sysfs: check visibility before changing group attribute ownership

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>

0 files changed, 0 insertions, 0 deletions