diag)
+ return diag;
+ kdb_show_stack(kdb_current_task, (void *)addr);
+ return 0;
+ } else {
+ return kdb_bt1(kdb_current_task, ~0UL, argcount, 0);
+ }
+ }
+
+ /* NOTREACHED */
+ return 0;
+}