From 3818c29a65d6af5d53a977a4078d8cc94eb553e8 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Tue, 4 Dec 2018 19:38:28 -0800 Subject: kdb: Don't back trace on a cpu that didn't round up [ Upstream commit 162bc7f5afd75b72acbe3c5f3488ef7e64a3fe36 ] If you have a CPU that fails to round up and then run 'btc' you'll end up crashing in kdb becaue we dereferenced NULL. Let's add a check. It's wise to also set the task to NULL when leaving the debugger so that if we fail to round up on a later entry into the debugger we won't backtrace a stale task. Signed-off-by: Douglas Anderson Acked-by: Daniel Thompson Signed-off-by: Daniel Thompson Signed-off-by: Sasha Levin --- kernel/debug/debug_core.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/debug/debug_core.c') diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 65c0f1363788..94aa9ae0007a 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -535,6 +535,8 @@ return_normal: arch_kgdb_ops.correct_hw_break(); if (trace_on) tracing_on(); + kgdb_info[cpu].debuggerinfo = NULL; + kgdb_info[cpu].task = NULL; kgdb_info[cpu].exception_state &= ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); kgdb_info[cpu].enter_kgdb--; @@ -667,6 +669,8 @@ kgdb_restore: if (trace_on) tracing_on(); + kgdb_info[cpu].debuggerinfo = NULL; + kgdb_info[cpu].task = NULL; kgdb_info[cpu].exception_state &= ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE); kgdb_info[cpu].enter_kgdb--; -- cgit v1.2.3