Bluetooth hci uses ordered HIGHPRI, MEM_RECLAIM workqueues. It's
likely that the flags came from mechanical conversion from
create_singlethread_workqueue(). Bluetooth shouldn't be depended upon
for memory reclaim and the spurious MEM_RECLAIM flag can trigger the
following warning. Remove WQ_MEM_RECLAIM and convert to
alloc_ordered_workqueue() while at it.
workqueue: WQ_MEM_RECLAIM hci0:hci_power_off is flushing !WQ_MEM_RECLAIM events:btusb_work
------------[ cut here ]------------
WARNING: CPU: 2 PID: 14231 at /home/brodo/local/kernel/git/linux/kernel/workqueue.c:2423 check_flush_dependency+0xb3/0x100
Modules linked in:
CPU: 2 PID: 14231 Comm: kworker/u9:4 Not tainted 4.12.0-rc6+ #3
Hardware name: Dell Inc. XPS 13 9343/0TM99H, BIOS A11 12/08/2016
Workqueue: hci0 hci_power_off
task: ffff9432dad58000 task.stack: ffff986d43790000
RIP: 0010:check_flush_dependency+0xb3/0x100
RSP: 0018:ffff986d43793c90 EFLAGS: 00010086
RAX: 000000000000005a RBX: ffff943316810820 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000096 RDI: 0000000000000001
RBP: ffff986d43793cb0 R08: 0000000000000775 R09: ffffffff85bdd5c0
R10: 0000000000000040 R11: 0000000000000000 R12: ffffffff84d596e0
R13: ffff9432dad58000 R14: ffff94321c640320 R15: ffff9432dad58000
FS: 0000000000000000(0000) GS:ffff94331f500000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007b8bca242000 CR3: 000000014f60a000 CR4: 00000000003406e0
Call Trace:
flush_work+0x8a/0x1c0
? flush_work+0x184/0x1c0
? skb_free_head+0x21/0x30
__cancel_work_timer+0x124/0x1b0
? hci_dev_do_close+0x2a4/0x4d0
cancel_work_sync+0x10/0x20
btusb_close+0x23/0x100
hci_dev_do_close+0x2ca/0x4d0
hci_power_off+0x1e/0x50
process_one_work+0x184/0x3e0
worker_thread+0x4a/0x3a0
? preempt_count_sub+0x9b/0x100
? preempt_count_sub+0x9b/0x100
kthread+0x125/0x140
? process_one_work+0x3e0/0x3e0
? __kthread_create_on_node+0x1a0/0x1a0
? do_syscall_64+0x58/0xd0
ret_from_fork+0x27/0x40
Code: 00 75 bf 49 8b 56 18 48 8d 8b b0 00 00 00 48 81 c6 b0 00 00 00 4d 89 e0 48 c7 c7 20 23 6b 85 c6 05 83 cd 31 01 01 e8 bf c4 0c 00 <0f> ff eb 93 80 3d 74 cd 31 01 00 75 a5 65 48 8b 04 25 00 c5 00
---[ end trace b88fd2f77754bfec ]---
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Reported-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
---
Hello,
Marcel, as this isn't urgent and there is slight chance that this
might trigger another warning if these work items get flushed from a
different MEM_RECLAIM work item from e.g. nfs over network over
bluetooth. Can you please try applying the patch after the 4.13-rc1
closes and see whether it turns up anything else?
Thanks.
net/bluetooth/hci_core.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 05686776a5fb..85ec6f7afbf7 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -3047,15 +3047,14 @@ int hci_register_dev(struct hci_dev *hdev)
BT_DBG("%p name %s bus %d", hdev, hdev->name, hdev->bus);
- hdev->workqueue = alloc_workqueue("%s", WQ_HIGHPRI | WQ_UNBOUND |
- WQ_MEM_RECLAIM, 1, hdev->name);
+ hdev->workqueue = alloc_ordered_workqueue("%s", WQ_HIGHPRI, hdev->name);
if (!hdev->workqueue) {
error = -ENOMEM;
goto err;
}
- hdev->req_workqueue = alloc_workqueue("%s", WQ_HIGHPRI | WQ_UNBOUND |
- WQ_MEM_RECLAIM, 1, hdev->name);
+ hdev->req_workqueue = alloc_ordered_workqueue("%s", WQ_HIGHPRI,
+ hdev->name);
if (!hdev->req_workqueue) {
destroy_workqueue(hdev->workqueue);
error = -ENOMEM;
--
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