From: Douglas Anderson <dianders@chromium.org>
Date: Thu, 7 May 2020 20:08:44 +0000 (-0700)
Subject: kgdb: Prevent infinite recursive entries to the debugger
X-Git-Tag: v5.8-rc1~170^2~11
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3ca676e4ca60d1834bb77535dafe24169cadacef;p=thirdparty%2Flinux.git

kgdb: Prevent infinite recursive entries to the debugger

If we detect that we recursively entered the debugger we should hack
our I/O ops to NULL so that the panic() in the next line won't
actually cause another recursion into the debugger.  The first line of
kgdb_panic() will check this and return.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Link: https://lore.kernel.org/r/20200507130644.v4.6.I89de39f68736c9de610e6f241e68d8dbc44bc266@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
---

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 1cd8e8b41115b..e2d67b163fb63 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -530,6 +530,7 @@ static int kgdb_reenter_check(struct kgdb_state *ks)
 
 	if (exception_level > 1) {
 		dump_stack();
+		kgdb_io_module_registered = false;
 		panic("Recursive entry to debugger");
 	}