Commit db23491c authored by Kees Cook's avatar Kees Cook
Browse files

pstore: Convert "records_list" locking to mutex 

The pstorefs internal list lock doesn't need to be a spinlock and will
create problems when trying to access the list in the subsequent patch
that will walk the pstorefs records during pstore_unregister(). Change
this to a mutex to avoid may_sleep() warnings when unregistering devices.

Link: https://lore.kernel.org/lkml/20200506152114.50375-6-keescook@chromium.org/


Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 47af61ff

fs/pstore/inode.c

+7 −10
Original line number Diff line number Diff line
@@ -22,14 +22,13 @@ 
#include <linux/magic.h>

#include <linux/pstore.h>

#include <linux/slab.h>

#include <linux/spinlock.h>

#include <linux/uaccess.h>



#include "internal.h"



#define	PSTORE_NAMELEN	64



static DEFINE_SPINLOCK(records_list_lock);

static DEFINE_MUTEX(records_list_lock);

static LIST_HEAD(records_list);



struct pstore_private {
@@ -192,13 +191,12 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry) 
static void pstore_evict_inode(struct inode *inode)

{

	struct pstore_private	*p = inode->i_private;

	unsigned long		flags;



	clear_inode(inode);

	if (p) {

		spin_lock_irqsave(&records_list_lock, flags);

		mutex_lock(&records_list_lock);

		list_del(&p->list);

		spin_unlock_irqrestore(&records_list_lock, flags);

		mutex_unlock(&records_list_lock);

		free_pstore_private(p);

	}

}
@@ -297,12 +295,11 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record) 
	int			rc = 0;

	char			name[PSTORE_NAMELEN];

	struct pstore_private	*private, *pos;

	unsigned long		flags;

	size_t			size = record->size + record->ecc_notice_size;



	WARN_ON(!inode_is_locked(d_inode(root)));



	spin_lock_irqsave(&records_list_lock, flags);

	mutex_lock(&records_list_lock);

	list_for_each_entry(pos, &records_list, list) {

		if (pos->record->type == record->type &&

		    pos->record->id == record->id &&
@@ -311,7 +308,7 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record) 
			break;

		}

	}

	spin_unlock_irqrestore(&records_list_lock, flags);

	mutex_unlock(&records_list_lock);

	if (rc)

		return rc;
@@ -343,9 +340,9 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record) 


	d_add(dentry, inode);



	spin_lock_irqsave(&records_list_lock, flags);

	mutex_lock(&records_list_lock);

	list_add(&private->list, &records_list);

	spin_unlock_irqrestore(&records_list_lock, flags);

	mutex_unlock(&records_list_lock);



	return 0;

CRA Git | Maintained and supported by SUSTech CRA and CCSE