[PATCH AUTOSEL 4.14 4/9] nilfs2: fix memory leak in nilfs_sysfs_create_device_group

[PATCH AUTOSEL 4.14 4/9] nilfs2: fix memory leak in nilfs_sysfs_create_device_group

[Sasha Levin]

From: Nanyong Sun <sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>

[ Upstream commit 5f5dec07aca7067216ed4c1342e464e7307a9197 ]

Patch series "nilfs2: fix incorrect usage of kobject".

This patchset from Nanyong Sun fixes memory leak issues and a NULL
pointer dereference issue caused by incorrect usage of kboject in nilfs2
sysfs implementation.

This patch (of 6):

Reported by syzkaller:

  BUG: memory leak
  unreferenced object 0xffff888100ca8988 (size 8):
  comm "syz-executor.1", pid 1930, jiffies 4294745569 (age 18.052s)
  hex dump (first 8 bytes):
  6c 6f 6f 70 31 00 ff ff loop1...
  backtrace:
    kstrdup+0x36/0x70 mm/util.c:60
    kstrdup_const+0x35/0x60 mm/util.c:83
    kvasprintf_const+0xf1/0x180 lib/kasprintf.c:48
    kobject_set_name_vargs+0x56/0x150 lib/kobject.c:289
    kobject_add_varg lib/kobject.c:384 [inline]
    kobject_init_and_add+0xc9/0x150 lib/kobject.c:473
    nilfs_sysfs_create_device_group+0x150/0x7d0 fs/nilfs2/sysfs.c:986
    init_nilfs+0xa21/0xea0 fs/nilfs2/the_nilfs.c:637
    nilfs_fill_super fs/nilfs2/super.c:1046 [inline]
    nilfs_mount+0x7b4/0xe80 fs/nilfs2/super.c:1316
    legacy_get_tree+0x105/0x210 fs/fs_context.c:592
    vfs_get_tree+0x8e/0x2d0 fs/super.c:1498
    do_new_mount fs/namespace.c:2905 [inline]
    path_mount+0xf9b/0x1990 fs/namespace.c:3235
    do_mount+0xea/0x100 fs/namespace.c:3248
    __do_sys_mount fs/namespace.c:3456 [inline]
    __se_sys_mount fs/namespace.c:3433 [inline]
    __x64_sys_mount+0x14b/0x1f0 fs/namespace.c:3433
    do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80
    entry_SYSCALL_64_after_hwframe+0x44/0xae

If kobject_init_and_add return with error, then the cleanup of kobject
is needed because memory may be allocated in kobject_init_and_add
without freeing.

And the place of cleanup_dev_kobject should use kobject_put to free the
memory associated with the kobject.  As the section "Kobject removal" of
"Documentation/core-api/kobject.rst" says, kobject_del() just makes the
kobject "invisible", but it is not cleaned up.  And no more cleanup will
do after cleanup_dev_kobject, so kobject_put is needed here.

Link: https://lkml.kernel.org/r/1625651306-10829-1-git-send-email-konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Link: https://lkml.kernel.org/r/1625651306-10829-2-git-send-email-konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Reported-by: Hulk Robot <hulkci-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Link: https://lkml.kernel.org/r/20210629022556.3985106-2-sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org
Signed-off-by: Nanyong Sun <sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Signed-off-by: Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Signed-off-by: Sasha Levin <sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 fs/nilfs2/sysfs.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index e9903bceb2bf..a35978bf8395 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -1010,7 +1010,7 @@ int nilfs_sysfs_create_device_group(struct super_block *sb)
 	err = kobject_init_and_add(&nilfs->ns_dev_kobj, &nilfs_dev_ktype, NULL,
 				    "%s", sb->s_id);
 	if (err)
-		goto free_dev_subgroups;
+		goto cleanup_dev_kobject;
 
 	err = nilfs_sysfs_create_mounted_snapshots_group(nilfs);
 	if (err)
@@ -1047,9 +1047,7 @@ int nilfs_sysfs_create_device_group(struct super_block *sb)
 	nilfs_sysfs_delete_mounted_snapshots_group(nilfs);
 
 cleanup_dev_kobject:
-	kobject_del(&nilfs->ns_dev_kobj);
-
-free_dev_subgroups:
+	kobject_put(&nilfs->ns_dev_kobj);
 	kfree(nilfs->ns_dev_subgroups);
 
 failed_create_device_group:
-- 
2.30.2

[PATCH AUTOSEL 4.14 5/9] nilfs2: fix NULL pointer in nilfs_##name##_attr_release

[Sasha Levin]

From: Nanyong Sun <sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>

[ Upstream commit dbc6e7d44a514f231a64d9d5676e001b660b6448 ]

In nilfs_##name##_attr_release, kobj->parent should not be referenced
because it is a NULL pointer.  The release() method of kobject is always
called in kobject_put(kobj), in the implementation of kobject_put(), the
kobj->parent will be assigned as NULL before call the release() method.
So just use kobj to get the subgroups, which is more efficient and can fix
a NULL pointer reference problem.

Link: https://lkml.kernel.org/r/20210629022556.3985106-3-sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org
Link: https://lkml.kernel.org/r/1625651306-10829-3-git-send-email-konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Signed-off-by: Nanyong Sun <sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Signed-off-by: Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Signed-off-by: Sasha Levin <sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 fs/nilfs2/sysfs.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index a35978bf8395..027a50bc0765 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -73,11 +73,9 @@ static const struct sysfs_ops nilfs_##name##_attr_ops = { \
 #define NILFS_DEV_INT_GROUP_TYPE(name, parent_name) \
 static void nilfs_##name##_attr_release(struct kobject *kobj) \
 { \
-	struct nilfs_sysfs_##parent_name##_subgroups *subgroups; \
-	struct the_nilfs *nilfs = container_of(kobj->parent, \
-						struct the_nilfs, \
-						ns_##parent_name##_kobj); \
-	subgroups = nilfs->ns_##parent_name##_subgroups; \
+	struct nilfs_sysfs_##parent_name##_subgroups *subgroups = container_of(kobj, \
+						struct nilfs_sysfs_##parent_name##_subgroups, \
+						sg_##name##_kobj); \
 	complete(&subgroups->sg_##name##_kobj_unregister); \
 } \
 static struct kobj_type nilfs_##name##_ktype = { \
-- 
2.30.2

[PATCH AUTOSEL 4.14 6/9] nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group

[Sasha Levin]

From: Nanyong Sun <sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>

[ Upstream commit 24f8cb1ed057c840728167dab33b32e44147c86f ]

If kobject_init_and_add return with error, kobject_put() is needed here to
avoid memory leak, because kobject_init_and_add may return error without
freeing the memory associated with the kobject it allocated.

Link: https://lkml.kernel.org/r/20210629022556.3985106-4-sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org
Link: https://lkml.kernel.org/r/1625651306-10829-4-git-send-email-konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Signed-off-by: Nanyong Sun <sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Signed-off-by: Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Signed-off-by: Sasha Levin <sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 fs/nilfs2/sysfs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index 027a50bc0765..eab7bd68da12 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -101,8 +101,8 @@ static int nilfs_sysfs_create_##name##_group(struct the_nilfs *nilfs) \
 	err = kobject_init_and_add(kobj, &nilfs_##name##_ktype, parent, \
 				    #name); \
 	if (err) \
-		return err; \
-	return 0; \
+		kobject_put(kobj); \
+	return err; \
 } \
 static void nilfs_sysfs_delete_##name##_group(struct the_nilfs *nilfs) \
 { \
-- 
2.30.2

[PATCH AUTOSEL 4.14 7/9] nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group

[Sasha Levin]

From: Nanyong Sun <sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>

[ Upstream commit a3e181259ddd61fd378390977a1e4e2316853afa ]

The kobject_put() should be used to cleanup the memory associated with the
kobject instead of kobject_del.  See the section "Kobject removal" of
"Documentation/core-api/kobject.rst".

Link: https://lkml.kernel.org/r/20210629022556.3985106-5-sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org
Link: https://lkml.kernel.org/r/1625651306-10829-5-git-send-email-konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Signed-off-by: Nanyong Sun <sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Signed-off-by: Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Signed-off-by: Sasha Levin <sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 fs/nilfs2/sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index eab7bd68da12..31eed118d0ce 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -106,7 +106,7 @@ static int nilfs_sysfs_create_##name##_group(struct the_nilfs *nilfs) \
 } \
 static void nilfs_sysfs_delete_##name##_group(struct the_nilfs *nilfs) \
 { \
-	kobject_del(&nilfs->ns_##parent_name##_subgroups->sg_##name##_kobj); \
+	kobject_put(&nilfs->ns_##parent_name##_subgroups->sg_##name##_kobj); \
 }
 
 /************************************************************************
-- 
2.30.2

[PATCH AUTOSEL 4.14 9/9] nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group

[Sasha Levin]

From: Nanyong Sun <sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>

[ Upstream commit 17243e1c3072b8417a5ebfc53065d0a87af7ca77 ]

kobject_put() should be used to cleanup the memory associated with the
kobject instead of kobject_del().  See the section "Kobject removal" of
"Documentation/core-api/kobject.rst".

Link: https://lkml.kernel.org/r/20210629022556.3985106-7-sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org
Link: https://lkml.kernel.org/r/1625651306-10829-7-git-send-email-konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
Signed-off-by: Nanyong Sun <sunnanyong-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Signed-off-by: Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Signed-off-by: Sasha Levin <sashal-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 fs/nilfs2/sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index 28f5572c6aae..33fba75aa9f3 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -224,7 +224,7 @@ int nilfs_sysfs_create_snapshot_group(struct nilfs_root *root)
 
 void nilfs_sysfs_delete_snapshot_group(struct nilfs_root *root)
 {
-	kobject_del(&root->snapshot_kobj);
+	kobject_put(&root->snapshot_kobj);
 }
 
 /************************************************************************
-- 
2.30.2

[PATCH AUTOSEL 4.14 8/9] nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group

[Sasha Levin]

From: Nanyong Sun <sunnanyong@huawei.com>

[ Upstream commit b2fe39c248f3fa4bbb2a20759b4fdd83504190f7 ]

If kobject_init_and_add returns with error, kobject_put() is needed here
to avoid memory leak, because kobject_init_and_add may return error
without freeing the memory associated with the kobject it allocated.

Link: https://lkml.kernel.org/r/20210629022556.3985106-6-sunnanyong@huawei.com
Link: https://lkml.kernel.org/r/1625651306-10829-6-git-send-email-konishi.ryusuke@gmail.com
Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/nilfs2/sysfs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index 31eed118d0ce..28f5572c6aae 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -217,9 +217,9 @@ int nilfs_sysfs_create_snapshot_group(struct nilfs_root *root)
 	}
 
 	if (err)
-		return err;
+		kobject_put(&root->snapshot_kobj);
 
-	return 0;
+	return err;
 }
 
 void nilfs_sysfs_delete_snapshot_group(struct nilfs_root *root)
-- 
2.30.2