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    Subject[PATCH AUTOSEL 5.10 12/16] nilfs2: fix NULL pointer in nilfs_##name##_attr_release
    Date
    From: Nanyong Sun <sunnanyong@huawei.com>

    [ 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@huawei.com
    Link: https://lkml.kernel.org/r/1625651306-10829-3-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 | 8 +++-----
    1 file changed, 3 insertions(+), 5 deletions(-)

    diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
    index b6a48492fed2..43f660beb9b4 100644
    --- a/fs/nilfs2/sysfs.c
    +++ b/fs/nilfs2/sysfs.c
    @@ -64,11 +64,9 @@ 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
    \
     
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      Last update: 2021-09-14 00:40    [W:4.487 / U:0.004 seconds]
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