While rounding up CPUs via NMIs, its possible that a rounded up CPU
maybe holding a console port lock leading to kgdb master CPU stuck in
a deadlock during invocation of console write operations. So in order
to avoid such a deadlock, enable oops_in_progress prior to invocation
of console handlers.
Suggested-by: Petr Mladek <pmla...@suse.com>
Signed-off-by: Sumit Garg <sumit.g...@linaro.org>
---
kernel/debug/kdb/kdb_io.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 349dfcc..f848482 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -566,7 +566,17 @@ static void kdb_msg_write(char *msg, int msg_len)
for_each_console(c) {
if (!(c->flags & CON_ENABLED))
continue;
+ /*
+ * While rounding up CPUs via NMIs, its possible that
+ * a rounded up CPU maybe holding a console port lock
+ * leading to kgdb master CPU stuck in a deadlock during
+ * invocation of console write operations. So in order
+ * to avoid such a deadlock, enable oops_in_progress
+ * prior to invocation of console handlers.
+ */
+ ++oops_in_progress;
c->write(c, msg, msg_len);
+ --oops_in_progress;
touch_nmi_watchdog();
}
}
--
2.7.4
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