From df0036d117e6c9df36324e517728e33543065f9a Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 8 Jan 2015 15:46:55 -0600 Subject: kdb: Fix off by one error in kdb_cpu() There was a follow on replacement patch against the prior "kgdb: Timeout if secondary CPUs ignore the roundup". See: https://lkml.org/lkml/2015/1/7/442 This patch is the delta vs the patch that was committed upstream: * Fix an off-by-one error in kdb_cpu(). * Replace NR_CPUS with CONFIG_NR_CPUS to tell checkpatch that we really want a static limit. * Removed the "KGDB: " prefix from the pr_crit() in debug_core.c (kgdb-next contains a patch which introduced pr_fmt() to this file to the tag will now be applied automatically). Cc: Daniel Thompson Cc: Signed-off-by: Jason Wessel --- kernel/debug/debug_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/debug/debug_core.c') diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 07ce18ca71e0..ac5c0f9c7a20 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -604,7 +604,7 @@ return_normal: online_cpus) cpu_relax(); if (!time_left) - pr_crit("KGDB: Timed out waiting for secondary CPUs.\n"); + pr_crit("Timed out waiting for secondary CPUs.\n"); /* * At this point the primary processor is completely -- cgit v1.2.3 From 5516fd7b92a7c16b9111a88aaa1b13dd937d8ac5 Mon Sep 17 00:00:00 2001 From: Colin Cross Date: Wed, 28 Jan 2015 17:02:14 +0530 Subject: debug: prevent entering debug mode on panic/exception. On non-developer devices, kgdb prevents the device from rebooting after a panic. Incase of panics and exceptions, to allow the device to reboot, prevent entering debug mode to avoid getting stuck waiting for the user to interact with debugger. To avoid entering the debugger on panic/exception without any extra configuration, panic_timeout is being used which can be set via /proc/sys/kernel/panic at run time and CONFIG_PANIC_TIMEOUT sets the default value. Setting panic_timeout indicates that the user requested machine to perform unattended reboot after panic. We dont want to get stuck waiting for the user input incase of panic. Cc: Andrew Morton Cc: kgdb-bugreport@lists.sourceforge.net Cc: linux-kernel@vger.kernel.org Cc: Android Kernel Team Cc: John Stultz Cc: Sumit Semwal Signed-off-by: Colin Cross [Kiran: Added context to commit message. panic_timeout is used instead of break_on_panic and break_on_exception to honor CONFIG_PANIC_TIMEOUT Modified the commit as per community feedback] Signed-off-by: Kiran Raparthy Signed-off-by: Daniel Thompson Signed-off-by: Jason Wessel --- kernel/debug/debug_core.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'kernel/debug/debug_core.c') diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index ac5c0f9c7a20..0874e2edd275 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -696,6 +696,14 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) if (arch_kgdb_ops.enable_nmi) arch_kgdb_ops.enable_nmi(0); + /* + * Avoid entering the debugger if we were triggered due to an oops + * but panic_timeout indicates the system should automatically + * reboot on panic. We don't want to get stuck waiting for input + * on such systems, especially if its "just" an oops. + */ + if (signo != SIGTRAP && panic_timeout) + return 1; memset(ks, 0, sizeof(struct kgdb_state)); ks->cpu = raw_smp_processor_id(); @@ -828,6 +836,15 @@ static int kgdb_panic_event(struct notifier_block *self, unsigned long val, void *data) { + /* + * Avoid entering the debugger if we were triggered due to a panic + * We don't want to get stuck waiting for input from user in such case. + * panic_timeout indicates the system should automatically + * reboot on panic. + */ + if (panic_timeout) + return NOTIFY_DONE; + if (dbg_kdb_mode) kdb_printf("PANIC: %s\n", (char *)data); kgdb_breakpoint(); -- cgit v1.2.3