| Message ID | 1416993266-16514-1-git-send-email-kiran.kumar@linaro.org |
|---|---|
| State | New |
| Headers | show |
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(); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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(); >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On 26/11/14 17:45, Colin Cross wrote: > On Wed, Nov 26, 2014 at 1:14 AM, Kiran Raparthy <kiran.kumar@linaro.org> 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> >> --- >> 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(); > > The original patch was more useful as it allowed re-enabling break on > panic on specific devices where you were trying to debug a > reproducible issue. What about using a module_param similar to > kgdbreboot, but setting the default based on CONFIG_PANIC_TIMEOUT to > avoid extra configuration? This change was due to my review so perhaps I'd better answer this... panic_timeout is the value of the panic sysctl. In addition to the normal sysctl tooling (which I don't think is available on most android systems), its value can be set using panic=0 on the kernel command line or via /proc/sys/kernel/panic at runtime. CONFIG_PANIC_TIMEOUT merely sets the default value of the sysctl. I guess perhaps the patch description could be improved to make this clearer. Therefore, the only loss of function I expected versus the original is that it would be hard to get as far as a reproducible panic if the system also has a ton of reproducible oopses that we don't want to fix. Is such a use-case important? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Hi Jason, On 27 November 2014 at 15:19, Daniel Thompson <daniel.thompson@linaro.org> wrote: > On 26/11/14 17:45, Colin Cross wrote: >> On Wed, Nov 26, 2014 at 1:14 AM, Kiran Raparthy <kiran.kumar@linaro.org> 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> >>> --- >>> 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(); >> >> The original patch was more useful as it allowed re-enabling break on >> panic on specific devices where you were trying to debug a >> reproducible issue. What about using a module_param similar to >> kgdbreboot, but setting the default based on CONFIG_PANIC_TIMEOUT to >> avoid extra configuration? > > This change was due to my review so perhaps I'd better answer this... > > panic_timeout is the value of the panic sysctl. In addition to the > normal sysctl tooling (which I don't think is available on most android > systems), its value can be set using panic=0 on the kernel command line > or via /proc/sys/kernel/panic at runtime. > > CONFIG_PANIC_TIMEOUT merely sets the default value of the sysctl. I > guess perhaps the patch description could be improved to make this clearer. > > Therefore, the only loss of function I expected versus the original is > that it would be hard to get as far as a reproducible panic if the > system also has a ton of reproducible oopses that we don't want to fix. > Is such a use-case important? Could you please let me know if this patch is good to move from RFC to PATCH? Regards, Kiran -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Hi Jason, On 1 December 2014 at 11:32, Kiran Raparthy <kiran.kumar@linaro.org> wrote: > Hi Jason, > > On 27 November 2014 at 15:19, Daniel Thompson > <daniel.thompson@linaro.org> wrote: >> On 26/11/14 17:45, Colin Cross wrote: >>> On Wed, Nov 26, 2014 at 1:14 AM, Kiran Raparthy <kiran.kumar@linaro.org> 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> >>>> --- >>>> 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(); >>> >>> The original patch was more useful as it allowed re-enabling break on >>> panic on specific devices where you were trying to debug a >>> reproducible issue. What about using a module_param similar to >>> kgdbreboot, but setting the default based on CONFIG_PANIC_TIMEOUT to >>> avoid extra configuration? >> >> This change was due to my review so perhaps I'd better answer this... >> >> panic_timeout is the value of the panic sysctl. In addition to the >> normal sysctl tooling (which I don't think is available on most android >> systems), its value can be set using panic=0 on the kernel command line >> or via /proc/sys/kernel/panic at runtime. >> >> CONFIG_PANIC_TIMEOUT merely sets the default value of the sysctl. I >> guess perhaps the patch description could be improved to make this clearer. >> >> Therefore, the only loss of function I expected versus the original is >> that it would be hard to get as far as a reproducible panic if the >> system also has a ton of reproducible oopses that we don't want to fix. >> Is such a use-case important? > > Could you please let me know if this patch is good to move from RFC to PATCH? Just a gentle reminder. Regards, Kiran > Regards, > Kiran -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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();