From: Hari Vyas <hari.vyas@broadcom.com>
To: bhelgaas@google.com, benh@kernel.crashing.org
Cc: linux-pci@vger.kernel.org, ray.jui@broadcom.com,
Hari Vyas <hari.vyas@broadcom.com>
Subject: [PATCH v3] PCI: Data corruption happening due to race condition
Date: Tue, 3 Jul 2018 14:35:41 +0530 [thread overview]
Message-ID: <1530608741-30664-2-git-send-email-hari.vyas@broadcom.com> (raw)
In-Reply-To: <1530608741-30664-1-git-send-email-hari.vyas@broadcom.com>
When a pci device is detected, a variable is_added is set to
1 in pci device structure and proc, sys entries are created.
When a pci device is removed, first is_added is checked for one
and then device is detached with clearing of proc and sys
entries and at end, is_added is set to 0.
is_added and is_busmaster are bit fields in pci_dev structure
sharing same memory location.
A strange issue was observed with multiple times removal and
rescan of a pcie nvme device using sysfs commands where is_added
flag was observed as zero instead of one while removing device
and proc,sys entries are not cleared. This causes issue in
later device addition with warning message "proc_dir_entry"
already registered.
Debugging revealed a race condition between pcie core driver
enabling is_added bit(pci_bus_add_device()) and nvme driver
reset work-queue enabling is_busmaster bit (by pci_set_master()).
As both fields are not handled in atomic manner and that clears
is_added bit.
Fix moves device addition is_added bit to separate private flag
variable and use different atomic functions to set and retrieve
device addition state. As is_added shares different memory
location so race condition is avoided.
Signed-off-by: Hari Vyas <hari.vyas@broadcom.com>
---
arch/powerpc/kernel/pci-common.c | 4 +++-
arch/powerpc/platforms/powernv/pci-ioda.c | 3 ++-
arch/powerpc/platforms/pseries/setup.c | 3 ++-
drivers/pci/bus.c | 6 +++---
drivers/pci/hotplug/acpiphp_glue.c | 2 +-
drivers/pci/pci.h | 11 +++++++++++
drivers/pci/probe.c | 4 ++--
drivers/pci/remove.c | 5 +++--
include/linux/pci.h | 1 -
9 files changed, 27 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index fe9733f..471aac3 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -42,6 +42,8 @@
#include <asm/ppc-pci.h>
#include <asm/eeh.h>
+#include "../../../drivers/pci/pci.h"
+
/* hose_spinlock protects accesses to the the phb_bitmap. */
static DEFINE_SPINLOCK(hose_spinlock);
LIST_HEAD(hose_list);
@@ -1014,7 +1016,7 @@ void pcibios_setup_bus_devices(struct pci_bus *bus)
/* Cardbus can call us to add new devices to a bus, so ignore
* those who are already fully discovered
*/
- if (dev->is_added)
+ if (pci_dev_is_added(dev))
continue;
pcibios_setup_device(dev);
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 5bd0eb6..70b2e1e 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -46,6 +46,7 @@
#include "powernv.h"
#include "pci.h"
+#include "../../../../drivers/pci/pci.h"
#define PNV_IODA1_M64_NUM 16 /* Number of M64 BARs */
#define PNV_IODA1_M64_SEGS 8 /* Segments per M64 BAR */
@@ -3138,7 +3139,7 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)
struct pci_dn *pdn;
int mul, total_vfs;
- if (!pdev->is_physfn || pdev->is_added)
+ if (!pdev->is_physfn || pci_dev_is_added(pdev))
return;
pdn = pci_get_pdn(pdev);
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 139f0af..8a4868a 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -71,6 +71,7 @@
#include <asm/security_features.h>
#include "pseries.h"
+#include "../../../../drivers/pci/pci.h"
int CMO_PrPSP = -1;
int CMO_SecPSP = -1;
@@ -664,7 +665,7 @@ static void pseries_pci_fixup_iov_resources(struct pci_dev *pdev)
const int *indexes;
struct device_node *dn = pci_device_to_OF_node(pdev);
- if (!pdev->is_physfn || pdev->is_added)
+ if (!pdev->is_physfn || pci_dev_is_added(pdev))
return;
/*Firmware must support open sriov otherwise dont configure*/
indexes = of_get_property(dn, "ibm,open-sriov-vf-bar-info", NULL);
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 35b7fc8..5cb40b2 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -330,7 +330,7 @@ void pci_bus_add_device(struct pci_dev *dev)
return;
}
- dev->is_added = 1;
+ pci_dev_assign_added(dev, true);
}
EXPORT_SYMBOL_GPL(pci_bus_add_device);
@@ -347,14 +347,14 @@ void pci_bus_add_devices(const struct pci_bus *bus)
list_for_each_entry(dev, &bus->devices, bus_list) {
/* Skip already-added devices */
- if (dev->is_added)
+ if (pci_dev_is_added(dev))
continue;
pci_bus_add_device(dev);
}
list_for_each_entry(dev, &bus->devices, bus_list) {
/* Skip if device attach failed */
- if (!dev->is_added)
+ if (!pci_dev_is_added(dev))
continue;
child = dev->subordinate;
if (child)
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 3a17b29..ef0b1b6 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -509,7 +509,7 @@ static void enable_slot(struct acpiphp_slot *slot)
list_for_each_entry(dev, &bus->devices, bus_list) {
/* Assume that newly added devices are powered on already. */
- if (!dev->is_added)
+ if (!pci_dev_is_added(dev))
dev->current_state = PCI_D0;
}
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 882f1f9..0881725 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -288,6 +288,7 @@ struct pci_sriov {
/* pci_dev priv_flags */
#define PCI_DEV_DISCONNECTED 0
+#define PCI_DEV_ADDED 1
static inline int pci_dev_set_disconnected(struct pci_dev *dev, void *unused)
{
@@ -300,6 +301,16 @@ static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
return test_bit(PCI_DEV_DISCONNECTED, &dev->priv_flags);
}
+static inline void pci_dev_assign_added(struct pci_dev *dev, bool added)
+{
+ assign_bit(PCI_DEV_ADDED, &dev->priv_flags, added);
+}
+
+static inline bool pci_dev_is_added(const struct pci_dev *dev)
+{
+ return test_bit(PCI_DEV_ADDED, &dev->priv_flags);
+}
+
#ifdef CONFIG_PCI_ATS
void pci_restore_ats_state(struct pci_dev *dev);
#else
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index ac876e3..611adcd 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2433,13 +2433,13 @@ int pci_scan_slot(struct pci_bus *bus, int devfn)
dev = pci_scan_single_device(bus, devfn);
if (!dev)
return 0;
- if (!dev->is_added)
+ if (!pci_dev_is_added(dev))
nr++;
for (fn = next_fn(bus, dev, 0); fn > 0; fn = next_fn(bus, dev, fn)) {
dev = pci_scan_single_device(bus, devfn + fn);
if (dev) {
- if (!dev->is_added)
+ if (!pci_dev_is_added(dev))
nr++;
dev->multifunction = 1;
}
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 6f072ea..5e3d0dc 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -19,11 +19,12 @@ static void pci_stop_dev(struct pci_dev *dev)
{
pci_pme_active(dev, false);
- if (dev->is_added) {
+ if (pci_dev_is_added(dev)) {
device_release_driver(&dev->dev);
pci_proc_detach_device(dev);
pci_remove_sysfs_dev_files(dev);
- dev->is_added = 0;
+
+ pci_dev_assign_added(dev, false);
}
if (dev->bus->self)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 340029b..506125b 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -368,7 +368,6 @@ struct pci_dev {
unsigned int transparent:1; /* Subtractive decode bridge */
unsigned int multifunction:1; /* Multi-function device */
- unsigned int is_added:1;
unsigned int is_busmaster:1; /* Is busmaster */
unsigned int no_msi:1; /* May not use MSI */
unsigned int no_64bit_msi:1; /* May only use 32-bit MSIs */
--
1.9.1
next prev parent reply other threads:[~2018-07-03 9:05 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-03 9:05 [PATCH v3] PCI: Data corruption happening due to race condition Hari Vyas
2018-07-03 9:05 ` Hari Vyas [this message]
2018-07-03 9:13 ` Lukas Wunner
2018-07-18 23:29 ` Bjorn Helgaas
2018-07-19 4:18 ` Benjamin Herrenschmidt
2018-07-19 14:04 ` Hari Vyas
2018-07-19 18:55 ` Lukas Wunner
2018-07-20 4:27 ` Benjamin Herrenschmidt
2018-07-27 22:25 ` Bjorn Helgaas
2018-07-28 0:45 ` Benjamin Herrenschmidt
2018-07-31 11:21 ` Michael Ellerman
2018-07-19 17:41 ` Bjorn Helgaas
2018-07-20 9:16 ` Hari Vyas
2018-07-20 12:20 ` Bjorn Helgaas
2018-07-31 16:37 ` Bjorn Helgaas
2018-08-15 3:35 ` PCIe enable device races (Was: [PATCH v3] PCI: Data corruption happening due to race condition) Benjamin Herrenschmidt
2018-08-15 4:16 ` Benjamin Herrenschmidt
2018-08-15 4:44 ` Benjamin Herrenschmidt
2018-08-15 5:21 ` [RFC PATCH] pci: Proof of concept at fixing pci_enable_device/bridge races Benjamin Herrenschmidt
2018-08-15 19:09 ` PCIe enable device races (Was: [PATCH v3] PCI: Data corruption happening due to race condition) Bjorn Helgaas
2018-08-15 21:50 ` [RFC PATCH] pci: Proof of concept at fixing pci_enable_device/bridge races Benjamin Herrenschmidt
2018-08-15 22:40 ` Guenter Roeck
2018-08-15 23:38 ` Benjamin Herrenschmidt
2018-08-20 1:31 ` Guenter Roeck
2018-08-17 3:07 ` Bjorn Helgaas
2018-08-17 3:42 ` Benjamin Herrenschmidt
2018-08-15 18:50 ` PCIe enable device races (Was: [PATCH v3] PCI: Data corruption happening due to race condition) Bjorn Helgaas
2018-08-15 21:52 ` Benjamin Herrenschmidt
2018-08-15 23:23 ` Benjamin Herrenschmidt
2018-08-16 7:58 ` Konstantin Khlebnikov
2018-08-16 8:02 ` Benjamin Herrenschmidt
2018-08-16 9:22 ` Hari Vyas
2018-08-16 10:10 ` Benjamin Herrenschmidt
2018-08-16 10:11 ` Benjamin Herrenschmidt
2018-08-16 10:26 ` Lukas Wunner
2018-08-16 10:47 ` Hari Vyas
2018-08-16 23:20 ` Benjamin Herrenschmidt
2018-08-16 23:17 ` Benjamin Herrenschmidt
2018-08-17 0:43 ` Benjamin Herrenschmidt
2018-08-16 19:43 ` Jens Axboe
2018-08-16 21:37 ` Benjamin Herrenschmidt
2018-08-16 21:56 ` Jens Axboe
2018-08-16 23:09 ` Benjamin Herrenschmidt
2018-08-17 0:14 ` Jens Axboe
2018-08-16 12:28 ` Lukas Wunner
2018-08-16 23:25 ` Benjamin Herrenschmidt
2018-08-17 1:12 ` Benjamin Herrenschmidt
2018-08-17 16:39 ` Lukas Wunner
2018-08-18 3:37 ` Benjamin Herrenschmidt
2018-08-18 9:22 ` Lukas Wunner
2018-08-18 13:11 ` Benjamin Herrenschmidt
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