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authorStefan Bader <stefan.bader@canonical.com>2008-09-27 11:07:30 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2008-10-18 10:49:11 -0700
commit7ae3a769f9cbde6564b7335b0ea45d19066c7f7c (patch)
treebc7a2e4ed5b999616967c97f12e3d1db27a4c6f9
parentd49d50a98a807e9322bc287e5da26d70168cd4c0 (diff)
downloadlwn-7ae3a769f9cbde6564b7335b0ea45d19066c7f7c.tar.gz
lwn-7ae3a769f9cbde6564b7335b0ea45d19066c7f7c.zip
x86: Reserve FIRST_DEVICE_VECTOR in used_vectors bitmap.
Not in upstream above 2.6.27 due to change in the way this code works (has been fixed differently there.) Someone from the community found out, that after repeatedly unloading and loading a device driver that uses MSI IRQs, the system eventually assigned the vector initially reserved for IRQ0 to the device driver. The reason for this is, that although IRQ0 is tied to the FIRST_DEVICE_VECTOR when declaring the irq_vector table, the corresponding bit in the used_vectors map is not set. So, if vectors are released and assigned often enough, the vector will get assigned to another interrupt. This happens more often with MSI interrupts as those are exclusively using a vector. Fix this by setting the bit for the FIRST_DEVICE_VECTOR in the bitmap. Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--arch/x86/kernel/io_apic_32.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
index 09cddb57bec4..bfd9fc5d1556 100644
--- a/arch/x86/kernel/io_apic_32.c
+++ b/arch/x86/kernel/io_apic_32.c
@@ -2314,6 +2314,9 @@ void __init setup_IO_APIC(void)
for (i = first_system_vector; i < NR_VECTORS; i++)
set_bit(i, used_vectors);
+ /* Mark FIRST_DEVICE_VECTOR which is assigned to IRQ0 as used. */
+ set_bit(FIRST_DEVICE_VECTOR, used_vectors);
+
enable_IO_APIC();
io_apic_irqs = ~PIC_IRQS;