linux-kernel - [PATCH AUTOSEL 4.19 019/106] kgdb: Prevent infinite recursive entries to the debugger

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200608232238.3368589-19-sashal@kernel.org>
Date:   Mon,  8 Jun 2020 19:21:11 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Douglas Anderson <dianders@...omium.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Sasha Levin <sashal@...nel.org>,
        kgdb-bugreport@...ts.sourceforge.net
Subject: [PATCH AUTOSEL 4.19 019/106] kgdb: Prevent infinite recursive entries to the debugger

From: Douglas Anderson <dianders@...omium.org>

[ Upstream commit 3ca676e4ca60d1834bb77535dafe24169cadacef ]

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@...omium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@...aro.org>
Link: https://lore.kernel.org/r/20200507130644.v4.6.I89de39f68736c9de610e6f241e68d8dbc44bc266@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@...aro.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 d2799767aab8..6a1dc2613bb9 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -444,6 +444,7 @@ 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");
 	}
 
-- 
2.25.1