linux-kernel - [076/146] x86, ioapic: Fix potential resume deadlock

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Date:	Wed, 01 Jun 2011 17:00:12 +0900
From:	Greg KH <gregkh@...e.de>
To:	linux-kernel@...r.kernel.org, stable@...nel.org
Cc:	stable-review@...nel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
	Daniel J Blueman <daniel.blueman@...il.com>,
	Suresh Siddha <suresh.b.siddha@...el.com>,
	Ingo Molnar <mingo@...e.hu>,
	Greg Kroah-Hartman <gregkh@...e.de>
Subject: [076/146] x86, ioapic: Fix potential resume deadlock

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

------------------

From: Daniel J Blueman <daniel.blueman@...il.com>

commit b64ce24daffb634b5b3133a2e411bd4de50654e8 upstream.

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>
Link: http://lkml.kernel.org/r/20110518233157.385970138@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Ingo Molnar <mingo@...e.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>

---
 arch/x86/kernel/apic/io_apic.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -615,14 +615,14 @@ struct IO_APIC_route_entry **alloc_ioapi
 	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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