Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758876AbZJPMKO (ORCPT ); Fri, 16 Oct 2009 08:10:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754255AbZJPMKK (ORCPT ); Fri, 16 Oct 2009 08:10:10 -0400 Received: from ernst.netinsight.se ([194.16.221.21]:54848 "HELO ernst.netinsight.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751063AbZJPMKH (ORCPT ); Fri, 16 Oct 2009 08:10:07 -0400 Date: Fri, 16 Oct 2009 14:09:18 +0200 From: Simon Kagstrom To: Ingo Molnar , linux-mtd Cc: dedekind1@gmail.com, Linus Torvalds , David Woodhouse , Andrew Morton , LKML , "Koskinen Aaro (Nokia-D/Helsinki)" , Alan Cox Subject: [PATCH v11 4/5] core: Add kernel message dumper to call on oopses and panics Message-ID: <20091016140918.3981cfa2@marrow.netinsight.se> In-Reply-To: <20091016101045.GA3263@elte.hu> References: <20091015094057.7298e0d7@marrow.netinsight.se> <20091015094805.754461fa@marrow.netinsight.se> <20091015093133.GF10546@elte.hu> <20091015161052.0752208e@marrow.netinsight.se> <20091015154640.GA11408@elte.hu> <20091016094601.4e2c2d3e@marrow.netinsight.se> <20091016080935.GA3895@elte.hu> <1255681467.32489.360.camel@localhost> <20091016112556.6902b2dc@marrow.netinsight.se> <20091016101045.GA3263@elte.hu> X-Mailer: Claws Mail 3.7.3 (GTK+ 2.16.1; i486-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6558 Lines: 238 The core functionality is implemented as per Linus suggestion from http://lists.infradead.org/pipermail/linux-mtd/2009-October/027620.html (with the kmsg_dump implementation by Linus). A struct kmsg_dumper has been added which contains a callback to dump the kernel log buffers on crashes. The kmsg_dump function gets called from oops_exit() and panic() and invokes this callbacks with the crash reason. Signed-off-by: Simon Kagstrom Reviewed-by: Anders Grafstrom Reviewed-by: Ingo Molnar --- The bikeshed paint is drying: ChangeLog: * (Ingo Molnar): Flatten lock use * (Artem, Aaro): Fix style issues include/linux/kmsg_dump.h | 44 ++++++++++++++++++ kernel/panic.c | 3 + kernel/printk.c | 112 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 159 insertions(+), 0 deletions(-) create mode 100644 include/linux/kmsg_dump.h diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h new file mode 100644 index 0000000..7f089ec --- /dev/null +++ b/include/linux/kmsg_dump.h @@ -0,0 +1,44 @@ +/* + * linux/include/kmsg_dump.h + * + * Copyright (C) 2009 Net Insight AB + * + * Author: Simon Kagstrom + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive + * for more details. + */ +#ifndef _LINUX_KMSG_DUMP_H +#define _LINUX_KMSG_DUMP_H + +#include + +enum kmsg_dump_reason { + KMSG_DUMP_OOPS, + KMSG_DUMP_PANIC, +}; + +/** + * struct kmsg_dumper - kernel crash message dumper structure + * @dump: The callback which gets called on crashes. The buffer is passed + * as two sections, where s1 (length l1) contains the older + * messages and s2 (length l2) contains the newer. + * @list: Entry in the dumper list (private) + * @registered: Flag that specifies if this is already registered + */ +struct kmsg_dumper { + void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason, + const char *s1, unsigned long l1, + const char *s2, unsigned long l2); + struct list_head list; + int registered; +}; + +void kmsg_dump(enum kmsg_dump_reason reason); + +int kmsg_dump_register(struct kmsg_dumper *dumper); + +int kmsg_dump_unregister(struct kmsg_dumper *dumper); + +#endif /* _LINUX_KMSG_DUMP_H */ diff --git a/kernel/panic.c b/kernel/panic.c index c0b33b8..763296d 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -10,6 +10,7 @@ */ #include #include +#include #include #include #include @@ -76,6 +77,7 @@ NORET_TYPE void panic(const char * fmt, ...) dump_stack(); #endif + kmsg_dump(KMSG_DUMP_PANIC); /* * If we have crashed and we have a crash kernel loaded let it handle * everything else. @@ -341,6 +343,7 @@ void oops_exit(void) { do_oops_enter_exit(); print_oops_end_marker(); + kmsg_dump(KMSG_DUMP_OOPS); } #ifdef WANT_WARN_ON_SLOWPATH diff --git a/kernel/printk.c b/kernel/printk.c index f38b07f..f711b99 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -33,6 +33,7 @@ #include #include #include +#include #include @@ -1405,3 +1406,114 @@ bool printk_timed_ratelimit(unsigned long *caller_jiffies, } EXPORT_SYMBOL(printk_timed_ratelimit); #endif + +static DEFINE_SPINLOCK(dump_list_lock); +static LIST_HEAD(dump_list); + +/** + * kmsg_dump_register - register a kernel log dumper. + * @dump: pointer to the kmsg_dumper structure + * + * Adds a kernel log dumper to the system. The dump callback in the + * structure will be called when the kernel oopses or panics and must be + * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. + */ +int kmsg_dump_register(struct kmsg_dumper *dumper) +{ + unsigned long flags; + int err = -EBUSY; + + /* The dump callback needs to be set */ + if (!dumper->dump) + return -EINVAL; + + spin_lock_irqsave(&dump_list_lock, flags); + /* Don't allow registering multiple times */ + if (!dumper->registered) { + dumper->registered = 1; + list_add_tail(&dumper->list, &dump_list); + err = 0; + } + spin_unlock_irqrestore(&dump_list_lock, flags); + + return err; +} +EXPORT_SYMBOL_GPL(kmsg_dump_register); + +/** + * kmsg_dump_unregister - unregister a kmsg dumper. + * @dump: pointer to the kmsg_dumper structure + * + * Removes a dump device from the system. Returns zero on success and + * %-EINVAL otherwise. + */ +int kmsg_dump_unregister(struct kmsg_dumper *dumper) +{ + unsigned long flags; + int err = -EINVAL; + + spin_lock_irqsave(&dump_list_lock, flags); + if (dumper->registered) { + dumper->registered = 0; + list_del(&dumper->list); + err = 0; + } + spin_unlock_irqrestore(&dump_list_lock, flags); + + return err; +} +EXPORT_SYMBOL_GPL(kmsg_dump_unregister); + +static const char const *kmsg_reasons[] = { + [KMSG_DUMP_OOPS] = "oops", + [KMSG_DUMP_PANIC] = "panic", +}; + +static const char *kmsg_to_str(enum kmsg_dump_reason reason) +{ + if (reason >= ARRAY_SIZE(kmsg_reasons) || reason < 0) + return "unknown"; + + return kmsg_reasons[reason]; +} + +/** + * kmsg_dump - dump kernel log to kernel message dumpers. + * @reason: the reason (oops, panic etc) for dumping + * + * Iterate through each of the dump devices and call the oops/panic + * callbacks with the log buffer. + */ +void kmsg_dump(enum kmsg_dump_reason reason) +{ + unsigned long len = ACCESS_ONCE(log_end); + struct kmsg_dumper *dumper; + const char *s1, *s2; + unsigned long l1, l2; + unsigned long flags; + + s1 = ""; + l1 = 0; + s2 = log_buf; + l2 = len; + + /* Have we rotated around the circular buffer? */ + if (len > log_buf_len) { + unsigned long pos = len & LOG_BUF_MASK; + + s1 = log_buf + pos; + l1 = log_buf_len - pos; + + s2 = log_buf; + l2 = pos; + } + + if (!spin_trylock_irqsave(&dump_list_lock, flags)) { + printk(KERN_ERR "dump_kmsg: dump list lock is held during %s, skipping dump\n", + kmsg_to_str(reason)); + return; + } + list_for_each_entry(dumper, &dump_list, list) + dumper->dump(dumper, reason, s1, l1, s2, l2); + spin_unlock_irqrestore(&dump_list_lock, flags); +} -- 1.6.0.4 -- 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/