Commit 024e4ec1 authored by Linus Torvalds's avatar Linus Torvalds

Merge tag 'please-pull-pstore' of git://

Pull pstore patches from Tony Luck:
 "A few fixes to reduce places where pstore might hang a system in the
  crash path.  Plus a new mountpoint (/sys/fs/pstore ...  makes more
  sense then /dev/pstore)."

Fix up trivial conflict in drivers/firmware/efivars.c

* tag 'please-pull-pstore' of git://
  pstore: Create a convenient mount point for pstore
  efi_pstore: Introducing workqueue updating sysfs
  efivars: Disable external interrupt while holding efivars->lock
  efi_pstore: Avoid deadlock in non-blocking paths
  pstore: Avoid deadlock in panic and emergency-restart path
parents 850cb82b fb0af3f2
Where: /dev/pstore/...
Where: /sys/fs/pstore/... (or /dev/pstore/...)
Date: March 2011
Kernel Version: 2.6.39
......@@ -11,9 +11,9 @@ Description: Generic interface to platform dependent persistent storage.
of the console log is captured, but other interesting
data can also be saved.
# mount -t pstore -o kmsg_bytes=8000 - /dev/pstore
# mount -t pstore -o kmsg_bytes=8000 - /sys/fs/pstore
$ ls -l /dev/pstore
$ ls -l /sys/fs/pstore/
total 0
-r--r--r-- 1 root root 7896 Nov 30 15:38 dmesg-erst-1
......@@ -27,9 +27,9 @@ Description: Generic interface to platform dependent persistent storage.
the file will signal to the underlying persistent storage
device that it can reclaim the space for later re-use.
$ rm /dev/pstore/dmesg-erst-1
$ rm /sys/fs/pstore/dmesg-erst-1
The expectation is that all files in /dev/pstore
The expectation is that all files in /sys/fs/pstore/
will be saved elsewhere and erased from persistent store
soon after boot to free up space ready for the next
This diff is collapsed.
......@@ -418,9 +418,25 @@ static struct file_system_type pstore_fs_type = {
.kill_sb = pstore_kill_sb,
static struct kobject *pstore_kobj;
static int __init init_pstore_fs(void)
return register_filesystem(&pstore_fs_type);
int err = 0;
/* Create a convenient mount point for people to access pstore */
pstore_kobj = kobject_create_and_add("pstore", fs_kobj);
if (!pstore_kobj) {
err = -ENOMEM;
goto out;
err = register_filesystem(&pstore_fs_type);
if (err < 0)
return err;
......@@ -96,6 +96,27 @@ static const char *get_reason_str(enum kmsg_dump_reason reason)
bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
* In case of NMI path, pstore shouldn't be blocked
* regardless of reason.
if (in_nmi())
return true;
switch (reason) {
/* In panic case, other cpus are stopped by smp_send_stop(). */
/* Emergency restart shouldn't be blocked by spin lock. */
return true;
return false;
* callback from kmsg_dump. (s2,l2) has the most recently
* written bytes, older bytes are in (s1,l1). Save as much
......@@ -114,10 +135,12 @@ static void pstore_dump(struct kmsg_dumper *dumper,
why = get_reason_str(reason);
if (in_nmi()) {
is_locked = spin_trylock(&psinfo->buf_lock);
if (!is_locked)
pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
if (pstore_cannot_block_path(reason)) {
is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
if (!is_locked) {
pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
, in_nmi() ? "NMI" : why);
} else
spin_lock_irqsave(&psinfo->buf_lock, flags);
......@@ -143,9 +166,9 @@ static void pstore_dump(struct kmsg_dumper *dumper,
total += hsize + len;
if (in_nmi()) {
if (pstore_cannot_block_path(reason)) {
if (is_locked)
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
} else
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
......@@ -740,7 +740,8 @@ struct efivars {
* 1) ->list - adds, removals, reads, writes
* 2) ops.[gs]et_variable() calls.
* It must not be held when creating sysfs entries or calling kmalloc.
* ops.get_next_variable() is only called from register_efivars(),
* ops.get_next_variable() is only called from register_efivars()
* or efivar_update_sysfs_entries(),
* which is protected by the BKL, so that path is safe.
spinlock_t lock;
......@@ -68,12 +68,18 @@ struct pstore_info {
extern int pstore_register(struct pstore_info *);
extern bool pstore_cannot_block_path(enum kmsg_dump_reason reason);
static inline int
pstore_register(struct pstore_info *psi)
return -ENODEV;
static inline bool
pstore_cannot_block_path(enum kmsg_dump_reason reason)
return false;
#endif /*_LINUX_PSTORE_H*/
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