Commit 609e28bb authored by Kees Cook's avatar Kees Cook

pstore: Remove filesystem records when backend is unregistered

If a backend was unloaded without having first removed all its
associated records in pstorefs, subsequent removals would crash while
attempting to call into the now missing backend. Add automatic removal
from the tree in pstore_unregister(), so that no references to the
backend remain.
Reported-by: default avatarLuis Henriques <lhenriques@suse.com>
Link: https://lore.kernel.org/lkml/87o8yrmv69.fsf@suse.com
Link: https://lore.kernel.org/lkml/20200506152114.50375-11-keescook@chromium.org/Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 78c83c82
...@@ -36,6 +36,7 @@ static struct super_block *pstore_sb; ...@@ -36,6 +36,7 @@ static struct super_block *pstore_sb;
struct pstore_private { struct pstore_private {
struct list_head list; struct list_head list;
struct dentry *dentry;
struct pstore_record *record; struct pstore_record *record;
size_t total_size; size_t total_size;
}; };
...@@ -191,6 +192,7 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry) ...@@ -191,6 +192,7 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
list_del_init(&p->list); list_del_init(&p->list);
else else
rc = -ENOENT; rc = -ENOENT;
p->dentry = NULL;
mutex_unlock(&records_list_lock); mutex_unlock(&records_list_lock);
if (rc) if (rc)
return rc; return rc;
...@@ -306,6 +308,35 @@ static struct dentry *psinfo_lock_root(void) ...@@ -306,6 +308,35 @@ static struct dentry *psinfo_lock_root(void)
return root; return root;
} }
int pstore_put_backend_records(struct pstore_info *psi)
{
struct pstore_private *pos, *tmp;
struct dentry *root;
int rc = 0;
root = psinfo_lock_root();
if (!root)
return 0;
mutex_lock(&records_list_lock);
list_for_each_entry_safe(pos, tmp, &records_list, list) {
if (pos->record->psi == psi) {
list_del_init(&pos->list);
rc = simple_unlink(d_inode(root), pos->dentry);
if (WARN_ON(rc))
break;
d_drop(pos->dentry);
dput(pos->dentry);
pos->dentry = NULL;
}
}
mutex_unlock(&records_list_lock);
inode_unlock(d_inode(root));
return rc;
}
/* /*
* Make a regular file in the root directory of our file system. * Make a regular file in the root directory of our file system.
* Load it up with "size" bytes of data from "buf". * Load it up with "size" bytes of data from "buf".
...@@ -352,6 +383,7 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record) ...@@ -352,6 +383,7 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
if (!dentry) if (!dentry)
goto fail_private; goto fail_private;
private->dentry = dentry;
private->record = record; private->record = record;
inode->i_size = private->total_size = size; inode->i_size = private->total_size = size;
inode->i_private = private; inode->i_private = private;
......
...@@ -31,6 +31,7 @@ extern void pstore_set_kmsg_bytes(int); ...@@ -31,6 +31,7 @@ extern void pstore_set_kmsg_bytes(int);
extern void pstore_get_records(int); extern void pstore_get_records(int);
extern void pstore_get_backend_records(struct pstore_info *psi, extern void pstore_get_backend_records(struct pstore_info *psi,
struct dentry *root, int quiet); struct dentry *root, int quiet);
extern int pstore_put_backend_records(struct pstore_info *psi);
extern int pstore_mkfile(struct dentry *root, extern int pstore_mkfile(struct dentry *root,
struct pstore_record *record); struct pstore_record *record);
extern void pstore_record_init(struct pstore_record *record, extern void pstore_record_init(struct pstore_record *record,
......
...@@ -657,6 +657,9 @@ void pstore_unregister(struct pstore_info *psi) ...@@ -657,6 +657,9 @@ void pstore_unregister(struct pstore_info *psi)
del_timer_sync(&pstore_timer); del_timer_sync(&pstore_timer);
flush_work(&pstore_work); flush_work(&pstore_work);
/* Remove all backend records from filesystem tree. */
pstore_put_backend_records(psi);
free_buf_for_compression(); free_buf_for_compression();
psinfo = NULL; psinfo = NULL;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment