linux-kernel - [tip:x86/apic] x86, ioapic: Fix potential resume deadlock

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Date:	Fri, 20 May 2011 13:36:58 GMT
From:	tip-bot for Daniel J Blueman <daniel.blueman@...il.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
	daniel.blueman@...il.com, suresh.b.siddha@...el.com,
	tglx@...utronix.de, mingo@...e.hu
Subject: [tip:x86/apic] x86, ioapic: Fix potential resume deadlock

Commit-ID:  b64ce24daffb634b5b3133a2e411bd4de50654e8
Gitweb:     http://git.kernel.org/tip/b64ce24daffb634b5b3133a2e411bd4de50654e8
Author:     Daniel J Blueman <daniel.blueman@...il.com>
AuthorDate: Wed, 18 May 2011 16:31:31 -0700
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Fri, 20 May 2011 13:40:41 +0200

x86, ioapic: Fix potential resume deadlock

Fix a potential deadlock when resuming; here the calling
function has disabled interrupts, so we cannot sleep.

Change the memory allocation flag from GFP_KERNEL to GFP_ATOMIC.

TODO: We can do away with this memory allocation during resume
      by reusing the ioapic suspend/resume code that uses boot time
      allocated buffers, but we want to keep this -stable patch
      simple.

Signed-off-by: Daniel J Blueman <daniel.blueman@...il.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@...el.com>
Cc: <stable@...nel.org> # v2.6.38/39
Link: http://lkml.kernel.org/r/20110518233157.385970138@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 arch/x86/kernel/apic/io_apic.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 45fd33d..df63620 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -621,14 +621,14 @@ struct IO_APIC_route_entry **alloc_ioapic_entries(void)
 	struct IO_APIC_route_entry **ioapic_entries;
 
 	ioapic_entries = kzalloc(sizeof(*ioapic_entries) * nr_ioapics,
-				GFP_KERNEL);
+				GFP_ATOMIC);
 	if (!ioapic_entries)
 		return 0;
 
 	for (apic = 0; apic < nr_ioapics; apic++) {
 		ioapic_entries[apic] =
 			kzalloc(sizeof(struct IO_APIC_route_entry) *
-				nr_ioapic_registers[apic], GFP_KERNEL);
+				nr_ioapic_registers[apic], GFP_ATOMIC);
 		if (!ioapic_entries[apic])
 			goto nomem;
 	}
--
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