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authorChen Zhongjin <chenzhongjin@huawei.com>2022-10-17 09:42:30 +0800
committerChristoph Hellwig <hch@lst.de>2022-12-02 11:11:22 +0100
commitc65234b283a65cfbfc94619655e820a5e55199eb (patch)
treea68c9c53f806af42e3f9c6514f94514658974ce9 /fs/configfs
parentb7b275e60bcd5f89771e865a8239325f86d9927d (diff)
configfs: fix possible memory leak in configfs_create_dir()
kmemleak reported memory leaks in configfs_create_dir(): unreferenced object 0xffff888009f6af00 (size 192): comm "modprobe", pid 3777, jiffies 4295537735 (age 233.784s) backtrace: kmem_cache_alloc (mm/slub.c:3250 mm/slub.c:3256 mm/slub.c:3263 mm/slub.c:3273) new_fragment (./include/linux/slab.h:600 fs/configfs/dir.c:163) configfs_register_subsystem (fs/configfs/dir.c:1857) basic_write (drivers/hwtracing/stm/p_basic.c:14) stm_p_basic do_one_initcall (init/main.c:1296) do_init_module (kernel/module/main.c:2455) ... unreferenced object 0xffff888003ba7180 (size 96): comm "modprobe", pid 3777, jiffies 4295537735 (age 233.784s) backtrace: kmem_cache_alloc (mm/slub.c:3250 mm/slub.c:3256 mm/slub.c:3263 mm/slub.c:3273) configfs_new_dirent (./include/linux/slab.h:723 fs/configfs/dir.c:194) configfs_make_dirent (fs/configfs/dir.c:248) configfs_create_dir (fs/configfs/dir.c:296) configfs_attach_group.isra.28 (fs/configfs/dir.c:816 fs/configfs/dir.c:852) configfs_register_subsystem (fs/configfs/dir.c:1881) basic_write (drivers/hwtracing/stm/p_basic.c:14) stm_p_basic do_one_initcall (init/main.c:1296) do_init_module (kernel/module/main.c:2455) ... This is because the refcount is not correct in configfs_make_dirent(). For normal stage, the refcount is changing as: configfs_register_subsystem() configfs_create_dir() configfs_make_dirent() configfs_new_dirent() # set s_count = 1 dentry->d_fsdata = configfs_get(sd); # s_count = 2 ... configfs_unregister_subsystem() configfs_remove_dir() remove_dir() configfs_remove_dirent() # s_count = 1 dput() ... *dentry_unlink_inode()* configfs_d_iput() # s_count = 0, release However, if we failed in configfs_create(): configfs_register_subsystem() configfs_create_dir() configfs_make_dirent() # s_count = 2 ... configfs_create() # fail ->out_remove: configfs_remove_dirent(dentry) configfs_put(sd) # s_count = 1 return PTR_ERR(inode); There is no inode in the error path, so the configfs_d_iput() is lost and makes sd and fragment memory leaked. To fix this, when we failed in configfs_create(), manually call configfs_put(sd) to keep the refcount correct. Fixes: 7063fbf22611 ("[PATCH] configfs: User-driven configuration filesystem") Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs/configfs')
-rw-r--r--fs/configfs/dir.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index d1f9d2632202..ec6519e1ca3b 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -316,6 +316,7 @@ static int configfs_create_dir(struct config_item *item, struct dentry *dentry,
return 0;
out_remove:
+ configfs_put(dentry->d_fsdata);
configfs_remove_dirent(dentry);
return PTR_ERR(inode);
}
@@ -382,6 +383,7 @@ int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
return 0;
out_remove:
+ configfs_put(dentry->d_fsdata);
configfs_remove_dirent(dentry);
return PTR_ERR(inode);
}