On 29/06/15 10:20, Tom Hughes wrote:
> On 29/06/15 09:30, Tom Hughes wrote:
>> On 29/06/15 09:14, Johannes Berg wrote:
>>> On Sat, 2015-06-27 at 16:34 +0100, Tom Hughes wrote:
>>>>
>>>> Interestingly from what I can see this is trying to create a file
>>>> for the station at a path something like:
>>>>
>>>> ieee80211/phy0/netdev:XXXX/stations/XXXXXX
>>>
>>> indeed.
>>>
>>>> but in my (currently working) boot under 4.0.4 there is no netdev
>>>> directory under phy0 in debugfs... but then maybe that is the problem
>>>> as well if the inode pointer was null?
>>>>
>>>
>>> This is pretty strange - if the dentry pointer (sdata
>>> ->debugfs.subdir_stations) was NULL or an ERR_PTR(), the code would
>>> return pretty much immediately.
>>>
>>> So it looks like that pointer is valid, but it's ->d_inode was NULL?
>>>
>>> I'm not really sure how that could happen.
>>
>> Indeed I'm a bit puzzled...
>
> It looks like hostapd has something to do with it... If I stop hostapd and
> remove ath9k and then reprobe it then the netdev dir appears:
>
> gosford [~] % sudo modprobe ath9k
> gosford [~] % sudo ls /sys/kernel/debug/ieee80211/phy1
> ath9k long_retry_limit reset user_power
> fragmentation_threshold netdev:wlp2s0 rts_threshold wep_iv
> ht40allow_map power short_retry_limit
> hwflags queues statistics
> keys rc total_ps_buffered
>
> Then I start hostapd and it vanishes:
...and you also need to have selinux in enforcing mode.
It appears hostapd is trying to do something with debugfs and is
being denied directory search access:
time->Mon Jun 29 10:39:34 2015
type=PROCTITLE msg=audit(1435570774.085:16533): proctitle=2F7573722F7362696E2F686F7374617064002F6574632F686F73746170642F686F73746170642E636F6E66002D50002F72756E2F686F73746170642E706964002D42
type=SYSCALL msg=audit(1435570774.085:16533): arch=40000003 syscall=102 success=yes exit=36 a0=10 a1=bf93c910 a2=b777d000 a3=90517e8 items=0 ppid=1 pid=7241 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="hostapd" exe="/usr/sbin/hostapd" subj=system_u:system_r:hostapd_t:s0 key=(null)
type=AVC msg=audit(1435570774.085:16533): avc: denied { search } for pid=7241 comm="hostapd" name="phy7" dev="debugfs" ino=5626659 scontext=system_u:system_r:hostapd_t:s0 tcontext=system_u:object_r:debugfs_t:s0 tclass=dir permissive=1
It must then do something that breaks the kernel...
Tom
--
Tom Hughes (tom@xxxxxxxxxx)
http://compton.nu/
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