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SubjectRe: BUG: All network processes hang (brcmsmac/wpa_supplicant)
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Le mardi 18 octobre 2011 à 13:14 +0200, Nico Schottelius a écrit :
> Dear LKML,
>
> there is a rather nasty bug in all recent kernels (probably older as
> well):
>
> If wpa_supplicant looses the connection to an AP, all network calls
> hang, uninterruptle.
>
> This is a snippet of running fetchmail after the problem started:
>
> socket(PF_NETLINK, SOCK_RAW, 0) = 4
> bind(4, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 0
> getsockname(4, {sa_family=AF_NETLINK, pid=9734, groups=00000000}, [12]) = 0
> sendto(4, "\24\0\0\0\26\0\1\3\225\\\235N\0\0\0\0\0\0\0\0", 20, 0, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12
>
> [12:59] brief:linux-2.6% ps aux | grep fetchmail
> nico 9063 0.0 0.0 20652 1492 pts/3 D+ 12:55 0:00 fetchmail
> nico 9564 0.0 0.0 20652 1496 pts/15 D+ 13:01 0:00 fetchmail
> nico 9731 0.0 0.0 4288 724 pts/34 S+ 13:01 0:00 strace -fF fetchmail
> nico 9734 0.0 0.0 20652 1492 pts/34 D+ 13:01 0:00 fetchmail
>
> This is particular nasty, because even calling "sudo -i" does a sendto() call
> and thus hangs, as well as trying to send this mail with sendmail makes mutt hang.
>
> I've seen that on stock Archlinux kernel (linux 3.0.6-2),
> latest from Linus (v3.1-rc9-93-ga84a79e), merged trees from Keith and Jiri
> (3.1.0-rc6-gbee709a).
>
> Listing of hanging processes:
>
> [13:05] brief:linux-2.6% ps aux | grep D
> USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
> root 9056 0.2 0.0 0 0 ? D 12:54 0:02 [kworker/u:0]
> nico 9063 0.0 0.0 20652 1492 pts/3 D+ 12:55 0:00 fetchmail
> nico 9066 0.0 0.0 16548 1180 ? D 12:56 0:00 sendmail -oem -oi -f ME@inf.ethz.ch -- RECIPIENT
> root 9067 0.0 0.0 6060 320 pts/14 DN 12:56 0:00 ip r
> root 9124 0.0 0.0 6060 320 pts/14 DN 12:57 0:00 ip r add 192.168.42.1/24 dev lo
> root 9390 0.0 0.0 11996 784 pts/12 D+ 13:01 0:00 sudo -i
> nico 9564 0.0 0.0 20652 1496 pts/15 D+ 13:01 0:00 fetchmail
> nico 9734 0.0 0.0 20652 1492 pts/34 D+ 13:01 0:00 fetchmail
> root 12304 0.0 0.0 28624 2228 ? Ds 09:16 0:00 wpa_supplicant -B -P /run/wpa_supplicant_wlan0.pid -i wlan0 -D nl80211,wext -c /run/network//wpa.wlan0/wpa.conf
> [13:07] brief:linux-2.6%
>
> The hardware is again the (in)famous MacBook Air 4,2, so I imagine this may be
> related to brcmsmac.
>
> Attached are config, dmesg, lsmod.


Must be a mutex_unlock(some_mltex) missing somewhere.

Then later, a process holding RTNL is blocking on mutex_lock(some_mutex)

Try a "CONFIG_LOCKDEP=y" enabled build




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