This is a note to let you know that I've just added the patch titled
arch/x86/oprofile/op_model_amd.c: Perform initialisation on a single CPU
to the 2.6.36-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arch-x86-oprofile-op_model_amd.c-perform-initialisation-on-a-single-cpu.patch
and it can be found in the queue-2.6.36 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From c7c25802b39c443b3745cfa973dc49a97a3491f8 Mon Sep 17 00:00:00 2001
From: Robert Richter <[email protected]>
Date: Mon, 3 Jan 2011 12:15:14 +0100
Subject: arch/x86/oprofile/op_model_amd.c: Perform initialisation on a single
CPU
From: Robert Richter <[email protected]>
commit c7c25802b39c443b3745cfa973dc49a97a3491f8 upstream.
Disable preemption in init_ibs(). The function only checks the
ibs capabilities and sets up pci devices (if necessary). It runs
only on one cpu but operates with the local APIC and some MSRs,
thus it is better to disable preemption.
[ 7.034377] BUG: using smp_processor_id() in preemptible [00000000] code:
modprobe/483
[ 7.034385] caller is setup_APIC_eilvt+0x155/0x180
[ 7.034389] Pid: 483, comm: modprobe Not tainted 2.6.37-rc1-20101110+ #1
[ 7.034392] Call Trace:
[ 7.034400] [<ffffffff812a2b72>] debug_smp_processor_id+0xd2/0xf0
[ 7.034404] [<ffffffff8101e985>] setup_APIC_eilvt+0x155/0x180
[ ... ]
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=22812
Reported-by: <[email protected]>
Signed-off-by: Robert Richter <[email protected]>
Cc: [email protected] <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
Cc: Dan Carpenter <[email protected]>
Cc: Andrew Morton <[email protected]>
LKML-Reference: <[email protected]>
[ small cleanups ]
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/x86/oprofile/op_model_amd.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
--- a/arch/x86/oprofile/op_model_amd.c
+++ b/arch/x86/oprofile/op_model_amd.c
@@ -484,21 +484,29 @@ static int __init_ibs_nmi(void)
return 0;
}
-/* initialize the APIC for the IBS interrupts if available */
+/*
+ * check and reserve APIC extended interrupt LVT offset for IBS if
+ * available
+ *
+ * init_ibs() preforms implicitly cpu-local operations, so pin this
+ * thread to its current CPU
+ */
+
static void init_ibs(void)
{
- ibs_caps = get_ibs_caps();
+ preempt_disable();
+ ibs_caps = get_ibs_caps();
if (!ibs_caps)
- return;
+ goto out;
- if (__init_ibs_nmi()) {
+ if (__init_ibs_nmi() < 0)
ibs_caps = 0;
- return;
- }
+ else
+ printk(KERN_INFO "oprofile: AMD IBS detected (0x%08x)\n",
ibs_caps);
- printk(KERN_INFO "oprofile: AMD IBS detected (0x%08x)\n",
- (unsigned)ibs_caps);
+out:
+ preempt_enable();
}
static int (*create_arch_files)(struct super_block *sb, struct dentry *root);
Patches currently in stable-queue which might be from [email protected] are
queue-2.6.36/arch-x86-oprofile-op_model_amd.c-perform-initialisation-on-a-single-cpu.patch
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