From 72978b2fe2f2cdf9f319c6c6dcdbe92b38de2be2 Mon Sep 17 00:00:00 2001 From: Ross Lagerwall Date: Mon, 19 Jan 2015 13:19:38 +0000 Subject: [PATCH] xen/manage: Fix USB interaction issues when resuming Commit 61a734d305e1 ("xen/manage: Always freeze/thaw processes when suspend/resuming") ensured that userspace processes were always frozen before suspending to reduce interaction issues when resuming devices. However, freeze_processes() does not freeze kernel threads. Freeze kernel threads as well to prevent deadlocks with the khubd thread when resuming devices. This is what native suspend and resume does. Example deadlock: [ 7279.648010] [] ? xen_poll_irq_timeout+0x3e/0x50 [ 7279.648010] [] xen_poll_irq+0x10/0x20 [ 7279.648010] [] xen_lock_spinning+0xb3/0x120 [ 7279.648010] [] __raw_callee_save_xen_lock_spinning+0x11/0x20 [ 7279.648010] [] ? usb_control_msg+0xe6/0x120 [ 7279.648010] [] ? _raw_spin_lock_irq+0x50/0x60 [ 7279.648010] [] wait_for_completion+0xac/0x160 [ 7279.648010] [] ? try_to_wake_up+0x2c0/0x2c0 [ 7279.648010] [] dpm_wait+0x32/0x40 [ 7279.648010] [] device_resume+0x90/0x210 [ 7279.648010] [] dpm_resume+0x121/0x250 [ 7279.648010] [] ? xenbus_dev_request_and_reply+0xc0/0xc0 [ 7279.648010] [] dpm_resume_end+0x15/0x30 [ 7279.648010] [] do_suspend+0x10a/0x200 [ 7279.648010] [] ? xen_pre_suspend+0x20/0x20 [ 7279.648010] [] shutdown_handler+0x120/0x150 [ 7279.648010] [] xenwatch_thread+0x9f/0x160 [ 7279.648010] [] ? finish_wait+0x80/0x80 [ 7279.648010] [] kthread+0xc9/0xe0 [ 7279.648010] [] ? flush_kthread_worker+0x80/0x80 [ 7279.648010] [] ret_from_fork+0x7c/0xb0 [ 7279.648010] [] ? flush_kthread_worker+0x80/0x80 [ 7441.216287] INFO: task khubd:89 blocked for more than 120 seconds. [ 7441.219457] Tainted: G X 3.13.11-ckt12.kz #1 [ 7441.222176] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 7441.225827] khubd D ffff88003f433440 0 89 2 0x00000000 [ 7441.229258] ffff88003ceb9b98 0000000000000046 ffff88003ce83000 0000000000013440 [ 7441.232959] ffff88003ceb9fd8 0000000000013440 ffff88003cd13000 ffff88003ce83000 [ 7441.236658] 0000000000000286 ffff88003d3e0000 ffff88003ceb9bd0 00000001001aa01e [ 7441.240415] Call Trace: [ 7441.241614] [] schedule+0x29/0x70 [ 7441.243930] [] schedule_timeout+0x166/0x2c0 [ 7441.246681] [] ? call_timer_fn+0x110/0x110 [ 7441.249339] [] schedule_timeout_uninterruptible+0x1e/0x20 [ 7441.252644] [] msleep+0x20/0x30 [ 7441.254812] [] hub_port_reset+0xf0/0x580 [ 7441.257400] [] hub_port_init+0x75/0xb40 [ 7441.259981] [] ? update_autosuspend+0x39/0x60 [ 7441.262817] [] ? pm_runtime_set_autosuspend_delay+0x50/0xa0 [ 7441.266212] [] hub_thread+0x71a/0x1750 [ 7441.268728] [] ? finish_wait+0x80/0x80 [ 7441.271272] [] ? usb_port_resume+0x670/0x670 [ 7441.274067] [] kthread+0xc9/0xe0 [ 7441.276305] [] ? flush_kthread_worker+0x80/0x80 [ 7441.279131] [] ret_from_fork+0x7c/0xb0 [ 7441.281659] [] ? flush_kthread_worker+0x80/0x80 Signed-off-by: Ross Lagerwall Cc: stable@vger.kernel.org Signed-off-by: David Vrabel --- drivers/xen/manage.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c index f8bb36f9d9ce..bf1940706422 100644 --- a/drivers/xen/manage.c +++ b/drivers/xen/manage.c @@ -105,10 +105,16 @@ static void do_suspend(void) err = freeze_processes(); if (err) { - pr_err("%s: freeze failed %d\n", __func__, err); + pr_err("%s: freeze processes failed %d\n", __func__, err); goto out; } + err = freeze_kernel_threads(); + if (err) { + pr_err("%s: freeze kernel threads failed %d\n", __func__, err); + goto out_thaw; + } + err = dpm_suspend_start(PMSG_FREEZE); if (err) { pr_err("%s: dpm_suspend_start %d\n", __func__, err);