All of lore.kernel.org
 help / color / mirror / Atom feed
From: Stanislaw Gruszka <sgruszka@redhat.com>
To: "David S. Miller" <davem@davemloft.net>
Cc: linux-wireless@vger.kernel.org, linville@tuxdriver.com,
	netdev@vger.kernel.org, Thomas Graf <tgraf@suug.ch>,
	Stephen Hemminger <shemminger@vyatta.com>,
	rjones@redhat.com, Marcel Holtmann <marcel@holtmann.org>,
	Jeff Layton <jlayton@redhat.com>
Subject: [PATCH 3.11] genetlink: release cb_lock before requesting additional module
Date: Fri, 26 Jul 2013 11:00:10 +0200	[thread overview]
Message-ID: <20130726090010.GA1756@redhat.com> (raw)
In-Reply-To: <20130725105116.043a6b9c@corrin.poochiereds.net>

Requesting external module with cb_lock taken can result in
the deadlock like showed below:

[ 2458.111347] Showing all locks held in the system:
[ 2458.111347] 1 lock held by NetworkManager/582:
[ 2458.111347]  #0:  (cb_lock){++++++}, at: [<ffffffff8162bc79>] genl_rcv+0x19/0x40
[ 2458.111347] 1 lock held by modprobe/603:
[ 2458.111347]  #0:  (cb_lock){++++++}, at: [<ffffffff8162baa5>] genl_lock_all+0x15/0x30

[ 2461.579457] SysRq : Show Blocked State
[ 2461.580103]   task                        PC stack   pid father
[ 2461.580103] NetworkManager  D ffff880034b84500  4040   582      1 0x00000080
[ 2461.580103]  ffff8800197ff720 0000000000000046 00000000001d5340 ffff8800197fffd8
[ 2461.580103]  ffff8800197fffd8 00000000001d5340 ffff880019631700 7fffffffffffffff
[ 2461.580103]  ffff8800197ff880 ffff8800197ff878 ffff880019631700 ffff880019631700
[ 2461.580103] Call Trace:
[ 2461.580103]  [<ffffffff817355f9>] schedule+0x29/0x70
[ 2461.580103]  [<ffffffff81731ad1>] schedule_timeout+0x1c1/0x360
[ 2461.580103]  [<ffffffff810e69eb>] ? mark_held_locks+0xbb/0x140
[ 2461.580103]  [<ffffffff817377ac>] ? _raw_spin_unlock_irq+0x2c/0x50
[ 2461.580103]  [<ffffffff810e6b6d>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[ 2461.580103]  [<ffffffff81736398>] wait_for_completion_killable+0xe8/0x170
[ 2461.580103]  [<ffffffff810b7fa0>] ? wake_up_state+0x20/0x20
[ 2461.580103]  [<ffffffff81095825>] call_usermodehelper_exec+0x1a5/0x210
[ 2461.580103]  [<ffffffff817362ed>] ? wait_for_completion_killable+0x3d/0x170
[ 2461.580103]  [<ffffffff81095cc3>] __request_module+0x1b3/0x370
[ 2461.580103]  [<ffffffff810e6b6d>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[ 2461.580103]  [<ffffffff8162c5c9>] ctrl_getfamily+0x159/0x190
[ 2461.580103]  [<ffffffff8162d8a4>] genl_family_rcv_msg+0x1f4/0x2e0
[ 2461.580103]  [<ffffffff8162d990>] ? genl_family_rcv_msg+0x2e0/0x2e0
[ 2461.580103]  [<ffffffff8162da1e>] genl_rcv_msg+0x8e/0xd0
[ 2461.580103]  [<ffffffff8162b729>] netlink_rcv_skb+0xa9/0xc0
[ 2461.580103]  [<ffffffff8162bc88>] genl_rcv+0x28/0x40
[ 2461.580103]  [<ffffffff8162ad6d>] netlink_unicast+0xdd/0x190
[ 2461.580103]  [<ffffffff8162b149>] netlink_sendmsg+0x329/0x750
[ 2461.580103]  [<ffffffff815db849>] sock_sendmsg+0x99/0xd0
[ 2461.580103]  [<ffffffff810bb58f>] ? local_clock+0x5f/0x70
[ 2461.580103]  [<ffffffff810e96e8>] ? lock_release_non_nested+0x308/0x350
[ 2461.580103]  [<ffffffff815dbc6e>] ___sys_sendmsg+0x39e/0x3b0
[ 2461.580103]  [<ffffffff810565af>] ? kvm_clock_read+0x2f/0x50
[ 2461.580103]  [<ffffffff810218b9>] ? sched_clock+0x9/0x10
[ 2461.580103]  [<ffffffff810bb2bd>] ? sched_clock_local+0x1d/0x80
[ 2461.580103]  [<ffffffff810bb448>] ? sched_clock_cpu+0xa8/0x100
[ 2461.580103]  [<ffffffff810e33ad>] ? trace_hardirqs_off+0xd/0x10
[ 2461.580103]  [<ffffffff810bb58f>] ? local_clock+0x5f/0x70
[ 2461.580103]  [<ffffffff810e3f7f>] ? lock_release_holdtime.part.28+0xf/0x1a0
[ 2461.580103]  [<ffffffff8120fec9>] ? fget_light+0xf9/0x510
[ 2461.580103]  [<ffffffff8120fe0c>] ? fget_light+0x3c/0x510
[ 2461.580103]  [<ffffffff815dd1d2>] __sys_sendmsg+0x42/0x80
[ 2461.580103]  [<ffffffff815dd222>] SyS_sendmsg+0x12/0x20
[ 2461.580103]  [<ffffffff81741ad9>] system_call_fastpath+0x16/0x1b
[ 2461.580103] modprobe        D ffff88000f2c8000  4632   603    602 0x00000080
[ 2461.580103]  ffff88000f04fba8 0000000000000046 00000000001d5340 ffff88000f04ffd8
[ 2461.580103]  ffff88000f04ffd8 00000000001d5340 ffff8800377d4500 ffff8800377d4500
[ 2461.580103]  ffffffff81d0b260 ffffffff81d0b268 ffffffff00000000 ffffffff81d0b2b0
[ 2461.580103] Call Trace:
[ 2461.580103]  [<ffffffff817355f9>] schedule+0x29/0x70
[ 2461.580103]  [<ffffffff81736d4d>] rwsem_down_write_failed+0xed/0x1a0
[ 2461.580103]  [<ffffffff810bb200>] ? update_cpu_load_active+0x10/0xb0
[ 2461.580103]  [<ffffffff8137b473>] call_rwsem_down_write_failed+0x13/0x20
[ 2461.580103]  [<ffffffff8173492d>] ? down_write+0x9d/0xb2
[ 2461.580103]  [<ffffffff8162baa5>] ? genl_lock_all+0x15/0x30
[ 2461.580103]  [<ffffffff8162baa5>] genl_lock_all+0x15/0x30
[ 2461.580103]  [<ffffffff8162cbb3>] genl_register_family+0x53/0x1f0
[ 2461.580103]  [<ffffffffa01dc000>] ? 0xffffffffa01dbfff
[ 2461.580103]  [<ffffffff8162d650>] genl_register_family_with_ops+0x20/0x80
[ 2461.580103]  [<ffffffffa01dc000>] ? 0xffffffffa01dbfff
[ 2461.580103]  [<ffffffffa017fe84>] nl80211_init+0x24/0xf0 [cfg80211]
[ 2461.580103]  [<ffffffffa01dc000>] ? 0xffffffffa01dbfff
[ 2461.580103]  [<ffffffffa01dc043>] cfg80211_init+0x43/0xdb [cfg80211]
[ 2461.580103]  [<ffffffff810020fa>] do_one_initcall+0xfa/0x1b0
[ 2461.580103]  [<ffffffff8105cb93>] ? set_memory_nx+0x43/0x50
[ 2461.580103]  [<ffffffff810f75af>] load_module+0x1c6f/0x27f0
[ 2461.580103]  [<ffffffff810f2c90>] ? store_uevent+0x40/0x40
[ 2461.580103]  [<ffffffff810f82c6>] SyS_finit_module+0x86/0xb0
[ 2461.580103]  [<ffffffff81741ad9>] system_call_fastpath+0x16/0x1b
[ 2461.580103] Sched Debug Version: v0.10, 3.11.0-0.rc1.git4.1.fc20.x86_64 #1

Problem start to happen after adding net-pf-16-proto-16-family-nl80211
alias name to cfg80211 module by below commit (though that commit
itself is perfectly fine):

commit fb4e156886ce6e8309e912d8b370d192330d19d3
Author: Marcel Holtmann <marcel@holtmann.org>
Date:   Sun Apr 28 16:22:06 2013 -0700

    nl80211: Add generic netlink module alias for cfg80211/nl80211

Reported-and-tested-by: Jeff Layton <jlayton@redhat.com>
Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
---
 net/netlink/genetlink.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 2fd6dbe..1076fe1 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -877,8 +877,10 @@ static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info)
 #ifdef CONFIG_MODULES
 		if (res == NULL) {
 			genl_unlock();
+			up_read(&cb_lock);
 			request_module("net-pf-%d-proto-%d-family-%s",
 				       PF_NETLINK, NETLINK_GENERIC, name);
+			down_read(&cb_lock);
 			genl_lock();
 			res = genl_family_find_byname(name);
 		}
-- 
1.7.11.7


  reply	other threads:[~2013-07-26  8:57 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-12 11:49 hung task while plugging in cfg80211 Jeff Layton
2013-07-24  9:59 ` Stanislaw Gruszka
2013-07-25 14:51   ` Jeff Layton
2013-07-25 14:51     ` Jeff Layton
2013-07-26  9:00     ` Stanislaw Gruszka [this message]
2013-07-26 17:08       ` [PATCH 3.11] genetlink: release cb_lock before requesting additional module Pravin Shelar
2013-07-28  5:20         ` David Miller

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20130726090010.GA1756@redhat.com \
    --to=sgruszka@redhat.com \
    --cc=davem@davemloft.net \
    --cc=jlayton@redhat.com \
    --cc=linux-wireless@vger.kernel.org \
    --cc=linville@tuxdriver.com \
    --cc=marcel@holtmann.org \
    --cc=netdev@vger.kernel.org \
    --cc=rjones@redhat.com \
    --cc=shemminger@vyatta.com \
    --cc=tgraf@suug.ch \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.