From: Greg KH <gregkh@linuxfoundation.org>
To: Fernando Fernandez Mancera <fmancera@suse.de>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
kuba@kernel.org, cynthia@kosmx.dev, rafael@kernel.org,
dakr@kernel.org, christian.brauner@ubuntu.com,
edumazet@google.com, pabeni@redhat.com, davem@davemloft.net,
horms@kernel.org
Subject: Re: [PATCH] sysfs: check visibility before changing group attribute ownership
Date: Thu, 16 Oct 2025 16:46:31 +0200 [thread overview]
Message-ID: <2025101604-filing-plenty-ec86@gregkh> (raw)
In-Reply-To: <20251016101456.4087-1-fmancera@suse.de>
On Thu, Oct 16, 2025 at 12:14:56PM +0200, Fernando Fernandez Mancera wrote:
> 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()")
> 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>
> ---
> fs/sysfs/group.c | 26 +++++++++++++++++++++-----
> 1 file changed, 21 insertions(+), 5 deletions(-)
Nice, thanks! This has been tested, right?
thanks,
greg k-h
next prev parent reply other threads:[~2025-10-16 14:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-16 10:14 [PATCH] sysfs: check visibility before changing group attribute ownership Fernando Fernandez Mancera
2025-10-16 14:46 ` Greg KH [this message]
2025-10-16 15:31 ` Cynthia
2025-10-16 23:17 ` Fernando Fernandez Mancera
2025-10-16 15:38 ` Jakub Kicinski
2025-10-16 23:30 ` Fernando Fernandez Mancera
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