From: Emeltchenko Andrei <Andrei.Emeltchenko.news@gmail.com>
To: linux-bluetooth@vger.kernel.org
Subject: [RESEND 1/3] Bluetooth: Use cancel_work instead of cancel_work_sync
Date: Tue, 31 Jan 2012 10:43:02 +0200 [thread overview]
Message-ID: <1327999384-16094-2-git-send-email-Andrei.Emeltchenko.news@gmail.com> (raw)
In-Reply-To: <1327999384-16094-1-git-send-email-Andrei.Emeltchenko.news@gmail.com>
From: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Fix deadlock when cancelling delayed work.
[ 584.676126] ======================================================
[ 584.676126] [ INFO: possible circular locking dependency detected ]
[ 584.676126] 3.2.0-rc2niko+ #44
[ 584.676126] -------------------------------------------------------
[ 584.676126] kworker/u:1/30 is trying to acquire lock:
[ 584.676126] (&hdev->lock){+.+.+.}, at: [<f81f001c>] hci_conn_timeout+0x6c/0x190 [bluetooth]
[ 584.676126]
[ 584.676126] but task is already holding lock:
[ 584.676126] ((&(&conn->disc_work)->work)){+.+...}, at: [<c1065a78>] process_one_work+0x108/0x460
[ 584.676126]
[ 584.676126] which lock already depends on the new lock.
[ 584.676126]
[ 584.676126]
[ 584.676126] the existing dependency chain (in reverse order) is:
[ 584.676126]
[ 584.676126] -> #1 ((&(&conn->disc_work)->work)){+.+...}:
[ 584.676126] [<c1086748>] lock_acquire+0x88/0x110
[ 584.676126] [<c1066041>] wait_on_work+0x61/0x210
[ 584.676126] [<c106630a>] __cancel_work_timer+0x6a/0x110
[ 584.676126] [<c10663c0>] cancel_delayed_work_sync+0x10/0x20
[ 584.676126] [<f81f935b>] hci_event_packet+0x3b2b/0x4610 [bluetooth]
[ 584.676126] [<f81ea78e>] hci_rx_work+0x20e/0x4c0 [bluetooth]
[ 584.676126] [<c1065aec>] process_one_work+0x17c/0x460
[ 584.676126] [<c10672e4>] worker_thread+0x124/0x2c0
[ 584.676126] [<c106be44>] kthread+0x84/0x90
[ 584.676126] [<c1567f42>] kernel_thread_helper+0x6/0x10
[ 584.676126]
[ 584.676126] -> #0 (&hdev->lock){+.+.+.}:
[ 584.676126] [<c10852cd>] __lock_acquire+0xc0d/0x1ab0
[ 584.676126] [<c1086748>] lock_acquire+0x88/0x110
[ 584.676126] [<c155de50>] mutex_lock_nested+0x70/0x320
[ 584.676126] [<f81f001c>] hci_conn_timeout+0x6c/0x190 [bluetooth]
[ 584.676126] [<c1065aec>] process_one_work+0x17c/0x460
[ 584.676126] [<c10672e4>] worker_thread+0x124/0x2c0
[ 584.676126] [<c106be44>] kthread+0x84/0x90
[ 584.676126] [<c1567f42>] kernel_thread_helper+0x6/0x10
[ 584.676126]
[ 584.676126] other info that might help us debug this:
[ 584.676126]
[ 584.676126] Possible unsafe locking scenario:
[ 584.676126]
[ 584.676126] CPU0 CPU1
[ 584.676126] ---- ----
[ 584.676126] lock((&(&conn->disc_work)->work));
[ 584.676126] lock(&hdev->lock);
[ 584.676126] lock((&(&conn->disc_work)->work));
[ 584.676126] lock(&hdev->lock);
[ 584.676126]
[ 584.676126] *** DEADLOCK ***
[ 584.676126]
[ 584.676126] 2 locks held by kworker/u:1/30:
[ 584.676126] #0: (hdev->name){.+.+.+}, at: [<c1065a78>] process_one_work+0x108/0x460
[ 584.676126] #1: ((&(&conn->disc_work)->work)){+.+...}, at: [<c1065a78>] process_one_work+0x108/0x460
Signed-off-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
---
v2 - use cancel_delayed_work instead of cancel_delayed_work_sync following
recommendation from Ulisses Furquim
---
net/bluetooth/hci_conn.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 67c94c4..7ec6e54 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -433,7 +433,7 @@ int hci_conn_del(struct hci_conn *conn)
del_timer(&conn->idle_timer);
- cancel_delayed_work_sync(&conn->disc_work);
+ cancel_delayed_work(&conn->disc_work);
del_timer(&conn->auto_accept_timer);
--
1.7.4.1
next prev parent reply other threads:[~2012-01-31 8:43 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-31 8:43 [RESEND 0/3] Fixes kernel crashes and warnings Emeltchenko Andrei
2012-01-31 8:43 ` Emeltchenko Andrei [this message]
2012-01-31 12:31 ` [RESEND 1/3] Bluetooth: Use cancel_work instead of cancel_work_sync Andre Guedes
2012-01-31 13:02 ` Emeltchenko Andrei
2012-01-31 15:11 ` Marcel Holtmann
2012-01-31 15:41 ` Ulisses Furquim
2012-01-31 15:58 ` Marcel Holtmann
2012-01-31 17:49 ` Ulisses Furquim
2012-02-01 13:32 ` Emeltchenko Andrei
2012-02-01 15:53 ` Marcel Holtmann
2012-02-02 8:34 ` Emeltchenko Andrei
2012-01-31 15:07 ` Marcel Holtmann
2012-01-31 8:43 ` [RESEND 2/3] Bluetooth: Use list _safe deleting from conn_hash_list Emeltchenko Andrei
2012-01-31 15:07 ` Marcel Holtmann
2012-01-31 8:43 ` [RESEND 3/3] Bluetooth: Use list _safe deleting from conn chan_list Emeltchenko Andrei
2012-01-31 15:08 ` Marcel Holtmann
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