From ae87221d3ce49d9de1e43756da834fd0bf05a2ad Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Fri, 24 Aug 2007 16:11:54 -0700 Subject: 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 Cc: Mathieu Desnoyers Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- include/linux/sysfs.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux/sysfs.h') 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_ */ -- cgit v1.2.3 From f1282c844e86db5a041afa41335b5f9eea6cec0c Mon Sep 17 00:00:00 2001 From: Neil Brown Date: Wed, 16 Jul 2008 08:58:04 +1000 Subject: sysfs: Support sysfs_notify from atomic context with new sysfs_notify_dirent Support sysfs_notify from atomic context with new sysfs_notify_dirent sysfs_notify currently takes sysfs_mutex. This means that it cannot be called in atomic context. sysfs_mutex is sometimes held over a malloc (sysfs_rename_dir) so it can block on low memory. In md I want to be able to notify on a sysfs attribute from atomic context, and I don't want to block on low memory because I could be in the writeout path for freeing memory. So: - export the "sysfs_dirent" structure along with sysfs_get, sysfs_put and sysfs_get_dirent so I can get the sysfs_dirent that I want to notify on and hold it in an md structure. - split sysfs_notify_dirent out of sysfs_notify so the sysfs_dirent can be notified on with no blocking (just a spinlock). Signed-off-by: Neil Brown Acked-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- include/linux/sysfs.h | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) (limited to 'include/linux/sysfs.h') diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 8ec406afb3eb..d8e0230f1e68 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -78,6 +78,8 @@ struct sysfs_ops { ssize_t (*store)(struct kobject *,struct attribute *,const char *, size_t); }; +struct sysfs_dirent; + #ifdef CONFIG_SYSFS int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), @@ -118,10 +120,13 @@ void sysfs_remove_file_from_group(struct kobject *kobj, const struct attribute *attr, const char *group); void sysfs_notify(struct kobject *kobj, char *dir, char *attr); - +void sysfs_notify_dirent(struct sysfs_dirent *sd); +struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, + const unsigned char *name); +struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd); +void sysfs_put(struct sysfs_dirent *sd); void sysfs_printk_last_file(void); - -extern int __must_check sysfs_init(void); +int __must_check sysfs_init(void); #else /* CONFIG_SYSFS */ @@ -227,6 +232,22 @@ static inline void sysfs_remove_file_from_group(struct kobject *kobj, static inline void sysfs_notify(struct kobject *kobj, char *dir, char *attr) { } +static inline void sysfs_notify_dirent(struct sysfs_dirent *sd) +{ +} +static inline +struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, + const unsigned char *name) +{ + return NULL; +} +static inline struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd) +{ + return NULL; +} +static inline void sysfs_put(struct sysfs_dirent *sd) +{ +} static inline int __must_check sysfs_init(void) { -- cgit v1.2.3 From 8c0e3998f5b71e68fe6b6e489a92e052715e563c Mon Sep 17 00:00:00 2001 From: Trent Piepho Date: Thu, 25 Sep 2008 16:45:13 -0700 Subject: sysfs: Make dir and name args to sysfs_notify() const Because they can be, and because code like this produces a warning if they're not: struct device_attribute dev_attr; sysfs_notify(&kobj, NULL, dev_attr.attr.name); Signed-off-by: Trent Piepho CC: Neil Brown Signed-off-by: Greg Kroah-Hartman --- include/linux/sysfs.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux/sysfs.h') diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index d8e0230f1e68..b330e289d71f 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -119,7 +119,7 @@ int sysfs_add_file_to_group(struct kobject *kobj, void sysfs_remove_file_from_group(struct kobject *kobj, const struct attribute *attr, const char *group); -void sysfs_notify(struct kobject *kobj, char *dir, char *attr); +void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr); void sysfs_notify_dirent(struct sysfs_dirent *sd); struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd, const unsigned char *name); @@ -229,7 +229,8 @@ static inline void sysfs_remove_file_from_group(struct kobject *kobj, { } -static inline void sysfs_notify(struct kobject *kobj, char *dir, char *attr) +static inline void sysfs_notify(struct kobject *kobj, const char *dir, + const char *attr) { } static inline void sysfs_notify_dirent(struct sysfs_dirent *sd) -- cgit v1.2.3 From 030c1d2bfcc2187650fb975456ca0b61a5bb77f4 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Thu, 8 May 2008 14:41:00 -0700 Subject: kobject: Fix kobject_rename and !CONFIG_SYSFS When looking at kobject_rename I found two bugs with that exist when sysfs support is disabled in the kernel. kobject_rename does not change the name on the kobject when sysfs support is not compiled in. kobject_rename without locking attempts to check the validity of a rename operation, which the kobject layer simply does not have the infrastructure to do. This patch documents the previously unstated requirement of kobject_rename that is the responsibility of the caller to provide mutual exclusion and to be certain that the new_name for the kobject is valid. This patch modifies sysfs_rename_dir in !CONFIG_SYSFS case to call kobject_set_name to actually change the kobject_name. This patch removes the bogus and misleading check in kobject_rename that attempts to see if a rename is valid. The check is bogus because we do not have the proper locking. The check is misleading because it looks like we can and do perform checking at the kobject level that we don't. Signed-off-by: Eric W. Biederman Signed-off-by: Greg Kroah-Hartman --- include/linux/sysfs.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include/linux/sysfs.h') diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index b330e289d71f..39924a962207 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -20,6 +20,8 @@ struct kobject; struct module; +extern int kobject_set_name(struct kobject *kobj, const char *name, ...) + __attribute__((format(printf, 2, 3))); /* FIXME * The *owner field is no longer used, but leave around * until the tree gets cleaned up fully. @@ -147,7 +149,7 @@ static inline void sysfs_remove_dir(struct kobject *kobj) static inline int sysfs_rename_dir(struct kobject *kobj, const char *new_name) { - return 0; + return kobject_set_name(kobj, "%s", new_name); } static inline int sysfs_move_dir(struct kobject *kobj, -- cgit v1.2.3 From 0b4a4fea253e1296222603ccc55430ed7cd9413a Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Thu, 3 Jul 2008 18:05:28 -0700 Subject: kobject: Cleanup kobject_rename and !CONFIG_SYSFS It finally dawned on me what the clean fix to sysfs_rename_dir calling kobject_set_name is. Move the work into kobject_rename where it belongs. The callers serialize us anyway so this is safe. Signed-off-by: Eric W. Biederman Acked-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- include/linux/sysfs.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'include/linux/sysfs.h') diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 39924a962207..b330e289d71f 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -20,8 +20,6 @@ struct kobject; struct module; -extern int kobject_set_name(struct kobject *kobj, const char *name, ...) - __attribute__((format(printf, 2, 3))); /* FIXME * The *owner field is no longer used, but leave around * until the tree gets cleaned up fully. @@ -149,7 +147,7 @@ static inline void sysfs_remove_dir(struct kobject *kobj) static inline int sysfs_rename_dir(struct kobject *kobj, const char *new_name) { - return kobject_set_name(kobj, "%s", new_name); + return 0; } static inline int sysfs_move_dir(struct kobject *kobj, -- cgit v1.2.3