Messages in this thread | | | Date | Wed, 26 Nov 2014 15:00:10 +0530 | Subject | Re: [RFC v3] debug: prevent entering debug mode on errors | From | Kiran Raparthy <> |
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On 26 November 2014 at 14:56, Daniel Thompson <daniel.thompson@linaro.org> wrote: > 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> Sure. Regards, Kiran > >> --- >> 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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