This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>

Both sysfs_change_owner() and sysfs_file_change_owner() are exported to
modules, but there are no in-kernel module users, so remove the exports
so that crazy out-of-tree drivers don't get the impression that it is
safe to call these functions at all.

Reviewed-by: Rafael J. Wysocki (Intel) <rafael@kernel.org>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Reported-by: Lee Jones <lee@kernel.org>
Reviewed-by: Lee Jones <lee@kernel.org>
Link: https://patch.msgid.link/2026020541-energize-graduate-981a@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When constifying instances of struct attribute, for consistency the
corresponding .is_visible() callback should be adapted, too.
Introduce a temporary transition mechanism until all callbacks are
converted.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://patch.msgid.link/20251029-sysfs-const-attr-prep-v5-4-ea7d745acff4@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 0c17270f9b92 ("net: sysfs: Implement is_visible for
phys_(port_id, port_name, switch_id)"), __dev_change_net_namespace() can
hit WARN_ON() when trying to change owner of a file that isn't visible.
See the trace below:

 WARNING: CPU: 6 PID: 2938 at net/core/dev.c:12410 __dev_change_net_namespace+0xb89/0xc30
 CPU: 6 UID: 0 PID: 2938 Comm: incusd Not tainted 6.17.1-1-mainline #1 PREEMPT(full)  4b783b4a638669fb644857f484487d17cb45ed1f
 Hardware name: Framework Laptop 13 (AMD Ryzen 7040Series)/FRANMDCP07, BIOS 03.07 02/19/2025
 RIP: 0010:__dev_change_net_namespace+0xb89/0xc30
 [...]
 Call Trace:
  <TASK>
  ? if6_seq_show+0x30/0x50
  do_setlink.isra.0+0xc7/0x1270
  ? __nla_validate_parse+0x5c/0xcc0
  ? security_capable+0x94/0x1a0
  rtnl_newlink+0x858/0xc20
  ? update_curr+0x8e/0x1c0
  ? update_entity_lag+0x71/0x80
  ? sched_balance_newidle+0x358/0x450
  ? psi_task_switch+0x113/0x2a0
  ? __pfx_rtnl_newlink+0x10/0x10
  rtnetlink_rcv_msg+0x346/0x3e0
  ? sched_clock+0x10/0x30
  ? __pfx_rtnetlink_rcv_msg+0x10/0x10
  netlink_rcv_skb+0x59/0x110
  netlink_unicast+0x285/0x3c0
  ? __alloc_skb+0xdb/0x1a0
  netlink_sendmsg+0x20d/0x430
  ____sys_sendmsg+0x39f/0x3d0
  ? import_iovec+0x2f/0x40
  ___sys_sendmsg+0x99/0xe0
  __sys_sendmsg+0x8a/0xf0
  do_syscall_64+0x81/0x970
  ? __sys_bind+0xe3/0x110
  ? syscall_exit_work+0x143/0x1b0
  ? do_syscall_64+0x244/0x970
  ? sock_alloc_file+0x63/0xc0
  ? syscall_exit_work+0x143/0x1b0
  ? do_syscall_64+0x244/0x970
  ? alloc_fd+0x12e/0x190
  ? put_unused_fd+0x2a/0x70
  ? do_sys_openat2+0xa2/0xe0
  ? syscall_exit_work+0x143/0x1b0
  ? do_syscall_64+0x244/0x970
  ? exc_page_fault+0x7e/0x1a0
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 [...]
  </TASK>

Fix this by checking is_visible() before trying to touch the attribute.

Fixes: 303a42769c4c ("sysfs: add sysfs_group{s}_change_owner()")
Fixes: 0c17270f9b92 ("net: sysfs: Implement is_visible for phys_(port_id, port_name, switch_id)")
Reported-by: Cynthia <cynthia@kosmx.dev>
Closes: https://lore.kernel.org/netdev/01070199e22de7f8-28f711ab-d3f1-46d9-b9a0-048ab05eb09b-000000@eu-central-1.amazonses.com/
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20251016101456.4087-1-fmancera@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

These transitional fields are now unused and unnecessary.
Remove them and their logic in the sysfs core.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20250811-sysfs-const-bin_attr-final-v4-1-7b6053fd58bb@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The sysfs core handles 'const struct bin_attribute *'.

Adapt the internal references.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20250530-sysfs-const-bin_attr-final-v3-2-724bfcf05b99@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

All users of this field have been migrated to bin_attrs_new.
It can now be constified.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20250313-sysfs-const-bin_attr-final-v2-2-96284e1e88ce@weissschuh.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Using RCU lifetime rules to access kernfs_node::name can avoid the
trouble with kernfs_rename_lock in kernfs_name() and kernfs_path_from_node()
if the fs was created with KERNFS_ROOT_INVARIANT_PARENT. This is usefull
as it allows to implement kernfs_path_from_node() only with RCU
protection and avoiding kernfs_rename_lock. The lock is only required if
the __parent node can be changed and the function requires an unchanged
hierarchy while it iterates from the node to its parent.
The change is needed to allow the lookup of the node's path
(kernfs_path_from_node()) from context which runs always with disabled
preemption and or interrutps even on PREEMPT_RT. The problem is that
kernfs_rename_lock becomes a sleeping lock on PREEMPT_RT.

I went through all ::name users and added the required access for the lookup
with a few extensions:
- rdtgroup_pseudo_lock_create() drops all locks and then uses the name
  later on. resctrl supports rename with different parents. Here I made
  a temporal copy of the name while it is used outside of the lock.

- kernfs_rename_ns() accepts NULL as new_parent. This simplifies
  sysfs_move_dir_ns() where it can set NULL in order to reuse the current
  name.

- kernfs_rename_ns() is only using kernfs_rename_lock if the parents are
  different. All users use either kernfs_rwsem (for stable path view) or
  just RCU for the lookup. The ::name uses always RCU free.

Use RCU lifetime guarantees to access kernfs_node::name.

Suggested-by: Tejun Heo <tj@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Reported-by: syzbot+6ea37e2e6ffccf41a7e6@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/67251dc6.050a0220.529b6.015e.GAE@google.com/
Reported-by: Hillf Danton <hdanton@sina.com>
Closes: https://lore.kernel.org/20241102001224.2789-1-hdanton@sina.com
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20250213145023.2820193-7-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernfs_rename_lock is used to obtain stable kernfs_node::{name|parent}
pointer. This is a preparation to access kernfs_node::parent under RCU
and ensure that the pointer remains stable under the RCU lifetime
guarantees.

For a complete path, as it is done in kernfs_path_from_node(), the
kernfs_rename_lock is still required in order to obtain a stable parent
relationship while computing the relevant node depth. This must not
change while the nodes are inspected in order to build the path.
If the kernfs user never moves the nodes (changes the parent) then the
kernfs_rename_lock is not required and the RCU guarantees are
sufficient. This "restriction" can be set with
KERNFS_ROOT_INVARIANT_PARENT. Otherwise the lock is required.

Rename kernfs_node::parent to kernfs_node::__parent to denote the RCU
access and use RCU accessor while accessing the node.
Make cgroup use KERNFS_ROOT_INVARIANT_PARENT since the parent here can
not change.

Acked-by: Tejun Heo <tj@kernel.org>
Cc: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20250213145023.2820193-6-bigeasy@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>