Messages in this thread Patch in this message | | | Date | Tue, 6 Jun 2006 22:59:43 +0900 | From | "Akiyama, Nobuyuki" <> | Subject | Re: [Fastboot] [RFC][PATCH] Add missing notifier before crashing |
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On Tue, 6 Jun 2006 20:08:37 +0900 "Akiyama, Nobuyuki" <akiyama.nobuyuk@jp.fujitsu.com> wrote:
> > To handle the contradiction of adding crash notifier to kexec and > > maintaining kexec reliability > > I suggest adding a flag to Kconfig > > ENABLE_CRASH_NOTIFIER > > > > This removes any code in the critical path for people not needing crash > > notification. > > I am just thinking same thing, but one point is different. > To select policy by Kconfig is not flexible. If we want to change policy, > we have to rebuild the kernel. I don't think that distributors release > the kernels for each policy. > > Instead of Kconfig, how about using proc filesystem. e.g. kdump_safe. > If kdump_safe is 1, crash notifier will not be called. > If kdump_safe is 0, crash notifier will be called.
I attach a sample patch for help to discuss.
diff -Nurp linux-2.6.17-rc6/arch/i386/kernel/traps.c linux-2.6.17-rc6.mod/arch/i386/kernel/traps.c --- linux-2.6.17-rc6/arch/i386/kernel/traps.c 2006-06-06 22:47:38.000000000 +0900 +++ linux-2.6.17-rc6.mod/arch/i386/kernel/traps.c 2006-06-06 22:51:01.000000000 +0900 @@ -414,7 +414,7 @@ void die(const char * str, struct pt_reg return; if (kexec_should_crash(current)) - crash_kexec(regs); + crash_kexec(CRASH_ON_DIE, regs, NULL); if (in_interrupt()) panic("Fatal exception in interrupt"); @@ -665,7 +665,7 @@ void die_nmi (struct pt_regs *regs, cons */ if (!user_mode_vm(regs)) { current->thread.trap_no = 2; - crash_kexec(regs); + crash_kexec(CRASH_ON_DIE, regs, NULL); } do_exit(SIGSEGV); diff -Nurp linux-2.6.17-rc6/arch/powerpc/kernel/traps.c linux-2.6.17-rc6.mod/arch/powerpc/kernel/traps.c --- linux-2.6.17-rc6/arch/powerpc/kernel/traps.c 2006-06-06 22:47:39.000000000 +0900 +++ linux-2.6.17-rc6.mod/arch/powerpc/kernel/traps.c 2006-06-06 22:51:01.000000000 +0900 @@ -132,7 +132,7 @@ int die(const char *str, struct pt_regs if (!crash_dump_start && kexec_should_crash(current)) { crash_dump_start = 1; spin_unlock_irq(&die_lock); - crash_kexec(regs); + crash_kexec(CRASH_ON_DIE, regs, NULL); /* NOTREACHED */ } spin_unlock_irq(&die_lock); diff -Nurp linux-2.6.17-rc6/arch/x86_64/kernel/traps.c linux-2.6.17-rc6.mod/arch/x86_64/kernel/traps.c --- linux-2.6.17-rc6/arch/x86_64/kernel/traps.c 2006-06-06 22:47:40.000000000 +0900 +++ linux-2.6.17-rc6.mod/arch/x86_64/kernel/traps.c 2006-06-06 22:51:01.000000000 +0900 @@ -445,7 +445,7 @@ void __kprobes __die(const char * str, s printk_address(regs->rip); printk(" RSP <%016lx>\n", regs->rsp); if (kexec_should_crash(current)) - crash_kexec(regs); + crash_kexec(CRASH_ON_DIE, regs, NULL); } void die(const char * str, struct pt_regs * regs, long err) @@ -469,7 +469,7 @@ void __kprobes die_nmi(char *str, struct printk(str, safe_smp_processor_id()); show_registers(regs); if (kexec_should_crash(current)) - crash_kexec(regs); + crash_kexec(CRASH_ON_DIE, regs, NULL); if (panic_on_timeout || panic_on_oops) panic("nmi watchdog"); printk("console shuts up ...\n"); diff -Nurp linux-2.6.17-rc6/drivers/char/sysrq.c linux-2.6.17-rc6.mod/drivers/char/sysrq.c --- linux-2.6.17-rc6/drivers/char/sysrq.c 2006-06-06 22:47:40.000000000 +0900 +++ linux-2.6.17-rc6.mod/drivers/char/sysrq.c 2006-06-06 22:51:01.000000000 +0900 @@ -99,7 +99,7 @@ static struct sysrq_key_op sysrq_unraw_o static void sysrq_handle_crashdump(int key, struct pt_regs *pt_regs, struct tty_struct *tty) { - crash_kexec(pt_regs); + crash_kexec(CRASH_ON_SYSRQ, pt_regs, NULL); } static struct sysrq_key_op sysrq_crashdump_op = { .handler = sysrq_handle_crashdump, diff -Nurp linux-2.6.17-rc6/include/linux/kexec.h linux-2.6.17-rc6.mod/include/linux/kexec.h --- linux-2.6.17-rc6/include/linux/kexec.h 2006-03-20 14:53:29.000000000 +0900 +++ linux-2.6.17-rc6.mod/include/linux/kexec.h 2006-06-06 22:51:01.000000000 +0900 @@ -1,12 +1,18 @@ #ifndef LINUX_KEXEC_H #define LINUX_KEXEC_H +/* crash type for notifier */ +#define CRASH_ON_PANIC 1 +#define CRASH_ON_DIE 2 +#define CRASH_ON_SYSRQ 3 + #ifdef CONFIG_KEXEC #include <linux/types.h> #include <linux/list.h> #include <linux/linkage.h> #include <linux/compat.h> #include <linux/ioport.h> +#include <linux/notifier.h> #include <asm/kexec.h> /* Verify architecture specific macros are defined */ @@ -103,9 +109,11 @@ extern asmlinkage long compat_sys_kexec_ #endif extern struct page *kimage_alloc_control_pages(struct kimage *image, unsigned int order); -extern void crash_kexec(struct pt_regs *); +extern void crash_kexec(int, struct pt_regs *, void *); int kexec_should_crash(struct task_struct *); extern struct kimage *kexec_image; +extern struct raw_notifier_head crash_notifier_list; +extern int kdump_safe; #define KEXEC_ON_CRASH 0x00000001 #define KEXEC_ARCH_MASK 0xffff0000 @@ -133,7 +141,7 @@ extern note_buf_t *crash_notes; #else /* !CONFIG_KEXEC */ struct pt_regs; struct task_struct; -static inline void crash_kexec(struct pt_regs *regs) { } +static inline void crash_kexec(int type, struct pt_regs *regs, void *v) { } static inline int kexec_should_crash(struct task_struct *p) { return 0; } #endif /* CONFIG_KEXEC */ #endif /* LINUX_KEXEC_H */ diff -Nurp linux-2.6.17-rc6/include/linux/sysctl.h linux-2.6.17-rc6.mod/include/linux/sysctl.h --- linux-2.6.17-rc6/include/linux/sysctl.h 2006-06-06 22:47:54.000000000 +0900 +++ linux-2.6.17-rc6.mod/include/linux/sysctl.h 2006-06-06 22:51:01.000000000 +0900 @@ -148,6 +148,7 @@ enum KERN_SPIN_RETRY=70, /* int: number of spinlock retries */ KERN_ACPI_VIDEO_FLAGS=71, /* int: flags for setting up video after ACPI sleep */ KERN_IA64_UNALIGNED=72, /* int: ia64 unaligned userland trap enable */ + KERN_KDUMP_SAFE=73, /* int: crash notifier flag */ }; diff -Nurp linux-2.6.17-rc6/kernel/kexec.c linux-2.6.17-rc6.mod/kernel/kexec.c --- linux-2.6.17-rc6/kernel/kexec.c 2006-03-20 14:53:29.000000000 +0900 +++ linux-2.6.17-rc6.mod/kernel/kexec.c 2006-06-06 22:51:17.000000000 +0900 @@ -20,6 +20,8 @@ #include <linux/syscalls.h> #include <linux/ioport.h> #include <linux/hardirq.h> +#include <linux/module.h> +#include <linux/notifier.h> #include <asm/page.h> #include <asm/uaccess.h> @@ -27,6 +29,11 @@ #include <asm/system.h> #include <asm/semaphore.h> + +RAW_NOTIFIER_HEAD(crash_notifier_list); +EXPORT_SYMBOL(crash_notifier_list); +int kdump_safe = 1; + /* Per cpu memory for storing cpu states in case of system crash. */ note_buf_t* crash_notes; @@ -1040,7 +1047,15 @@ asmlinkage long compat_sys_kexec_load(un } #endif -void crash_kexec(struct pt_regs *regs) +static inline void notify_crash(int type, void *v) +{ +#ifdef CONFIG_SYSCTL + if (!kdump_safe) + raw_notifier_call_chain(&crash_notifier_list, type, v); +#endif +} + +void crash_kexec(int type, struct pt_regs *regs, void *v) { struct kimage *image; int locked; @@ -1061,6 +1076,7 @@ void crash_kexec(struct pt_regs *regs) struct pt_regs fixed_regs; crash_setup_regs(&fixed_regs, regs); machine_crash_shutdown(&fixed_regs); + notify_crash(type, v); machine_kexec(image); } xchg(&kexec_lock, 0); diff -Nurp linux-2.6.17-rc6/kernel/panic.c linux-2.6.17-rc6.mod/kernel/panic.c --- linux-2.6.17-rc6/kernel/panic.c 2006-06-06 22:47:54.000000000 +0900 +++ linux-2.6.17-rc6.mod/kernel/panic.c 2006-06-06 22:51:01.000000000 +0900 @@ -85,7 +85,7 @@ NORET_TYPE void panic(const char * fmt, * everything else. * Do we want to call this before we try to display a message? */ - crash_kexec(NULL); + crash_kexec(CRASH_ON_PANIC, NULL, buf); #ifdef CONFIG_SMP /* diff -Nurp linux-2.6.17-rc6/kernel/sysctl.c linux-2.6.17-rc6.mod/kernel/sysctl.c --- linux-2.6.17-rc6/kernel/sysctl.c 2006-06-06 22:47:54.000000000 +0900 +++ linux-2.6.17-rc6.mod/kernel/sysctl.c 2006-06-06 22:51:01.000000000 +0900 @@ -46,6 +46,7 @@ #include <linux/syscalls.h> #include <linux/nfs_fs.h> #include <linux/acpi.h> +#include <linux/kexec.h> #include <asm/uaccess.h> #include <asm/processor.h> @@ -683,6 +684,16 @@ static ctl_table kern_table[] = { .proc_handler = &proc_dointvec, }, #endif +#if defined(CONFIG_KEXEC) + { + .ctl_name = KERN_KDUMP_SAFE, + .procname = "kdump_safe", + .data = &kdump_safe, + .maxlen = sizeof (int), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, +#endif { .ctl_name = 0 } }; 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