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authorDouglas Anderson <dianders@chromium.org>2019-09-25 13:02:19 -0700
committerDaniel Thompson <daniel.thompson@linaro.org>2019-10-10 16:28:14 +0100
commit55a7e23f461fc2c321d7efcdeca1750085e9323f (patch)
treedc737299227f925508a3f5ed2d4ac4bad3149e52
parent54af3e39eed7d77f0923511f3c7f446e7d477635 (diff)
downloadlinux-55a7e23f461fc2c321d7efcdeca1750085e9323f.tar.gz
kdb: Fix "btc <cpu>" crash if the CPU didn't round up
I noticed that when I did "btc <cpu>" and the CPU I passed in hadn't rounded up that I'd crash. I was going to copy the same fix from commit 162bc7f5afd7 ("kdb: Don't back trace on a cpu that didn't round up") into the "not all the CPUs" case, but decided it'd be better to clean things up a little bit. This consolidates the two code paths. It is _slightly_ wasteful in in that the checks for "cpu" being too small or being offline isn't really needed when we're iterating over all online CPUs, but that really shouldn't hurt. Better to have the same code path. While at it, eliminate at least one slightly ugly (and totally needless) recursive use of kdb_parse(). Signed-off-by: Douglas Anderson <dianders@chromium.org> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
-rw-r--r--kernel/debug/kdb/kdb_bt.c61
1 files changed, 34 insertions, 27 deletions
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 120fc686c919..d9af139f9a31 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -101,6 +101,27 @@ kdb_bt1(struct task_struct *p, unsigned long mask, bool btaprompt)
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)
{
@@ -161,7 +182,6 @@ kdb_bt(int argc, const char **argv)
} 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) {
@@ -169,35 +189,22 @@ 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) {