From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Juergen Gross <jgross@suse.com>,
David Woodhouse <dwmw@amazon.co.uk>,
Salvatore Bonaccorso <carnil@debian.org>,
Jason Andryuk <jandryuk@gmail.com>
Subject: [PATCH 4.14 10/30] xen: Fix XenStore initialisation for XS_LOCAL
Date: Tue, 2 Feb 2021 14:38:51 +0100 [thread overview]
Message-ID: <20210202132942.559697405@linuxfoundation.org> (raw)
In-Reply-To: <20210202132942.138623851@linuxfoundation.org>
From: David Woodhouse <dwmw@amazon.co.uk>
commit 5f46400f7a6a4fad635d5a79e2aa5a04a30ffea1 upstream.
In commit 3499ba8198ca ("xen: Fix event channel callback via INTX/GSI")
I reworked the triggering of xenbus_probe().
I tried to simplify things by taking out the workqueue based startup
triggered from wake_waiting(); the somewhat poorly named xenbus IRQ
handler.
I missed the fact that in the XS_LOCAL case (Dom0 starting its own
xenstored or xenstore-stubdom, which happens after the kernel is booted
completely), that IRQ-based trigger is still actually needed.
So... put it back, except more cleanly. By just spawning a xenbus_probe
thread which waits on xb_waitq and runs the probe the first time it
gets woken, just as the workqueue-based hack did.
This is actually a nicer approach for *all* the back ends with different
interrupt methods, and we can switch them all over to that without the
complex conditions for when to trigger it. But not in -rc6. This is
the minimal fix for the regression, although it's a step in the right
direction instead of doing a partial revert and actually putting the
workqueue back. It's also simpler than the workqueue.
Fixes: 3499ba8198ca ("xen: Fix event channel callback via INTX/GSI")
Reported-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/4c9af052a6e0f6485d1de43f2c38b1461996db99.camel@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Cc: Salvatore Bonaccorso <carnil@debian.org>
Cc: Jason Andryuk <jandryuk@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/xen/xenbus/xenbus_probe.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -705,6 +705,23 @@ static bool xs_hvm_defer_init_for_callba
#endif
}
+static int xenbus_probe_thread(void *unused)
+{
+ DEFINE_WAIT(w);
+
+ /*
+ * We actually just want to wait for *any* trigger of xb_waitq,
+ * and run xenbus_probe() the moment it occurs.
+ */
+ prepare_to_wait(&xb_waitq, &w, TASK_INTERRUPTIBLE);
+ schedule();
+ finish_wait(&xb_waitq, &w);
+
+ DPRINTK("probing");
+ xenbus_probe();
+ return 0;
+}
+
static int __init xenbus_probe_initcall(void)
{
/*
@@ -716,6 +733,20 @@ static int __init xenbus_probe_initcall(
!xs_hvm_defer_init_for_callback()))
xenbus_probe();
+ /*
+ * For XS_LOCAL, spawn a thread which will wait for xenstored
+ * or a xenstore-stubdom to be started, then probe. It will be
+ * triggered when communication starts happening, by waiting
+ * on xb_waitq.
+ */
+ if (xen_store_domain_type == XS_LOCAL) {
+ struct task_struct *probe_task;
+
+ probe_task = kthread_run(xenbus_probe_thread, NULL,
+ "xenbus_probe");
+ if (IS_ERR(probe_task))
+ return PTR_ERR(probe_task);
+ }
return 0;
}
device_initcall(xenbus_probe_initcall);
next prev parent reply other threads:[~2021-02-02 14:52 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-02 13:38 [PATCH 4.14 00/30] 4.14.219-rc1 review Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 01/30] nbd: freeze the queue while were adding connections Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 02/30] ACPI: sysfs: Prefer "compatible" modalias Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 03/30] ARM: dts: imx6qdl-gw52xx: fix duplicate regulator naming Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 04/30] wext: fix NULL-ptr-dereference with cfg80211s lack of commit() Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 05/30] net: usb: qmi_wwan: added support for Thales Cinterion PLSx3 modem family Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 06/30] drivers: soc: atmel: Avoid calling at91_soc_init on non AT91 SoCs Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 07/30] drivers: soc: atmel: add null entry at the end of at91_soc_allowed_list[] Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 08/30] KVM: x86/pmu: Fix HW_REF_CPU_CYCLES event pseudo-encoding in intel_arch_events[] Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 09/30] KVM: x86: get smi pending status correctly Greg Kroah-Hartman
2021-02-02 13:38 ` Greg Kroah-Hartman [this message]
2021-02-02 13:38 ` [PATCH 4.14 11/30] leds: trigger: fix potential deadlock with libata Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 12/30] mt7601u: fix kernel crash unplugging the device Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 13/30] mt7601u: fix rx buffer refcounting Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 14/30] xen-blkfront: allow discard-* nodes to be optional Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 15/30] ARM: imx: build suspend-imx6.S with arm instruction set Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 16/30] netfilter: nft_dynset: add timeout extension to template Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 17/30] xfrm: Fix oops in xfrm_replay_advance_bmp Greg Kroah-Hartman
2021-02-02 13:38 ` [PATCH 4.14 18/30] RDMA/cxgb4: Fix the reported max_recv_sge value Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 19/30] iwlwifi: pcie: use jiffies for memory read spin time limit Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 20/30] iwlwifi: pcie: reschedule in long-running memory reads Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 21/30] mac80211: pause TX while changing interface type Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 22/30] can: dev: prevent potential information leak in can_fill_info() Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 23/30] x86/entry/64/compat: Preserve r8-r11 in int $0x80 Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 24/30] x86/entry/64/compat: Fix "x86/entry/64/compat: Preserve r8-r11 in int $0x80" Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 25/30] iommu/vt-d: Gracefully handle DMAR units with no supported address widths Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 26/30] iommu/vt-d: Dont dereference iommu_device if IOMMU_API is not built Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 27/30] NFC: fix resource leak when target index is invalid Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 28/30] NFC: fix possible resource leak Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 29/30] team: protect features update by RCU to avoid deadlock Greg Kroah-Hartman
2021-02-02 13:39 ` [PATCH 4.14 30/30] tcp: fix TLP timer not set when CA_STATE changes from DISORDER to OPEN Greg Kroah-Hartman
2021-02-03 9:42 ` [PATCH 4.14 00/30] 4.14.219-rc1 review Naresh Kamboju
2021-02-03 20:41 ` Guenter Roeck
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