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authorLinus Torvalds <torvalds@linux-foundation.org>2013-02-21 09:38:18 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-21 09:38:18 -0800
commit024e4ec1856d57bb78c06ec903d29dcf716f5f47 (patch)
tree72c89ea735f2aad2f63f64444ec056d7da8e06ff /fs/pstore
parent850cb82b754c931c570c9cb7f10c9f2181bac617 (diff)
parentfb0af3f2b1b613e5ea75426d454c7e5b1d1eef49 (diff)
downloadlwn-024e4ec1856d57bb78c06ec903d29dcf716f5f47.tar.gz
lwn-024e4ec1856d57bb78c06ec903d29dcf716f5f47.zip
Merge tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux
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://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux: 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
Diffstat (limited to 'fs/pstore')
-rw-r--r--fs/pstore/inode.c18
-rw-r--r--fs/pstore/platform.c35
2 files changed, 46 insertions, 7 deletions
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 67de74ca85f4..e4bcb2cf055a 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -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)
+ kobject_put(pstore_kobj);
+
+out:
+ return err;
}
module_init(init_pstore_fs)
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 5ea2e77ff023..86d1038b5a12 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -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(). */
+ case KMSG_DUMP_PANIC:
+ /* Emergency restart shouldn't be blocked by spin lock. */
+ case KMSG_DUMP_EMERG:
+ return true;
+ default:
+ return false;
+ }
+}
+EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
+
/*
* 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);
oopscount++;
@@ -143,9 +166,9 @@ static void pstore_dump(struct kmsg_dumper *dumper,
total += hsize + len;
part++;
}
- if (in_nmi()) {
+ if (pstore_cannot_block_path(reason)) {
if (is_locked)
- spin_unlock(&psinfo->buf_lock);
+ spin_unlock_irqrestore(&psinfo->buf_lock, flags);
} else
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
}