From: Len Brown <lenb@kernel.org>
To: linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
Len Brown <len.brown@intel.com>
Subject: [PATCH 29/30] ACPI idle, CPU hotplug: Fix NULL pointer dereference during hotplug
Date: Tue, 9 Oct 2012 01:54:19 -0400 [thread overview]
Message-ID: <cf31cd1a0c692a1445c80756055875088fa29982.1349761836.git.len.brown@intel.com> (raw)
In-Reply-To: <1349762060-25334-1-git-send-email-lenb@kernel.org>
In-Reply-To: <e3f25e6e5836c4790fbe395ff42e241f372d859d.1349761836.git.len.brown@intel.com>
From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
On a KVM guest, when a CPU is taken offline and brought back online, we hit
the following NULL pointer dereference:
[ 45.400843] Unregister pv shared memory for cpu 1
[ 45.412331] smpboot: CPU 1 is now offline
[ 45.529894] SMP alternatives: lockdep: fixing up alternatives
[ 45.533472] smpboot: Booting Node 0 Processor 1 APIC 0x1
[ 45.411526] kvm-clock: cpu 1, msr 0:7d14601, secondary cpu clock
[ 45.571370] KVM setup async PF for cpu 1
[ 45.572331] kvm-stealtime: cpu 1, msr 7d0e040
[ 45.575031] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 45.576017] IP: [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[ 45.576017] PGD 5dfb067 PUD 5da8067 PMD 0
[ 45.576017] Oops: 0000 [#1] SMP
[ 45.576017] Modules linked in:
[ 45.576017] CPU 0
[ 45.576017] Pid: 607, comm: stress_cpu_hotp Not tainted 3.6.0-padata-tp-debug #3 Bochs Bochs
[ 45.576017] RIP: 0010:[<ffffffff81519f98>] [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[ 45.576017] RSP: 0018:ffff880005d93ce8 EFLAGS: 00010286
[ 45.576017] RAX: ffff880005d93fd8 RBX: 0000000000000000 RCX: 0000000000000006
[ 45.576017] RDX: 0000000000000006 RSI: 2222222222222222 RDI: 0000000000000000
[ 45.576017] RBP: ffff880005d93cf8 R08: 2222222222222222 R09: 2222222222222222
[ 45.576017] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 45.576017] R13: 0000000000000000 R14: ffffffff81c8cca0 R15: 0000000000000001
[ 45.576017] FS: 00007f91936ae700(0000) GS:ffff880007c00000(0000) knlGS:0000000000000000
[ 45.576017] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 45.576017] CR2: 0000000000000000 CR3: 0000000005db3000 CR4: 00000000000006f0
[ 45.576017] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 45.576017] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 45.576017] Process stress_cpu_hotp (pid: 607, threadinfo ffff880005d92000, task ffff8800066bbf40)
[ 45.576017] Stack:
[ 45.576017] ffff880007a96400 0000000000000000 ffff880005d93d28 ffffffff813ac689
[ 45.576017] ffff880007a96400 ffff880007a96400 0000000000000002 ffffffff81cd8d01
[ 45.576017] ffff880005d93d58 ffffffff813aa498 0000000000000001 00000000ffffffdd
[ 45.576017] Call Trace:
[ 45.576017] [<ffffffff813ac689>] acpi_processor_hotplug+0x55/0x97
[ 45.576017] [<ffffffff813aa498>] acpi_cpu_soft_notify+0x93/0xce
[ 45.576017] [<ffffffff816ae47d>] notifier_call_chain+0x5d/0x110
[ 45.576017] [<ffffffff8109730e>] __raw_notifier_call_chain+0xe/0x10
[ 45.576017] [<ffffffff81069050>] __cpu_notify+0x20/0x40
[ 45.576017] [<ffffffff81069085>] cpu_notify+0x15/0x20
[ 45.576017] [<ffffffff816978f1>] _cpu_up+0xee/0x137
[ 45.576017] [<ffffffff81697983>] cpu_up+0x49/0x59
[ 45.576017] [<ffffffff8168758d>] store_online+0x9d/0xe0
[ 45.576017] [<ffffffff8140a9f8>] dev_attr_store+0x18/0x30
[ 45.576017] [<ffffffff812322c0>] sysfs_write_file+0xe0/0x150
[ 45.576017] [<ffffffff811b389c>] vfs_write+0xac/0x180
[ 45.576017] [<ffffffff811b3be2>] sys_write+0x52/0xa0
[ 45.576017] [<ffffffff816b31e9>] system_call_fastpath+0x16/0x1b
[ 45.576017] Code: 48 c7 c7 40 e5 ca 81 e8 07 d0 18 00 5d c3 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 10 48 89 5d f0 4c 89 65 f8 48 89 fb <f6> 07 02 75 13 48 8b 5d f0 4c 8b 65 f8 c9 c3 66 0f 1f 84 00 00
[ 45.576017] RIP [<ffffffff81519f98>] cpuidle_disable_device+0x18/0x80
[ 45.576017] RSP <ffff880005d93ce8>
[ 45.576017] CR2: 0000000000000000
[ 45.656079] ---[ end trace 433d6c9ac0b02cef ]---
Analysis:
Commit 3d339dc (cpuidle / ACPI : move cpuidle_device field out of the
acpi_processor_power structure()) made the allocation of the dev structure
(struct cpuidle) of a CPU dynamic, whereas previously it was statically
allocated. And this dynamic allocation occurs in acpi_processor_power_init()
if pr->flags.power evaluates to non-zero.
On KVM guests, pr->flags.power evaluates to zero, hence dev is never
allocated. This causes the NULL pointer (dev) dereference in
cpuidle_disable_device() during a subsequent CPU online operation. Fix this
by ensuring that dev is non-NULL before dereferencing.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Len Brown <len.brown@intel.com>
---
drivers/cpuidle/cpuidle.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index e28f6ea..7f15b85 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -368,7 +368,7 @@ EXPORT_SYMBOL_GPL(cpuidle_enable_device);
*/
void cpuidle_disable_device(struct cpuidle_device *dev)
{
- if (!dev->enabled)
+ if (!dev || !dev->enabled)
return;
if (!cpuidle_get_driver() || !cpuidle_curr_governor)
return;
--
1.8.0.rc1
next prev parent reply other threads:[~2012-10-09 6:04 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-09 5:53 ACPI & Thermal patches for Linux-3.7-merge Len Brown
2012-10-09 5:53 ` [PATCH 01/30] Thermal: Introduce multiple cooling states support Len Brown
2012-10-09 5:53 ` [PATCH 02/30] Thermal: Introduce cooling states range support Len Brown
2012-10-09 5:53 ` [PATCH 03/30] Thermal: set upper and lower limits Len Brown
2012-10-09 5:53 ` [PATCH 04/30] Thermal: Introduce .get_trend() callback Len Brown
2012-10-09 5:53 ` [PATCH 05/30] Thermal: Remove tc1/tc2 in generic thermal layer Len Brown
2012-10-09 5:53 ` [PATCH 06/30] Thermal: Introduce thermal_zone_trip_update() Len Brown
2012-10-09 5:53 ` [PATCH 07/30] Thermal: rename structure thermal_cooling_device_instance to thermal_instance Len Brown
2012-10-09 5:53 ` [PATCH 08/30] Thermal: Rename thermal_zone_device.cooling_devices Len Brown
2012-10-09 5:53 ` [PATCH 09/30] Thermal: Rename thermal_instance.node to thermal_instance.tz_node Len Brown
2012-10-09 5:54 ` [PATCH 10/30] Thermal: List thermal_instance in thermal_cooling_device Len Brown
2012-10-09 5:54 ` [PATCH 11/30] Thermal: Introduce simple arbitrator for setting device cooling state Len Brown
2012-10-09 5:54 ` [PATCH 12/30] Thermal: Unify the code for both active and passive cooling Len Brown
2012-10-09 5:54 ` [PATCH 13/30] Thermal: Introduce locking for cdev.thermal_instances list Len Brown
2012-10-09 5:54 ` [PATCH 14/30] thermal: fix potential out-of-bounds memory access Len Brown
2012-10-09 5:54 ` [PATCH 15/30] thermal: add Renesas R-Car thermal sensor support Len Brown
2012-10-09 5:54 ` [PATCH 16/30] thermal: Fix potential NULL pointer accesses Len Brown
2012-10-09 5:54 ` [PATCH 17/30] Fix a build error Len Brown
2012-10-09 5:54 ` [PATCH 18/30] thermal: add generic cpufreq cooling implementation Len Brown
2012-10-09 5:54 ` [PATCH 19/30] hwmon: exynos4: move thermal sensor driver to driver/thermal directory Len Brown
2012-10-09 5:54 ` [PATCH 20/30] thermal: exynos5: add exynos5250 thermal sensor driver support Len Brown
2012-10-09 5:54 ` [PATCH 21/30] thermal: exynos: register the tmu sensor with the kernel thermal layer Len Brown
2012-10-09 5:54 ` [PATCH 22/30] ARM: exynos: add thermal sensor driver platform data support Len Brown
2012-10-09 5:54 ` [PATCH 23/30] thermal: exynos: Use devm_* functions Len Brown
2012-10-09 5:54 ` [PATCH 24/30] Thermal: Fix bug on cpu_cooling, cooling device's id conflict problem Len Brown
2012-10-09 5:54 ` [PATCH 25/30] thermal: Exynos: Fix NULL pointer dereference in exynos_unregister_thermal() Len Brown
2012-10-09 5:54 ` [PATCH 26/30] ACPI: EC: Make the GPE storm threshold a module parameter Len Brown
2012-10-09 5:54 ` [PATCH 27/30] ACPI: EC: Add a quirk for CLEVO M720T/M730T laptop Len Brown
2012-10-09 6:16 ` Jonathan Nieder
2012-10-09 6:22 ` Feng Tang
2012-10-09 6:59 ` Jonathan Nieder
2012-10-09 7:19 ` Feng Tang
2012-10-09 5:54 ` [PATCH 28/30] cpuidle / ACPI: fix potential NULL pointer dereference Len Brown
2012-10-09 5:54 ` Len Brown [this message]
2012-10-09 5:54 ` [PATCH 30/30] tools/power/acpi/acpidump: remove duplicated include from acpidump.c Len Brown
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