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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	[thread overview]
Message-ID: <20200507130644.v4.6.I89de39f68736c9de610e6f241e68d8dbc44bc266@changeid> (raw)
In-Reply-To: <20200507200850.60646-1-dianders@chromium.org>

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


  parent reply	other threads:[~2020-05-07 20:09 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-07 20:08 [PATCH v4 00/12] kgdb: Support late serial drivers; enable early debug w/ boot consoles Douglas Anderson
2020-05-07 20:08 ` [PATCH v4 01/12] kgdb: Disable WARN_CONSOLE_UNLOCKED for all kgdb Douglas Anderson
2020-05-07 20:08 ` [PATCH v4 02/12] Revert "kgdboc: disable the console lock when in kgdb" Douglas Anderson
2020-05-07 20:08 ` [PATCH v4 03/12] kgdboc: Use a platform device to handle tty drivers showing up late Douglas Anderson
2020-05-18 16:46   ` Daniel Thompson
2020-05-07 20:08 ` [PATCH v4 04/12] kgdb: Delay "kgdbwait" to dbg_late_init() by default Douglas Anderson
2020-05-15 16:18   ` Daniel Thompson
2020-05-07 20:08 ` [PATCH v4 05/12] arm64: Add call_break_hook() to early_brk64() for early kgdb Douglas Anderson
2020-05-13 23:12   ` Doug Anderson
2020-05-07 20:08 ` Douglas Anderson [this message]
2020-05-07 20:08 ` [PATCH v4 07/12] kgdboc: Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdboc Douglas Anderson
2020-05-11 16:02   ` Daniel Thompson
2020-05-07 20:08 ` [PATCH v4 08/12] kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles Douglas Anderson
2020-05-07 20:08 ` [PATCH v4 09/12] Documentation: kgdboc: Document new kgdboc_earlycon parameter Douglas Anderson
2020-05-07 20:08 ` [PATCH v4 10/12] serial: qcom_geni_serial: Support kgdboc_earlycon Douglas Anderson
2020-05-07 20:08 ` [PATCH v4 11/12] serial: 8250_early: " Douglas Anderson
2020-05-07 20:08 ` [PATCH v4 12/12] serial: amba-pl011: " Douglas Anderson
2020-05-14 16:21 ` [PATCH v4 00/12] kgdb: Support late serial drivers; enable early debug w/ boot consoles Daniel Thompson
2020-05-14 16:34   ` Doug Anderson
2020-05-14 16:36     ` Greg Kroah-Hartman
2020-05-19 10:37       ` Daniel Thompson
2020-05-19 10:36 ` Daniel Thompson

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