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From: Greg KH <gregkh@suse.de>
To: linux-kernel@vger.kernel.org, stable@kernel.org
Cc: Justin Forbes <jmforbes@linuxtx.org>,
	Zwane Mwaikambo <zwane@arm.linux.org.uk>,
	"Theodore Ts'o" <tytso@mit.edu>,
	Randy Dunlap <rdunlap@xenotime.net>,
	Dave Jones <davej@redhat.com>,
	Chuck Wolber <chuckw@quantumlinux.com>,
	Chris Wedgwood <reviews@ml.cw.f00f.org>,
	Michael Krufky <mkrufky@linuxtv.org>,
	Chuck Ebbert <cebbert@redhat.com>,
	Domenico Andreoli <cavokz@gmail.com>,
	torvalds@linux-foundation.org, akpm@linux-foundation.org,
	alan@lxorguk.ukuu.org.uk, linux-pci@atrey.karlin.mff.cuni.cz,
	Ian Abbott <abbotti@mev.co.uk>
Subject: [patch 73/73] PCI: Fix fakephp deadlock
Date: Wed, 6 Feb 2008 15:54:43 -0800	[thread overview]
Message-ID: <20080206235443.GV13121@suse.de> (raw)
In-Reply-To: <20080206235015.GA13121@suse.de>

[-- Attachment #1: pci-fix-fakephp-deadlock.patch --]
[-- Type: text/plain, Size: 4092 bytes --]


2.6.23-stable review patch.  If anyone has any objections, please let us know.
------------------
From: Ian Abbott <abbotti@mev.co.uk>

This patch works around a problem in the fakephp driver when a process
writing "0" to a "power" sysfs file to fake removal of a PCI device ends
up deadlocking itself in the sysfs code.

The patch is functionally identical to the one in Linus' tree post 2.6.24:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=5c796ae7a7ebe56967ed9b9963d7c16d733635ff

I have tested it on a 2.6.23 kernel.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/pci/hotplug/fakephp.c |   39 +++++++++++++++++++++++++++++++++++----
 1 file changed, 35 insertions(+), 4 deletions(-)

--- a/drivers/pci/hotplug/fakephp.c
+++ b/drivers/pci/hotplug/fakephp.c
@@ -39,6 +39,7 @@
 #include <linux/init.h>
 #include <linux/string.h>
 #include <linux/slab.h>
+#include <linux/workqueue.h>
 #include "../pci.h"
 
 #if !defined(MODULE)
@@ -63,10 +64,16 @@ struct dummy_slot {
 	struct list_head node;
 	struct hotplug_slot *slot;
 	struct pci_dev *dev;
+	struct work_struct remove_work;
+	unsigned long removed;
 };
 
 static int debug;
 static LIST_HEAD(slot_list);
+static struct workqueue_struct *dummyphp_wq;
+
+static void pci_rescan_worker(struct work_struct *work);
+static DECLARE_WORK(pci_rescan_work, pci_rescan_worker);
 
 static int enable_slot (struct hotplug_slot *slot);
 static int disable_slot (struct hotplug_slot *slot);
@@ -109,7 +116,7 @@ static int add_slot(struct pci_dev *dev)
 	slot->name = &dev->dev.bus_id[0];
 	dbg("slot->name = %s\n", slot->name);
 
-	dslot = kmalloc(sizeof(struct dummy_slot), GFP_KERNEL);
+	dslot = kzalloc(sizeof(struct dummy_slot), GFP_KERNEL);
 	if (!dslot)
 		goto error_info;
 
@@ -164,6 +171,14 @@ static void remove_slot(struct dummy_slo
 		err("Problem unregistering a slot %s\n", dslot->slot->name);
 }
 
+/* called from the single-threaded workqueue handler to remove a slot */
+static void remove_slot_worker(struct work_struct *work)
+{
+	struct dummy_slot *dslot =
+		container_of(work, struct dummy_slot, remove_work);
+	remove_slot(dslot);
+}
+
 /**
  * Rescan slot.
  * Tries hard not to re-enable already existing devices
@@ -267,11 +282,17 @@ static inline void pci_rescan(void) {
 	pci_rescan_buses(&pci_root_buses);
 }
 
+/* called from the single-threaded workqueue handler to rescan all pci buses */
+static void pci_rescan_worker(struct work_struct *work)
+{
+	pci_rescan();
+}
 
 static int enable_slot(struct hotplug_slot *hotplug_slot)
 {
 	/* mis-use enable_slot for rescanning of the pci bus */
-	pci_rescan();
+	cancel_work_sync(&pci_rescan_work);
+	queue_work(dummyphp_wq, &pci_rescan_work);
 	return -ENODEV;
 }
 
@@ -306,6 +327,10 @@ static int disable_slot(struct hotplug_s
 		err("Can't remove PCI devices with other PCI devices behind it yet.\n");
 		return -ENODEV;
 	}
+	if (test_and_set_bit(0, &dslot->removed)) {
+		dbg("Slot already scheduled for removal\n");
+		return -ENODEV;
+	}
 	/* search for subfunctions and disable them first */
 	if (!(dslot->dev->devfn & 7)) {
 		for (func = 1; func < 8; func++) {
@@ -328,8 +353,9 @@ static int disable_slot(struct hotplug_s
 	/* remove the device from the pci core */
 	pci_remove_bus_device(dslot->dev);
 
-	/* blow away this sysfs entry and other parts. */
-	remove_slot(dslot);
+	/* queue work item to blow away this sysfs entry and other parts. */
+	INIT_WORK(&dslot->remove_work, remove_slot_worker);
+	queue_work(dummyphp_wq, &dslot->remove_work);
 
 	return 0;
 }
@@ -340,6 +366,7 @@ static void cleanup_slots (void)
 	struct list_head *next;
 	struct dummy_slot *dslot;
 
+	destroy_workqueue(dummyphp_wq);
 	list_for_each_safe (tmp, next, &slot_list) {
 		dslot = list_entry (tmp, struct dummy_slot, node);
 		remove_slot(dslot);
@@ -351,6 +378,10 @@ static int __init dummyphp_init(void)
 {
 	info(DRIVER_DESC "\n");
 
+	dummyphp_wq = create_singlethread_workqueue(MY_NAME);
+	if (!dummyphp_wq)
+		return -ENOMEM;
+
 	return pci_scan_buses();
 }
 

-- 

  parent reply	other threads:[~2008-02-07  0:33 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20080206234302.769849277@mini.kroah.org>
2008-02-06 23:50 ` [patch 00/73] 2.6.23-stable review Greg KH
2008-02-06 23:50   ` [patch 01/73] SPARC64: Fix sparc64 cpu cross call hangs Greg KH
2008-02-06 23:50   ` [patch 02/73] dm: table detect io beyond device Greg KH
2008-02-06 23:50   ` [patch 03/73] dm crypt: fix write endio Greg KH
2008-02-06 23:50   ` [patch 04/73] dm crypt: use bio_add_page Greg KH
2008-02-06 23:51   ` [patch 05/73] ACPI: video_device_list corruption Greg KH
2008-02-06 23:51   ` [patch 06/73] ACPI: thinkpad-acpi: fix lenovo keymap for brightness Greg KH
2008-02-06 23:51   ` [patch 07/73] SPARC64: Fix memory controller register access when non-SMP Greg KH
2008-02-06 23:51   ` [patch 08/73] SPARC64: Fix two kernel linear mapping setup bugs Greg KH
2008-02-06 23:51   ` [patch 09/73] IPSEC: Fix potential dst leak in xfrm_lookup Greg KH
2008-02-06 23:51   ` [patch 10/73] VLAN: Lost rtnl_unlock() in vlan_ioctl() Greg KH
2008-02-06 23:51   ` [patch 11/73] tty: fix logic change introduced by wait_event_interruptible_timeout() Greg KH
2008-02-06 23:51   ` [patch 12/73] IPV4 raw: Strengthen check on validity of iph->ihl Greg KH
2008-02-06 23:51   ` [patch 13/73] sky2: disable rx checksum on Yukon XL Greg KH
2008-02-06 23:51   ` [patch 14/73] sky2: RX lockup fix Greg KH
2008-02-06 23:51   ` [patch 15/73] POWERPC: Change fallocate to match unistd.h on powerpc Greg KH
2008-02-06 23:51   ` [patch 16/73] X25: Add missing x25_neigh_put Greg KH
2008-02-06 23:51   ` [patch 17/73] NET: mcs7830 passes msecs instead of jiffies to usb_control_msg Greg KH
2008-02-06 23:51   ` [patch 18/73] NET: kaweth was forgotten in msec switchover of usb_start_wait_urb Greg KH
2008-02-06 23:51   ` [patch 19/73] IRDA: irda_create() nuke user triggable printk Greg KH
2008-02-06 23:51   ` [patch 20/73] INET: Fix netdev renaming and inet address labels Greg KH
2008-02-06 23:52   ` [patch 21/73] CONNECTOR: Dont touch queue dev after decrement of ref count Greg KH
2008-02-06 23:52   ` [patch 22/73] ATM: Check IP header validity in mpc_send_packet Greg KH
2008-02-06 23:52   ` [patch 23/73] IPV4 ROUTE: ip_rt_dump() is unecessary slow Greg KH
2008-02-06 23:52   ` [patch 24/73] ATM: delay irq setup until card is configured Greg KH
2008-02-06 23:52   ` [patch 25/73] IPSEC: Avoid undefined shift operation when testing algorithm ID Greg KH
2008-02-06 23:52   ` [patch 26/73] NET: Correct two mistaken skb_reset_mac_header() conversions Greg KH
2008-02-06 23:52   ` [patch 27/73] IPV4: ip_gre: set mac_header correctly in receive path Greg KH
2008-02-06 23:52   ` [patch 28/73] CASSINI: Fix endianness bug Greg KH
2008-02-06 23:52   ` [patch 29/73] CASSINI: Revert dont touch page_count Greg KH
2008-02-06 23:52   ` [patch 30/73] CASSINI: Set skb->truesize properly on receive packets Greg KH
2008-02-06 23:52   ` [patch 31/73] SPARC64: Fix OOPS in dma_sync_*_for_device() Greg KH
2008-02-06 23:52   ` [patch 32/73] SPARC64: Implement pci_resource_to_user() Greg KH
2008-02-06 23:52   ` [patch 33/73] ACPICA: fix acpi-cpufreq boot crash due to _PSD return-by-reference Greg KH
2008-02-06 23:52   ` [patch 34/73] ACPI: Not register gsi for PCI IDE controller in legacy mode Greg KH
2008-02-06 23:52   ` [patch 35/73] ACPICA: fix acpi_serialize hang regression Greg KH
2008-02-06 23:53   ` [patch 36/73] ACPI: apply quirk_ich6_lpc_acpi to more ICH8 and ICH9 Greg KH
2008-02-06 23:53   ` [patch 37/73] PM: ACPI and APM must not be enabled at the same time Greg KH
2008-02-06 23:53   ` [patch 38/73] CRYPTO: padlock: Fix spurious ECB page fault Greg KH
2008-02-06 23:53   ` [patch 39/73] USB: update sierra.c with latest device ids that are in 2.6.24-rc7 Greg KH
2008-02-06 23:53   ` [patch 40/73] clockevents: fix reprogramming decision in oneshot broadcast Greg KH
2008-02-06 23:53   ` [patch 41/73] Freezer: Fix APM emulation breakage Greg KH
2008-02-06 23:53   ` [patch 42/73] vfs: coredumping fix (CVE-2007-6206) Greg KH
2008-02-06 23:53   ` [patch 43/73] quicklists: do not release off node pages early Greg KH
2008-02-06 23:53   ` [patch 44/73] quicklists: Only consider memory that can be used with GFP_KERNEL Greg KH
2008-02-06 23:53   ` [patch 45/73] chelsio: Fix skb->dev setting Greg KH
2008-02-06 23:53   ` [patch 46/73] cxgb: fix T2 GSO Greg KH
2008-02-06 23:53   ` [patch 47/73] cxgb: fix stats Greg KH
2008-02-06 23:53   ` [patch 48/73] Input: implement proper locking in input core Greg KH
2008-02-06 23:53   ` [patch 49/73] Input: evdev - implement proper locking Greg KH
2008-02-06 23:53   ` [patch 50/73] Input: mousedev " Greg KH
2008-02-06 23:53   ` [patch 51/73] Input: joydev " Greg KH
2008-02-06 23:53   ` [patch 52/73] Input: tsdev " Greg KH
2008-02-06 23:53   ` [patch 53/73] Input: fix open count handling in input interfaces Greg KH
2008-02-06 23:53   ` [patch 54/73] CIFS: Respect umask when using POSIX mkdir Greg KH
2008-02-06 23:53   ` [patch 55/73] m68k: Export cachectl.h Greg KH
2008-02-06 23:53   ` [patch 56/73] VM/Security: add security hook to do_brk (CVE-2007-6434) Greg KH
2008-02-06 23:54   ` [patch 57/73] security: protect from stack expantion into low vm addresses Greg KH
2008-02-06 23:54   ` [patch 58/73] md: fix data corruption when a degraded raid5 array is reshaped Greg KH
2008-02-06 23:54   ` [patch 59/73] knfsd: Allow NFSv2/3 WRITE calls to succeed when krb5i etc is used Greg KH
2008-02-06 23:54   ` [patch 60/73] vm audit: add VM_DONTEXPAND to mmap for drivers that need it (CVE-2008-0007) Greg KH
2008-02-06 23:54   ` [patch 61/73] sata_promise: ASIC PRD table bug workaround Greg KH
2008-02-06 23:54   ` [patch 62/73] ia64: Fix unaligned handler for floating point instructions with base update Greg KH
2008-02-06 23:54   ` [patch 63/73] Fix unbalanced helper_lock in kernel/kmod.c Greg KH
2008-02-06 23:54   ` [patch 64/73] spi: omap2_mcspi PIO RX fix Greg KH
2008-02-06 23:54   ` [patch 65/73] libata: port and host should be stopped before hardware resources are released Greg KH
2008-02-06 23:54   ` [patch 66/73] fix oops on rmmod capidrv Greg KH
2008-02-06 23:54   ` [patch 67/73] Netfilter: bridge: fix double POST_ROUTING invocation Greg KH
2008-02-06 23:54   ` [patch 68/73] Netfilter: bridge-netfilter: fix net_device refcnt leaks Greg KH
2008-02-06 23:54   ` [patch 69/73] Fix dirty page accounting leak with ext3 data=journal Greg KH
2008-02-06 23:54   ` [patch 70/73] forcedeth: mac address mcp77/79 Greg KH
2008-02-06 23:54   ` [patch 71/73] atl1: fix frame length bug Greg KH
2008-02-06 23:54   ` [patch 72/73] ACPI: sync blacklist w/ latest Greg KH
2008-02-06 23:54   ` Greg KH [this message]
2008-02-08  5:31   ` [stable] [patch 00/73] 2.6.23-stable review Greg KH

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