On Tue, 27 Nov 2018 15:15:20 +0800 Feng Tang <[email protected]> wrote:
> Kernel panic issues are always painful to debug, partially > because it's not easy to get enough information of the > context when panic happens. > > And we have ramoops and kdump for that, while this commit > tries to provide a easier way to show the system info by adding > a cmdline parameter, referring some idea from sysrq handler. > > Signed-off-by: Feng Tang <[email protected]> > Cc: Thomas Gleixner <[email protected]> > Cc: John Stultz <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Steven Rostedt <[email protected]> > --- > Changelog: > v2: > - change text "dump/DUMP" to "print/PRINT" which > is more accurate, suggested by Andrew Morton > - add code to print ftrace buffer > > Documentation/admin-guide/kernel-parameters.txt | 8 +++++++ > kernel/panic.c | 28 > +++++++++++++++++++++++++ > 2 files changed, 36 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt > b/Documentation/admin-guide/kernel-parameters.txt > index 19f4423..80c819a 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -3081,6 +3081,14 @@ > timeout < 0: reboot immediately > Format: <timeout> > > + panic_print= Bitmask for printing system info when panic happens. > + User can chose combination of the following bits: > + bit 0: print all tasks info > + bit 1: print system memory info > + bit 2: print timer info > + bit 3: print locks info if CONFIG_LOCKDEP is on > + bit 4: print ftrace buffer Note, "ftrace_dump_on_oops" accomplishes the same thing. Should this be a sysctl setting as well? -- Steve > + > panic_on_warn panic() instead of WARN(). Useful to cause kdump > on a WARN(). > > diff --git a/kernel/panic.c b/kernel/panic.c > index f6d549a..fb6ccd1 100644 > --- a/kernel/panic.c > +++ b/kernel/panic.c > @@ -45,6 +45,13 @@ int panic_on_warn __read_mostly; > int panic_timeout = CONFIG_PANIC_TIMEOUT; > EXPORT_SYMBOL_GPL(panic_timeout); > > +#define PANIC_PRINT_TASK_INFO 0x00000001 > +#define PANIC_PRINT_MEM_INFO 0x00000002 > +#define PANIC_PRINT_TIMER_INFO 0x00000004 > +#define PANIC_PRINT_LOCK_INFO 0x00000008 > +#define PANIC_PRINT_FTRACE_INFO 0x00000010 > +static unsigned long panic_print; > + > ATOMIC_NOTIFIER_HEAD(panic_notifier_list); > > EXPORT_SYMBOL(panic_notifier_list); > @@ -124,6 +131,24 @@ void nmi_panic(struct pt_regs *regs, const char *msg) > } > EXPORT_SYMBOL(nmi_panic); > > +static void panic_print_sys_info(void) > +{ > + if (panic_print & PANIC_PRINT_TASK_INFO) > + show_state(); > + > + if (panic_print & PANIC_PRINT_MEM_INFO) > + show_mem(0, NULL); > + > + if (panic_print & PANIC_PRINT_TIMER_INFO) > + sysrq_timer_list_show(); > + > + if (panic_print & PANIC_PRINT_LOCK_INFO) > + debug_show_all_locks(); > + > + if (panic_print & PANIC_PRINT_FTRACE_INFO) > + ftrace_dump(DUMP_ALL); > +} > + > /** > * panic - halt the system > * @fmt: The text string to print > @@ -250,6 +275,8 @@ void panic(const char *fmt, ...) > debug_locks_off(); > console_flush_on_panic(); > > + panic_print_sys_info(); > + > if (!panic_blink) > panic_blink = no_blink; > > @@ -654,6 +681,7 @@ void refcount_error_report(struct pt_regs *regs, const > char *err) > #endif > > core_param(panic, panic_timeout, int, 0644); > +core_param(panic_print, panic_print, ulong, 0644); > core_param(pause_on_oops, pause_on_oops, int, 0644); > core_param(panic_on_warn, panic_on_warn, int, 0644); > core_param(crash_kexec_post_notifiers, crash_kexec_post_notifiers, bool, > 0644);
