From patchwork Wed Oct 14 13:41:18 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Simon Kagstrom X-Patchwork-Id: 35967 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from bombadil.infradead.org (bombadil.infradead.org [18.85.46.34]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 50F29B7B78 for ; Thu, 15 Oct 2009 00:44:26 +1100 (EST) Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.69 #1 (Red Hat Linux)) id 1My46c-0006r0-O2; Wed, 14 Oct 2009 13:41:30 +0000 Received: from ernst.netinsight.se ([194.16.221.21]) by bombadil.infradead.org with smtp (Exim 4.69 #1 (Red Hat Linux)) id 1My46Z-0006mI-Ih for linux-mtd@lists.infradead.org; Wed, 14 Oct 2009 13:41:29 +0000 Received: from marrow.netinsight.se (unverified [10.100.3.78]) by ernst.netinsight.se (EMWAC SMTPRS 0.83) with SMTP id ; Wed, 14 Oct 2009 15:41:16 +0200 Date: Wed, 14 Oct 2009 15:41:18 +0200 From: Simon Kagstrom Subject: [PATCH v6 4/5]: core: Add kernel message dumper to call on oopses and panics Message-ID: <20091014154118.5c8cc998@marrow.netinsight.se> In-Reply-To: <20091014153458.05e31db6@marrow.netinsight.se> References: <20091012113758.GB11035@elte.hu> <20091012140149.6789efab@marrow.netinsight.se> <20091012120951.GA16799@elte.hu> <1255349748.10605.13.camel@macbook.infradead.org> <20091012122023.GA19365@elte.hu> <20091012150650.51a4b4dc@marrow.netinsight.se> <20091012131528.GC25464@elte.hu> <20091012153937.0dcd73e5@marrow.netinsight.se> <20091012110954.67d7d8d8.akpm@linux-foundation.org> <20091012182346.GH17138@elte.hu> <20091014153458.05e31db6@marrow.netinsight.se> X-Mailer: Claws Mail 3.7.3 (GTK+ 2.16.1; i486-pc-linux-gnu) Mime-Version: 1.0 X-CRM114-Version: 20090807-BlameThorstenAndJenny ( TRE 0.7.6 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20091014_094127_759503_4D772EF1 X-CRM114-Status: GOOD ( 22.58 ) X-Spam-Score: 1.6 (+) X-Spam-Report: SpamAssassin version 3.2.5 on bombadil.infradead.org summary: Content analysis details: (1.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- 1.6 MISSING_HEADERS Missing To: header Cc: Artem Bityutskiy , Linus Torvalds , LKML , "Koskinen Aaro \(Nokia-D/Helsinki\)" , linux-mtd , Ingo Molnar , David Woodhouse , Andrew Morton , Alan Cox X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-mtd-bounces@lists.infradead.org Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org The core functionality is implemented as per Linus suggestion from http://lists.infradead.org/pipermail/linux-mtd/2009-October/027620.html (with the dump_kmsg implementation by Linus). A struct kmsg_dumper has been added which contains a callback to dump the kernel log buffers on crashes. The dump_kmsg 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 --- ChangeLog: Review comments from Linus Torvalds and Anders Grafström: * Rename structures and file names * Remove setup callback and unify panic/oops callbacks and instead add a reason parameter * Use a regular spinlock and try it when dumping (fail if held) * Check if the dumper is already registered * Various style fixes/cleanup include/linux/kmsg_dump.h | 37 ++++++++++++++++ kernel/panic.c | 3 + kernel/printk.c | 105 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 145 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..a0d6b55 --- /dev/null +++ b/include/linux/kmsg_dump.h @@ -0,0 +1,37 @@ +/* + * 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 { + void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason, + const char *s1, unsigned long l1, + const char *s2, unsigned long l2); + void *priv; + struct list_head list; + int registered; +}; + +void dump_kmsg(enum kmsg_dump_reason reason); + +int register_kmsg_dumper(struct kmsg_dumper *dumper, void *priv); + +void unregister_kmsg_dumper(struct kmsg_dumper *dumper); + +#endif /* _LINUX_DUMP_DEVICE_H */ diff --git a/kernel/panic.c b/kernel/panic.c index c0b33b8..3a5a93f 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 + dump_kmsg(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(); + dump_kmsg(kmsg_dump_oops); } #ifdef WANT_WARN_ON_SLOWPATH diff --git a/kernel/printk.c b/kernel/printk.c index f38b07f..a97abb0 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -33,6 +33,8 @@ #include #include #include +#include +#include #include @@ -1405,3 +1407,106 @@ bool printk_timed_ratelimit(unsigned long *caller_jiffies, } EXPORT_SYMBOL(printk_timed_ratelimit); #endif + +static LIST_HEAD(dump_list); +static DEFINE_SPINLOCK(dump_list_lock); + +/** + * register_dump_device - register a kernel log dumper. + * @dump: pointer to the dump structure + * @priv: private data for the 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 register_kmsg_dumper(struct kmsg_dumper *dumper, void *priv) +{ + unsigned long flags; + + /* The dump callback needs to be set */ + if (!dumper->dump) + return -EINVAL; + + /* Don't allow registering multiple times */ + if (dumper->registered) + return -EBUSY; + + dumper->priv = priv; + dumper->registered = 1; + + spin_lock_irqsave(&dump_list_lock, flags); + list_add(&dumper->list, &dump_list); + spin_unlock_irqrestore(&dump_list_lock, flags); + return 0; +} +EXPORT_SYMBOL(register_kmsg_dumper); + +/** + * unregister_dump_device - unregister a dumpdevice. + * @dump: pointer to the dump structure + * + * Removes a dump device from the system. + */ +void unregister_kmsg_dumper(struct kmsg_dumper *dumper) +{ + unsigned long flags; + + spin_lock_irqsave(&dump_list_lock, flags); + list_del(&dumper->list); + spin_unlock_irqrestore(&dump_list_lock, flags); +} +EXPORT_SYMBOL(unregister_kmsg_dumper); + +static const char *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]; +} + +/** + * dump_kmsg - 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 dump_kmsg(enum kmsg_dump_reason reason) +{ + unsigned long len = ACCESS_ONCE(log_end); + struct kmsg_dumper *dumper; + const char *s1, *s2; + unsigned long l1, l2; + + 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(&dump_list_lock)) { + 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(&dump_list_lock); +}