Messages in this thread | | | Date | Wed, 26 Nov 2014 09:26:14 +0000 | From | Daniel Thompson <> | Subject | Re: [RFC v3] debug: prevent entering debug mode on errors |
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On 26/11/14 09:14, Kiran Raparthy wrote: > From: Colin Cross <ccross@android.com> > > debug: prevent entering debug mode on errors > > On non-developer devices kgdb prevents CONFIG_PANIC_TIMEOUT from rebooting the > device after a panic. > > In case of panics and exceptions, to honor CONFIG_PANIC_TIMEOUT, prevent > entering debug mode to avoid getting stuck waiting for the user to interact > with debugger. > > Cc: Jason Wessel <jason.wessel@windriver.com> > Cc: kgdb-bugreport@lists.sourceforge.net > Cc: linux-kernel@vger.kernel.org > Cc: Android Kernel Team <kernel-team@android.com> > Cc: John Stultz <john.stultz@linaro.org> > Cc: Sumit Semwal <sumit.semwal@linaro.org> > Signed-off-by: Colin Cross <ccross@android.com> > [Kiran: Added context to commit message. > panic_timeout is used instead of break_on_panic and > break_on_exception to honor CONFIG_PANIC_TIMEOUT] > Signed-off-by: Kiran Raparthy <kiran.kumar@linaro.org>
When this gets upgrade from RFC to PATCH then feel free to add: Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
> --- > kernel/debug/debug_core.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c > index 1adf62b..0012a1f 100644 > --- a/kernel/debug/debug_core.c > +++ b/kernel/debug/debug_core.c > @@ -689,6 +689,14 @@ 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(); > @@ -821,6 +829,15 @@ 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(); >
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