Three independent kernfs fixes, plus selftest coverage for the paths
they touch. The fixes do not depend on each other.
Patch 1 adds tests for decoding a file handle and for a rename that
keeps the same parent. Patches 2-4:
- kernfs_rename_ns() takes kernfs_rename_lock only when the parent
changes, so two same-parent renames inside one
kernfs_path_from_node() walk can build a path that never existed.
sysfs_warn_dup() is the only caller that can see it.
- __kernfs_fh_to_dentry() creates inodes with no lock, so a decode
racing rmdir() can hash an inode after the removal's ilookup()
pass. The inode keeps i_nlink 1, so no IN_DELETE_SELF is sent.
- kernfs_create_link() reads the target's uid and gid unlocked, so a
chown in between gives the link an owner the target never had.
Patch 1 applies on top of the patch [1] ("selftests: cover kernfs
dentry revalidation") with vfs-7.4.kernfs branch in vfs tree as base.
[1] http://lore.kernel.org/[email protected]
Changes since v1:
http://lore.kernel.org/[email protected]
- Added cover letter
- Used approppriate tags
- Updated commit messages to be more concise
- Replaced data_race() with READ_ONCE() (TJ)
Shakeel Butt (4):
selftests: cover kernfs file handles and same-parent rename
kernfs: take kernfs_rename_lock for same-parent renames too
kernfs: don't lose IN_DELETE_SELF when decoding a file handle
kernfs: fix up the unlocked attribute reads on the creation paths
fs/kernfs/dir.c | 40 ++-
fs/kernfs/kernfs-internal.h | 9 +-
fs/kernfs/mount.c | 32 +-
fs/kernfs/symlink.c | 17 +-
tools/testing/selftests/filesystems/config | 1 +
.../selftests/filesystems/kernfs_test.c | 296 +++++++++++++++++-
6 files changed, 362 insertions(+), 33 deletions(-)
base-commit: 47fc64fb3b433abb9f2242a85ba808ac6f87df22
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2.53.0-Meta
