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From: Chris Wright <chrisw@sous-sol.org>
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>,
	torvalds@linux-foundation.org, akpm@linux-foundation.org,
	alan@lxorguk.ukuu.org.uk, Kirill Korotaev <dev@openvz.org>,
	Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@osdl.org>,
	Linus Torvalds <torvalds@osdl.org>
Subject: [patch 58/59] move_task_off_dead_cpu() should be called with disabled ints
Date: Fri, 02 Feb 2007 18:36:02 -0800	[thread overview]
Message-ID: <20070203024730.601627000@sous-sol.org> (raw)
In-Reply-To: <20070203023504.435051000@sous-sol.org>

[-- Attachment #1: move_task_off_dead_cpu-should-be-called-with-disabled-ints.patch --]
[-- Type: text/plain, Size: 2474 bytes --]

-stable review patch.  If anyone has any objections, please let us know.
------------------

From: Kirill Korotaev <dev@openvz.org>

move_task_off_dead_cpu() requires interrupts to be disabled, while
migrate_dead() calls it with enabled interrupts.  Added appropriate
comments to functions and added BUG_ON(!irqs_disabled()) into
double_rq_lock() and double_lock_balance() which are the origin sources of
such bugs.

Signed-off-by: Kirill Korotaev <dev@openvz.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
 kernel/sched.c |   17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

--- linux-2.6.19.2.orig/kernel/sched.c
+++ linux-2.6.19.2/kernel/sched.c
@@ -1941,6 +1941,7 @@ static void double_rq_lock(struct rq *rq
 	__acquires(rq1->lock)
 	__acquires(rq2->lock)
 {
+	BUG_ON(!irqs_disabled());
 	if (rq1 == rq2) {
 		spin_lock(&rq1->lock);
 		__acquire(rq2->lock);	/* Fake it out ;) */
@@ -1980,6 +1981,11 @@ static void double_lock_balance(struct r
 	__acquires(busiest->lock)
 	__acquires(this_rq->lock)
 {
+	if (unlikely(!irqs_disabled())) {
+		/* printk() doesn't work good under rq->lock */
+		spin_unlock(&this_rq->lock);
+		BUG_ON(1);
+	}
 	if (unlikely(!spin_trylock(&busiest->lock))) {
 		if (busiest < this_rq) {
 			spin_unlock(&this_rq->lock);
@@ -5050,7 +5056,10 @@ wait_to_die:
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-/* Figure out where task on dead CPU should go, use force if neccessary. */
+/*
+ * Figure out where task on dead CPU should go, use force if neccessary.
+ * NOTE: interrupts should be disabled by the caller
+ */
 static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
 {
 	unsigned long flags;
@@ -5170,6 +5179,7 @@ void idle_task_exit(void)
 	mmdrop(mm);
 }
 
+/* called under rq->lock with disabled interrupts */
 static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
 {
 	struct rq *rq = cpu_rq(dead_cpu);
@@ -5186,10 +5196,11 @@ static void migrate_dead(unsigned int de
 	 * Drop lock around migration; if someone else moves it,
 	 * that's OK.  No task can be added to this CPU, so iteration is
 	 * fine.
+	 * NOTE: interrupts should be left disabled  --dev@
 	 */
-	spin_unlock_irq(&rq->lock);
+	spin_unlock(&rq->lock);
 	move_task_off_dead_cpu(dead_cpu, p);
-	spin_lock_irq(&rq->lock);
+	spin_lock(&rq->lock);
 
 	put_task_struct(p);
 }

--

  parent reply	other threads:[~2007-02-03  2:46 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-03  2:35 [patch 00/59] -stable review Chris Wright
2007-02-03  2:35 ` [patch 01/59] i2c-mv64xxx: Fix random oops at boot Chris Wright
2007-02-03  2:35 ` [patch 02/59] i2c/m41t00: Do not forget to write year Chris Wright
2007-02-03  2:35 ` [patch 03/59] Check for populated zone in __drain_pages Chris Wright
2007-02-03  2:35 ` [patch 04/59] Fix HWRNG built-in initcalls priority Chris Wright
2007-02-03  2:35 ` [patch 05/59] md: pass down BIO_RW_SYNC in raid{1,10} Chris Wright
2007-02-03  2:35 ` [patch 06/59] NETFILTER: Fix routing of REJECT target generated packets in output chain Chris Wright
2007-02-03  2:35 ` [patch 07/59] NETFILTER: nf_conntrack_ipv6: fix crash when handling fragments Chris Wright
2007-02-03  2:35 ` [patch 08/59] NETFILTER: tcp conntrack: fix IP_CT_TCP_FLAG_CLOSE_INIT value Chris Wright
2007-02-03  2:35 ` [patch 09/59] NETFILTER: arp_tables: fix userspace compilation Chris Wright
2007-02-03  2:35 ` [patch 10/59] Repair snd-usb-usx2y over OHCI Chris Wright
2007-02-03  2:35 ` [patch 11/59] [stable] [PATCH] IB/mthca: Fix off-by-one in FMR handling on memfree Chris Wright
2007-02-03  2:35 ` [patch 12/59] [PATCH] Fix reparenting to the same thread group. (take 2) Chris Wright
2007-02-03  2:35 ` [patch 13/59] ieee1394: sbp2: fix probing of some DVD-ROM/RWs Chris Wright
2007-02-03  2:35 ` [patch 14/59] sched: tasks cannot run on cpus onlined after boot Chris Wright
2007-02-03  2:35 ` [patch 15/59] Fix up CIFS for "test_clear_page_dirty()" removal Chris Wright
2007-02-03  2:35 ` [patch 16/59] start_kernel: test if irqs got enabled early, barf, and disable them again Chris Wright
2007-02-03  2:35 ` [patch 17/59] PCI: prevent down_read when pci_devices is empty Chris Wright
2007-02-03 16:16   ` Kumar Gala
2007-02-05 17:04     ` Chris Wright
2007-02-03  2:35 ` [patch 18/59] IPV6 MCAST: Fix joining all-node multicast group on device initialization Chris Wright
2007-02-03  2:35 ` [patch 19/59] NETFILTER: ctnetlink: check for status attribute existence on conntrack creation Chris Wright
2007-02-03  2:35 ` [patch 20/59] NETFILTER: ctnetlink: fix leak in ctnetlink_create_conntrack error path Chris Wright
2007-02-03  2:35 ` [patch 21/59] IPSEC: Policy list disorder Chris Wright
2007-02-03  2:35 ` [patch 22/59] ALSA hda-codec - Fix NULL dereference in generic hda code Chris Wright
2007-02-03  2:35 ` [patch 23/59] SELinux: fix an oops with NetLabel and non-MLS SELinux policy Chris Wright
2007-02-03  2:35 ` [patch 24/59] IB/iser: return error code when PDUs may not be sent Chris Wright
2007-02-03  2:35 ` [patch 25/59] Fix UML on non-standard VM split hosts Chris Wright
2007-02-04  1:06   ` Randy Dunlap
2007-02-04  3:11     ` Jeff Dike
2007-02-04  4:19       ` Randy Dunlap
2007-02-03  2:35 ` [patch 26/59] ACPI: fix cpufreq regression Chris Wright
2007-02-03  2:35 ` [patch 27/59] x86: Work around gcc 4.2 over aggressive optimizer Chris Wright
2007-02-03  2:35 ` [patch 28/59] NETFILTER: Fix iptables ABI breakage on (at least) CRIS Chris Wright
2007-02-03  2:35 ` [patch 29/59] elevator: move clearing of unplug flag earlier Chris Wright
2007-02-03  2:35 ` [patch 30/59] Revert "[PATCH] Fix up mmap_kmem" Chris Wright
2007-02-03  2:35 ` [patch 31/59] remove __devinit markings from rtc_sysfs_add_device() Chris Wright
2007-02-03  2:35 ` [patch 32/59] SPARC64: Set g4/g5 properly in sun4v dtlb-prot handling Chris Wright
2007-02-03  2:35 ` [patch 33/59] sis190: failure to set the MAC address from EEPROM Chris Wright
2007-02-03  2:35 ` [patch 34/59] knfsd: fix setting of ACL server versions Chris Wright
2007-02-03  2:35 ` [patch 35/59] knfsd: fix an NFSD bug with full sized, non-page-aligned reads Chris Wright
2007-02-03  2:35 ` [patch 36/59] knfsd: fix type mismatch with filldir_t used by nfsd Chris Wright
2007-02-03  2:35 ` [patch 37/59] knfsd: fix up some bit-rot in exp_export Chris Wright
2007-02-03  2:35 ` [patch 38/59] md: assorted md and raid1 one-liners Chris Wright
2007-02-03  2:35 ` [patch 39/59] md: make repair actually work for raid1 Chris Wright
2007-02-03  2:35 ` [patch 40/59] md: fix a few problems with the interface (sysfs and ioctl) to md Chris Wright
2007-02-03  2:35 ` [patch 41/59] md: fix potential memalloc deadlock in md Chris Wright
2007-02-03  2:35 ` [patch 42/59] libata: use kmap_atomic(KM_IRQ0) in SCSI simulator Chris Wright
2007-02-03  2:35 ` [patch 43/59] Dont allow the stack to grow into hugetlb reserved regions Chris Wright
2007-02-03  2:35 ` [patch 44/59] uml: fix signal frame alignment Chris Wright
2007-02-03  2:35 ` [patch 45/59] bonding: ARP monitoring broken on x86_64 Chris Wright
2007-02-03  2:35 ` [patch 46/59] jmicron: 40/80pin primary detection Chris Wright
2007-02-03  2:35 ` [patch 47/59] DECNET: Handle a failure in neigh_parms_alloc (take 2) Chris Wright
2007-02-03  2:35 ` [patch 48/59] SPARC32: Fix over-optimization by GCC near ip_fast_csum Chris Wright
2007-02-03  2:35 ` [patch 49/59] IPV4: Fix the fib trie iterator to work with a single entry routing tables Chris Wright
2007-02-03  2:35 ` [patch 50/59] IPV4: Fix single-entry /proc/net/fib_trie output Chris Wright
2007-02-03  2:35 ` [patch 51/59] AF_PACKET: Fix BPF handling Chris Wright
2007-02-03  2:35 ` [patch 52/59] AF_PACKET: Check device down state before hard header callbacks Chris Wright
2007-02-03  2:35 ` [patch 53/59] TCP: rare bad TCP checksum with 2.6.19 Chris Wright
2007-02-03  2:35 ` [patch 54/59] TCP: Fix sorting of SACK blocks Chris Wright
2007-02-03  2:35 ` [patch 55/59] TCP: skb is unexpectedly freed Chris Wright
2007-02-03  2:36 ` [patch 56/59] NETFILTER: xt_connbytes: fix division by zero Chris Wright
2007-02-03  2:36 ` [patch 57/59] SUNRPC: Give cloned RPC clients their own rpc_pipefs directory Chris Wright
2007-02-03  2:36 ` Chris Wright [this message]
2007-02-03  2:36 ` [patch 59/59] sched: fix cond_resched_softirq() offset Chris Wright
2007-02-03  2:59 ` [stable] [patch 00/59] -stable review Chris Wright
2007-02-04  6:08   ` Randy Dunlap
2007-02-04 13:36     ` Dave Jones
2007-02-04 17:30       ` Randy Dunlap

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