From: Colin Cross <ccr...@android.com>
debug: prevent entering debug mode on errors
On non-developer devices kgdb prevents CONFIG_PANIC_TIMEOUT from rebooting the
device after a panic.
In case of panics and exceptions, to honor CONFIG_PANIC_TIMEOUT, prevent
entering debug mode to avoid getting stuck waiting for the user to interact
with debugger.
Cc: Jason Wessel <jason.wes...@windriver.com>
Cc: kgdb-bugrep...@lists.sourceforge.net
Cc: linux-kernel@vger.kernel.org
Cc: Android Kernel Team <kernel-t...@android.com>
Cc: John Stultz <john.stu...@linaro.org>
Cc: Sumit Semwal <sumit.sem...@linaro.org>
Signed-off-by: Colin Cross <ccr...@android.com>
[Kiran: Added context to commit message.
panic_timeout is used instead of break_on_panic and
break_on_exception to honor CONFIG_PANIC_TIMEOUT]
Signed-off-by: Kiran Raparthy <kiran.ku...@linaro.org>
---
kernel/debug/debug_core.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 1adf62b..0012a1f 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -689,6 +689,14 @@ kgdb_handle_exception(int evector, int signo, int ecode,
struct pt_regs *regs)
if (arch_kgdb_ops.enable_nmi)
arch_kgdb_ops.enable_nmi(0);
+ /*
+ * Avoid entering the debugger if we were triggered due to an oops
+ * but panic_timeout indicates the system should automatically
+ * reboot on panic. We don't want to get stuck waiting for input
+ * on such systems, especially if its "just" an oops.
+ */
+ if (signo != SIGTRAP && panic_timeout)
+ return 1;
memset(ks, 0, sizeof(struct kgdb_state));
ks->cpu = raw_smp_processor_id();
@@ -821,6 +829,15 @@ static int kgdb_panic_event(struct notifier_block *self,
unsigned long val,
void *data)
{
+ /*
+ * Avoid entering the debugger if we were triggered due to a panic
+ * We don't want to get stuck waiting for input from user in such case.
+ * panic_timeout indicates the system should automatically
+ * reboot on panic.
+ */
+ if (panic_timeout)
+ return NOTIFY_DONE;
+
if (dbg_kdb_mode)
kdb_printf("PANIC: %s\n", (char *)data);
kgdb_breakpoint();
--
1.8.2.1
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