Re: [PATCH driver-core-linus] kernfs: make kernfs_deactivate() honorKERNFS_LOCKDEP flag

From: Jiri Kosina
Date: Thu Jan 30 2014 - 05:43:09 EST


On Wed, 29 Jan 2014, Tejun Heo wrote:

> kernfs_deactivate() forgot to check whether KERNFS_LOCKDEP is set
> before performing lockdep annotations and ends up feeding
> uninitialized lockdep_map to lockdep triggering warning like the
> following on USB stick hotunplug.
>
> usb 1-2: USB disconnect, device number 2
> INFO: trying to register non-static key.
> the code is fine but needs lockdep annotation.
> turning off the locking correctness validator.
> CPU: 1 PID: 62 Comm: khubd Not tainted 3.13.0-work+ #82
> Hardware name: empty empty/S3992, BIOS 080011 10/26/2007
> ffff880065ca7f60 ffff88013a4ffa08 ffffffff81cfb6bd 0000000000000002
> ffff88013a4ffac8 ffffffff810f8530 ffff88013a4fc710 0000000000000002
> ffff880100000000 ffffffff82a3db50 0000000000000001 ffff88013a4fc710
> Call Trace:
> [<ffffffff81cfb6bd>] dump_stack+0x4e/0x7a
> [<ffffffff810f8530>] __lock_acquire+0x1910/0x1e70
> [<ffffffff810f931a>] lock_acquire+0x9a/0x1d0
> [<ffffffff8127c75e>] kernfs_deactivate+0xee/0x130
> [<ffffffff8127d4c8>] kernfs_addrm_finish+0x38/0x60
> [<ffffffff8127d701>] kernfs_remove_by_name_ns+0x51/0xa0
> [<ffffffff8127b4f1>] remove_files.isra.1+0x41/0x80
> [<ffffffff8127b7e7>] sysfs_remove_group+0x47/0xa0
> [<ffffffff8127b873>] sysfs_remove_groups+0x33/0x50
> [<ffffffff8177d66d>] device_remove_attrs+0x4d/0x80
> [<ffffffff8177e25e>] device_del+0x12e/0x1d0
> [<ffffffff819722c2>] usb_disconnect+0x122/0x1a0
> [<ffffffff819749b5>] hub_thread+0x3c5/0x1290
> [<ffffffff810c6a6d>] kthread+0xed/0x110
> [<ffffffff81d0a56c>] ret_from_fork+0x7c/0xb0
>
> Fix it by making kernfs_deactivate() perform lockdep annotations only
> if KERNFS_LOCKDEP is set.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Reported-by: Fabio Estevam <festevam@xxxxxxxxx>
> Reported-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

I reported it here:

https://lkml.org/lkml/2014/1/22/217

The patch fixes it for me as well.

Reported-and-tested-by: Jiri Kosina <jkosina@xxxxxxx>

Thanks,

--
Jiri Kosina
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/