diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index f76d6f77dd5e5301f40406c928e79420b4f308cf..2b7c9b67931d6818d85d5066544172f2df8693ac 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -441,6 +441,37 @@ setundefined:
return 0;
}
+#ifdef CONFIG_KGDB_KDB
+void kdb_dump_stack_on_cpu(int cpu)
+{
+ if (cpu == raw_smp_processor_id() || !IS_ENABLED(CONFIG_SMP)) {
+ dump_stack();
+ return;
+ }
+
+ if (!(kgdb_info[cpu].exception_state & DCPU_IS_SLAVE)) {
+ kdb_printf("ERROR: Task on cpu %d didn't stop in the debugger\n",
+ cpu);
+ return;
+ }
+
+ /*
+ * In general, architectures don't support dumping the stack of a
+ * "running" process that's not the current one. From the point of
+ * view of the Linux, kernel processes that are looping in the kgdb
+ * slave loop are still "running". There's also no API (that actually
+ * works across all architectures) that can do a stack crawl based
+ * on registers passed as a parameter.
+ *
+ * Solve this conundrum by asking slave CPUs to do the backtrace
+ * themselves.
+ */
+ kgdb_info[cpu].exception_state |= DCPU_WANT_BT;
+ while (kgdb_info[cpu].exception_state & DCPU_WANT_BT)
+ cpu_relax();
+}
+#endif
+
/*
* Return true if there is a valid kgdb I/O module. Also if no
* debugger is attached a message can be printed to the console about
@@ -580,6 +611,9 @@ cpu_loop:
atomic_xchg(&kgdb_active, cpu);
break;
}
+ } else if (kgdb_info[cpu].exception_state & DCPU_WANT_BT) {
+ dump_stack();
+ kgdb_info[cpu].exception_state &= ~DCPU_WANT_BT;
} else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) {
if (!raw_spin_is_locked(&dbg_slave_lock))
goto return_normal;
diff --git a/kernel/debug/debug_core.h b/kernel/debug/debug_core.h
index b4a7c326d5464c5c22f3a64311aad813c10cbcee..cd22b5f68831cc4f52a029f6653478870cebeb3e 100644
--- a/kernel/debug/debug_core.h
+++ b/kernel/debug/debug_core.h
@@ -33,7 +33,7 @@ struct kgdb_state {
#define DCPU_WANT_MASTER 0x1 /* Waiting to become a master kgdb cpu */
#define DCPU_NEXT_MASTER 0x2 /* Transition from one master cpu to another */
#define DCPU_IS_SLAVE 0x4 /* Slave cpu enter exception */
-#define DCPU_SSTEP 0x8 /* CPU is single stepping */
+#define DCPU_WANT_BT 0x8 /* Slave cpu should backtrace then clear flag */
struct debuggerinfo_struct {
void *debuggerinfo;
@@ -76,6 +76,7 @@ extern int kdb_stub(struct kgdb_state *ks);
extern int kdb_parse(const char *cmdstr);
extern int kdb_common_init_state(struct kgdb_state *ks);
extern int kdb_common_deinit_state(void);
+extern void kdb_dump_stack_on_cpu(int cpu);
#else /* ! CONFIG_KGDB_KDB */
static inline int kdb_stub(struct kgdb_state *ks)
{
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 7e2379aa0a1e7a2247041b497e6d747a3e05bb04..4af48ac536259bda11c7cd7de59e0f8f3634c245 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -22,20 +22,15 @@
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);
- }
+
+ if (!addr && kdb_task_has_cpu(p))
+ kdb_dump_stack_on_cpu(kdb_process_cpu(p));
+ else
+ show_stack(p, addr);
+
console_loglevel = old_lvl;
kdb_trap_printk--;
}
@@ -78,12 +73,12 @@ static void kdb_show_stack(struct task_struct *p, void *addr)
*/
static int
-kdb_bt1(struct task_struct *p, unsigned long mask,
- int argcount, int btaprompt)
+kdb_bt1(struct task_struct *p, unsigned long mask, bool btaprompt)
{
- char buffer[2];
- if (kdb_getarea(buffer[0], (unsigned long)p) ||
- kdb_getarea(buffer[0], (unsigned long)(p+1)-1))
+ char ch;
+
+ if (kdb_getarea(ch, (unsigned long)p) ||
+ kdb_getarea(ch, (unsigned long)(p+1)-1))
return KDB_BADADDR;
if (!kdb_task_state(p, mask))
return 0;
@@ -91,22 +86,47 @@ kdb_bt1(struct task_struct *p, unsigned long mask,
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");
+ kdb_printf("Enter <q> to end, <cr> or <space> to continue:");
+ do {
+ ch = kdb_getchar();
+ } while (!strchr("\r\n q", ch));
+ kdb_printf("\n");
+
+ /* reset the pager */
+ kdb_nextline = 1;
+
+ if (ch == 'q')
return 1;
- }
}
touch_nmi_watchdog();
return 0;
}
+static void
+kdb_bt_cpu(unsigned long cpu)
+{
+ struct task_struct *kdb_tsk;
+
+ if (cpu >= num_possible_cpus() || !cpu_online(cpu)) {
+ kdb_printf("WARNING: no process for cpu %ld\n", cpu);
+ return;
+ }
+
+ /* If a CPU failed to round up we could be here */
+ kdb_tsk = KDB_TSK(cpu);
+ if (!kdb_tsk) {
+ kdb_printf("WARNING: no task for cpu %ld\n", cpu);
+ return;
+ }
+
+ kdb_set_current_task(kdb_tsk);
+ kdb_bt1(kdb_tsk, ~0UL, false);
+}
+
int
kdb_bt(int argc, const char **argv)
{
int diag;
- int argcount = 5;
int btaprompt = 1;
int nextarg;
unsigned long addr;
@@ -125,7 +145,7 @@ kdb_bt(int argc, const char **argv)
/* Run the active tasks first */
for_each_online_cpu(cpu) {
p = kdb_curr_task(cpu);
- if (kdb_bt1(p, mask, argcount, btaprompt))
+ if (kdb_bt1(p, mask, btaprompt))
return 0;
}
/* Now the inactive tasks */
@@ -134,7 +154,7 @@ kdb_bt(int argc, const char **argv)
return 0;
if (task_curr(p))
continue;
- if (kdb_bt1(p, mask, argcount, btaprompt))
+ if (kdb_bt1(p, mask, btaprompt))
return 0;
} kdb_while_each_thread(g, p);
} else if (strcmp(argv[0], "btp") == 0) {
@@ -148,7 +168,7 @@ kdb_bt(int argc, const char **argv)
p = find_task_by_pid_ns(pid, &init_pid_ns);
if (p) {
kdb_set_current_task(p);
- return kdb_bt1(p, ~0UL, argcount, 0);
+ return kdb_bt1(p, ~0UL, false);
}
kdb_printf("No process with pid == %ld found\n", pid);
return 0;
@@ -159,11 +179,10 @@ kdb_bt(int argc, const char **argv)
if (diag)
return diag;
kdb_set_current_task((struct task_struct *)addr);
- return kdb_bt1((struct task_struct *)addr, ~0UL, argcount, 0);
+ return kdb_bt1((struct task_struct *)addr, ~0UL, false);
} 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) {
@@ -171,35 +190,22 @@ kdb_bt(int argc, const char **argv)
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) {
- void *kdb_tsk = KDB_TSK(cpu);
-
- /* If a CPU failed to round up we could be here */
- if (!kdb_tsk) {
- kdb_printf("WARNING: no task for cpu %ld\n",
- cpu);
- continue;
+ kdb_bt_cpu(cpu);
+ } else {
+ /*
+ * Recursive use of kdb_parse, do not use argv after
+ * this point.
+ */
+ argv = NULL;
+ kdb_printf("btc: cpu status: ");
+ kdb_parse("cpu\n");
+ for_each_online_cpu(cpu) {
+ kdb_bt_cpu(cpu);
+ touch_nmi_watchdog();
}
-
- sprintf(buf, "btt 0x%px\n", kdb_tsk);
- kdb_parse(buf);
- touch_nmi_watchdog();
+ kdb_set_current_task(save_current_task);
}
- kdb_set_current_task(save_current_task);
return 0;
} else {
if (argc) {
@@ -211,7 +217,7 @@ kdb_bt(int argc, const char **argv)
kdb_show_stack(kdb_current_task, (void *)addr);
return 0;
} else {
- return kdb_bt1(kdb_current_task, ~0UL, argcount, 0);
+ return kdb_bt1(kdb_current_task, ~0UL, false);
}
}
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 3a5184eb6977d430f9df84493340ceaafe2cefde..8bcdded5d61fcc24f71473115254ebc4820d767f 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -49,14 +49,88 @@ static int kgdb_transition_check(char *buffer)
return 0;
}
-static int kdb_read_get_key(char *buffer, size_t bufsize)
+/**
+ * kdb_handle_escape() - validity check on an accumulated escape sequence.
+ * @buf: Accumulated escape characters to be examined. Note that buf
+ * is not a string, it is an array of characters and need not be
+ * nil terminated.
+ * @sz: Number of accumulated escape characters.
+ *
+ * Return: -1 if the escape sequence is unwanted, 0 if it is incomplete,
+ * otherwise it returns a mapped key value to pass to the upper layers.
+ */
+static int kdb_handle_escape(char *buf, size_t sz)
+{
+ char *lastkey = buf + sz - 1;
+
+ switch (sz) {
+ case 1:
+ if (*lastkey == '\e')
+ return 0;
+ break;
+
+ case 2: /* \e<something> */
+ if (*lastkey == '[')
+ return 0;
+ break;
+
+ case 3:
+ switch (*lastkey) {
+ case 'A': /* \e[A, up arrow */
+ return 16;
+ case 'B': /* \e[B, down arrow */
+ return 14;
+ case 'C': /* \e[C, right arrow */
+ return 6;
+ case 'D': /* \e[D, left arrow */
+ return 2;
+ case '1': /* \e[<1,3,4>], may be home, del, end */
+ case '3':
+ case '4':
+ return 0;
+ }
+ break;
+
+ case 4:
+ if (*lastkey == '~') {
+ switch (buf[2]) {
+ case '1': /* \e[1~, home */
+ return 1;
+ case '3': /* \e[3~, del */
+ return 4;
+ case '4': /* \e[4~, end */
+ return 5;
+ }
+ }
+ break;
+ }
+
+ return -1;
+}
+
+/**
+ * kdb_getchar() - Read a single character from a kdb console (or consoles).
+ *
+ * Other than polling the various consoles that are currently enabled,
+ * most of the work done in this function is dealing with escape sequences.
+ *
+ * An escape key could be the start of a vt100 control sequence such as \e[D
+ * (left arrow) or it could be a character in its own right. The standard
+ * method for detecting the difference is to wait for 2 seconds to see if there
+ * are any other characters. kdb is complicated by the lack of a timer service
+ * (interrupts are off), by multiple input sources. Escape sequence processing
+ * has to be done as states in the polling loop.
+ *
+ * Return: The key pressed or a control code derived from an escape sequence.
+ */
+char kdb_getchar(void)
{
#define ESCAPE_UDELAY 1000
#define ESCAPE_DELAY (2*1000000/ESCAPE_UDELAY) /* 2 seconds worth of udelays */
- char escape_data[5]; /* longest vt100 escape sequence is 4 bytes */
- char *ped = escape_data;
+ char buf[4]; /* longest vt100 escape sequence is 4 bytes */
+ char *pbuf = buf;
int escape_delay = 0;
- get_char_func *f, *f_escape = NULL;
+ get_char_func *f, *f_prev = NULL;
int key;
for (f = &kdb_poll_funcs[0]; ; ++f) {
@@ -65,109 +139,37 @@ static int kdb_read_get_key(char *buffer, size_t bufsize)
touch_nmi_watchdog();
f = &kdb_poll_funcs[0];
}
- if (escape_delay == 2) {
- *ped = '\0';
- ped = escape_data;
- --escape_delay;
- }
- if (escape_delay == 1) {
- key = *ped++;
- if (!*ped)
- --escape_delay;
- break;
- }
+
key = (*f)();
if (key == -1) {
if (escape_delay) {
udelay(ESCAPE_UDELAY);
- --escape_delay;
+ if (--escape_delay == 0)
+ return '\e';
}
continue;
}
- if (bufsize <= 2) {
- if (key == '\r')
- key = '\n';
- *buffer++ = key;
- *buffer = '\0';
- return -1;
- }
- if (escape_delay == 0 && key == '\e') {
+
+ /*
+ * When the first character is received (or we get a change
+ * input source) we set ourselves up to handle an escape
+ * sequences (just in case).
+ */
+ if (f_prev != f) {
+ f_prev = f;
+ pbuf = buf;
escape_delay = ESCAPE_DELAY;
- ped = escape_data;
- f_escape = f;
- }
- if (escape_delay) {
- *ped++ = key;
- if (f_escape != f) {
- escape_delay = 2;
- continue;
- }
- if (ped - escape_data == 1) {
- /* \e */
- continue;
- } else if (ped - escape_data == 2) {
- /* \e<something> */
- if (key != '[')
- escape_delay = 2;
- continue;
- } else if (ped - escape_data == 3) {
- /* \e[<something> */
- int mapkey = 0;
- switch (key) {
- case 'A': /* \e[A, up arrow */
- mapkey = 16;
- break;
- case 'B': /* \e[B, down arrow */
- mapkey = 14;
- break;
- case 'C': /* \e[C, right arrow */
- mapkey = 6;
- break;
- case 'D': /* \e[D, left arrow */
- mapkey = 2;
- break;
- case '1': /* dropthrough */
- case '3': /* dropthrough */
- /* \e[<1,3,4>], may be home, del, end */
- case '4':
- mapkey = -1;
- break;
- }
- if (mapkey != -1) {
- if (mapkey > 0) {
- escape_data[0] = mapkey;
- escape_data[1] = '\0';
- }
- escape_delay = 2;
- }
- continue;
- } else if (ped - escape_data == 4) {
- /* \e[<1,3,4><something> */
- int mapkey = 0;
- if (key == '~') {
- switch (escape_data[2]) {
- case '1': /* \e[1~, home */
- mapkey = 1;
- break;
- case '3': /* \e[3~, del */
- mapkey = 4;
- break;
- case '4': /* \e[4~, end */
- mapkey = 5;
- break;
- }
- }
- if (mapkey > 0) {
- escape_data[0] = mapkey;
- escape_data[1] = '\0';
- }
- escape_delay = 2;
- continue;
- }
}
- break; /* A key to process */
+
+ *pbuf++ = key;
+ key = kdb_handle_escape(buf, pbuf - buf);
+ if (key < 0) /* no escape sequence; return best character */
+ return buf[pbuf - buf == 2 ? 1 : 0];
+ if (key > 0)
+ return key;
}
- return key;
+
+ unreachable();
}
/*
@@ -188,17 +190,7 @@ static int kdb_read_get_key(char *buffer, size_t bufsize)
* function. It is not reentrant - it relies on the fact
* that while kdb is running on only one "master debug" cpu.
* Remarks:
- *
- * The buffer size must be >= 2. A buffer size of 2 means that the caller only
- * wants a single key.
- *
- * An escape key could be the start of a vt100 control sequence such as \e[D
- * (left arrow) or it could be a character in its own right. The standard
- * method for detecting the difference is to wait for 2 seconds to see if there
- * are any other characters. kdb is complicated by the lack of a timer service
- * (interrupts are off), by multiple input sources and by the need to sometimes
- * return after just one key. Escape sequence processing has to be done as
- * states in the polling loop.
+ * The buffer size must be >= 2.
*/
static char *kdb_read(char *buffer, size_t bufsize)
@@ -233,9 +225,7 @@ static char *kdb_read(char *buffer, size_t bufsize)
*cp = '\0';
kdb_printf("%s", buffer);
poll_again:
- key = kdb_read_get_key(buffer, bufsize);
- if (key == -1)
- return buffer;
+ key = kdb_getchar();
if (key != 9)
tab = 0;
switch (key) {
@@ -746,7 +736,7 @@ kdb_printit:
/* check for having reached the LINES number of printed lines */
if (kdb_nextline >= linecount) {
- char buf1[16] = "";
+ char ch;
/* Watch out for recursion here. Any routine that calls
* kdb_printf will come back through here. And kdb_read
@@ -781,39 +771,38 @@ kdb_printit:
if (logging)
printk("%s", moreprompt);
- kdb_read(buf1, 2); /* '2' indicates to return
- * immediately after getting one key. */
+ ch = kdb_getchar();
kdb_nextline = 1; /* Really set output line 1 */
/* empty and reset the buffer: */
kdb_buffer[0] = '\0';
next_avail = kdb_buffer;
size_avail = sizeof(kdb_buffer);
- if ((buf1[0] == 'q') || (buf1[0] == 'Q')) {
+ if ((ch == 'q') || (ch == 'Q')) {
/* user hit q or Q */
KDB_FLAG_SET(CMD_INTERRUPT); /* command interrupted */
KDB_STATE_CLEAR(PAGER);
/* end of command output; back to normal mode */
kdb_grepping_flag = 0;
kdb_printf("\n");
- } else if (buf1[0] == ' ') {
+ } else if (ch == ' ') {
kdb_printf("\r");
suspend_grep = 1; /* for this recursion */
- } else if (buf1[0] == '\n') {
+ } else if (ch == '\n' || ch == '\r') {
kdb_nextline = linecount - 1;
kdb_printf("\r");
suspend_grep = 1; /* for this recursion */
- } else if (buf1[0] == '/' && !kdb_grepping_flag) {
+ } else if (ch == '/' && !kdb_grepping_flag) {
kdb_printf("\r");
kdb_getstr(kdb_grep_string, KDB_GREP_STRLEN,
kdbgetenv("SEARCHPROMPT") ?: "search> ");
*strchrnul(kdb_grep_string, '\n') = '\0';
kdb_grepping_flag += KDB_GREPPING_FLAG_SEARCH;
suspend_grep = 1; /* for this recursion */
- } else if (buf1[0] && buf1[0] != '\n') {
- /* user hit something other than enter */
+ } else if (ch) {
+ /* user hit something unexpected */
suspend_grep = 1; /* for this recursion */
- if (buf1[0] != '/')
+ if (ch != '/')
kdb_printf(
"\nOnly 'q', 'Q' or '/' are processed at "
"more prompt, input ignored\n");
diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
index 2118d8258b7c9a3d66b917f10575f7b109b5d665..55d052061ef94f42683c21aece75feba49ec318c 100644
--- a/kernel/debug/kdb/kdb_private.h
+++ b/kernel/debug/kdb/kdb_private.h
@@ -210,6 +210,7 @@ extern void kdb_ps1(const struct task_struct *p);
extern void kdb_print_nameval(const char *name, unsigned long val);
extern void kdb_send_sig(struct task_struct *p, int sig);
extern void kdb_meminfo_proc_show(void);
+extern char kdb_getchar(void);
extern char *kdb_getstr(char *, size_t, const char *);
extern void kdb_gdb_state_pass(char *buf);