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| author | Andrew Morton <akpm@linux-foundation.org> | 2007-08-24 16:11:54 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-10-16 09:24:41 -0700 |
| commit | ae87221d3ce49d9de1e43756da834fd0bf05a2ad (patch) | |
| tree | f96792656b00e95c307f3f37369c98a85ce38207 | |
| parent | e94320939f44e0cbaccc3f259a5778abced4949c (diff) | |
| download | linux-ae87221d3ce49d9de1e43756da834fd0bf05a2ad.tar.bz2 | |
sysfs: crash debugging
Print the name of the last-accessed sysfs file when we oops, to help track
down oopses which occur in sysfs store/read handlers. Because these oopses
tend to not leave any trace of the offending code in the stack traces.
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | arch/x86/kernel/dumpstack_32.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/dumpstack_64.c | 2 | ||||
| -rw-r--r-- | fs/sysfs/file.c | 13 | ||||
| -rw-r--r-- | include/linux/sysfs.h | 6 |
4 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c index 201ee359a1a9..1a78180f08d3 100644 --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -13,6 +13,7 @@ #include <linux/kexec.h> #include <linux/bug.h> #include <linux/nmi.h> +#include <linux/sysfs.h> #include <asm/stacktrace.h> @@ -343,6 +344,7 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err) printk("DEBUG_PAGEALLOC"); #endif printk("\n"); + sysfs_printk_last_file(); if (notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV) == NOTIFY_STOP) return 1; diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 086cc8118e39..96a5db7da8a7 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -13,6 +13,7 @@ #include <linux/kexec.h> #include <linux/bug.h> #include <linux/nmi.h> +#include <linux/sysfs.h> #include <asm/stacktrace.h> @@ -489,6 +490,7 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err) printk("DEBUG_PAGEALLOC"); #endif printk("\n"); + sysfs_printk_last_file(); if (notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV) == NOTIFY_STOP) return 1; diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index c9e4e5091da1..ce8339c70a4b 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -19,10 +19,18 @@ #include <linux/poll.h> #include <linux/list.h> #include <linux/mutex.h> +#include <linux/limits.h> #include <asm/uaccess.h> #include "sysfs.h" +/* used in crash dumps to help with debugging */ +static char last_sysfs_file[PATH_MAX]; +void sysfs_printk_last_file(void) +{ + printk(KERN_EMERG "last sysfs file: %s\n", last_sysfs_file); +} + /* * There's one sysfs_buffer for each open file and one * sysfs_open_dirent for each sysfs_dirent with one or more open @@ -328,6 +336,11 @@ static int sysfs_open_file(struct inode *inode, struct file *file) struct sysfs_buffer *buffer; struct sysfs_ops *ops; int error = -EACCES; + char *p; + + p = d_path(&file->f_path, last_sysfs_file, sizeof(last_sysfs_file)); + if (p) + memmove(last_sysfs_file, p, strlen(p) + 1); /* need attr_sd for attr and ops, its parent for kobj */ if (!sysfs_get_active_two(attr_sd)) diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 37fa24152bd8..8ec406afb3eb 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -119,6 +119,8 @@ void sysfs_remove_file_from_group(struct kobject *kobj, void sysfs_notify(struct kobject *kobj, char *dir, char *attr); +void sysfs_printk_last_file(void); + extern int __must_check sysfs_init(void); #else /* CONFIG_SYSFS */ @@ -231,6 +233,10 @@ static inline int __must_check sysfs_init(void) return 0; } +static inline void sysfs_printk_last_file(void) +{ +} + #endif /* CONFIG_SYSFS */ #endif /* _SYSFS_H_ */ |