From 86b1ae38c0a62409dc862a28e3f08920f55f944b Mon Sep 17 00:00:00 2001 From: Hariprasad Nellitheertha Date: Sat, 25 Jun 2005 14:58:25 -0700 Subject: [PATCH] kdump: sysrq trigger mechanism for kexec based crashdumps Add a sysrq-trigger mechanism for kexec based crashdumps. Alt-Sysrq-c triggers a kexec based crashdump. Signed-off-by: Hariprasad Nellitheertha Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/sysrq.txt | 5 +++++ drivers/char/sysrq.c | 24 ++++++++++++++++++++++-- 2 files changed, 27 insertions(+), 2 deletions(-) diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt index f98c2e31c143..136d817c01ba 100644 --- a/Documentation/sysrq.txt +++ b/Documentation/sysrq.txt @@ -72,6 +72,8 @@ On all - write a character to /proc/sysrq-trigger. eg: 'b' - Will immediately reboot the system without syncing or unmounting your disks. +'c' - Will perform a kexec reboot in order to take a crashdump. + 'o' - Will shut your system off (if configured and supported). 's' - Will attempt to sync all mounted filesystems. @@ -122,6 +124,9 @@ useful when you want to exit a program that will not let you switch consoles. re'B'oot is good when you're unable to shut down. But you should also 'S'ync and 'U'mount first. +'C'rashdump can be used to manually trigger a crashdump when the system is hung. +The kernel needs to have been built with CONFIG_KEXEC enabled. + 'S'ync is great when your system is locked up, it allows you to sync your disks and will certainly lessen the chance of data loss and fscking. Note that the sync hasn't taken place until you see the "OK" and "Done" appear diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c index f59f7cbd525b..53b2c8fab00e 100644 --- a/drivers/char/sysrq.c +++ b/drivers/char/sysrq.c @@ -35,6 +35,7 @@ #include #include #include +#include #include @@ -94,6 +95,21 @@ static struct sysrq_key_op sysrq_unraw_op = { }; #endif /* CONFIG_VT */ +#ifdef CONFIG_KEXEC +/* crashdump sysrq handler */ +static void sysrq_handle_crashdump(int key, struct pt_regs *pt_regs, + struct tty_struct *tty) +{ + crash_kexec(); +} +static struct sysrq_key_op sysrq_crashdump_op = { + .handler = sysrq_handle_crashdump, + .help_msg = "Crashdump", + .action_msg = "Trigger a crashdump", + .enable_mask = SYSRQ_ENABLE_DUMP, +}; +#endif + /* reboot sysrq handler */ static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs, struct tty_struct *tty) @@ -273,8 +289,12 @@ static struct sysrq_key_op *sysrq_key_table[SYSRQ_KEY_TABLE_LENGTH] = { it is handled specially on the sparc and will never arrive */ /* b */ &sysrq_reboot_op, -/* c */ NULL, -/* d */ NULL, +#ifdef CONFIG_KEXEC +/* c */ &sysrq_crashdump_op, +#else +/* c */ NULL, +#endif +/* d */ NULL, /* e */ &sysrq_term_op, /* f */ &sysrq_moom_op, /* g */ NULL, -- cgit v1.2.3