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From:   Douglas Anderson <dianders@chromium.org>
To:     jason.wessel@windriver.com, daniel.thompson@linaro.org,
        gregkh@linuxfoundation.org
Cc:     corbet@lwn.net, frowand.list@gmail.com, bjorn.andersson@linaro.org,
        linux-serial@vger.kernel.org, mingo@redhat.com, hpa@zytor.com,
        jslaby@suse.com, kgdb-bugreport@lists.sourceforge.net,
        sumit.garg@linaro.org, will@kernel.org, tglx@linutronix.de,
        agross@kernel.org, catalin.marinas@arm.com, bp@alien8.de,
        Douglas Anderson <dianders@chromium.org>,
        linux-kernel@vger.kernel.org
Subject: [PATCH v4 06/12] kgdb: Prevent infinite recursive entries to the debugger
Date:   Thu,  7 May 2020 13:08:44 -0700
Message-Id: <20200507130644.v4.6.I89de39f68736c9de610e6f241e68d8dbc44bc266@changeid>
In-Reply-To: <20200507200850.60646-1-dianders@chromium.org>
References: <20200507200850.60646-1-dianders@chromium.org>
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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>
---

Changes in v4: None
Changes in v3:
- ("kgdb: Prevent infinite recursive entries to the debugger") new for v3.

Changes in v2: None

 kernel/debug/debug_core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 503c1630ca76..faf5bd4c34ee 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -532,6 +532,7 @@ 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");
 	}
 
-- 
2.26.2.645.ge9eca65c58-goog