Re: [PATCH 3 of 4] xentrace: reduce size of extradata in trace_irq_mask()

[George Dunlap <george.dunlap@citrix.com>]

Acked-by: George Dunlap <george.dunlap@eu.citrix.com>

On Fri, 2011-07-15 at 16:38 +0100, Olaf Hering wrote:
> # HG changeset patch
> # User Olaf Hering <olaf@aepfle.de>
> # Date 1310743144 -7200
> # Node ID 6e4aef7b5051e18f19f2367a4439bba8f495335c
> # Parent  e0ff4eea0432e0af3210e090a47414a0126e9904
> xentrace: reduce size of extradata in trace_irq_mask()
> 
> Reduce size of extra_data in to avoid possible crash in trace_var.
> 
> (XEN) Assertion 'extra_word <= TRACE_EXTRA_MAX' failed at trace.c:687
> (XEN) Xen call trace:
> (XEN)    [<ffff82c480128783>] __trace_var+0x4d/0x3b8
> (XEN)    [<ffff82c480162172>] trace_irq_mask+0x49/0x4b
> (XEN)    [<ffff82c4801631ae>] __assign_irq_vector+0x241/0x374
> (XEN)    [<ffff82c48015d813>] set_desc_affinity+0x5d/0xd4
> (XEN)    [<ffff82c480160708>] set_msi_affinity+0x44/0x1c1
> (XEN)    [<ffff82c480162938>] move_masked_irq+0x9c/0xcd
> (XEN)    [<ffff82c4801629a7>] move_native_irq+0x3e/0x53
> (XEN)    [<ffff82c48015d969>] ack_msi_irq+0x2c/0x6e
> (XEN)    [<ffff82c4801622e3>] do_IRQ+0x16f/0x66d
> 
> Signed-off-by: Olaf Hering <olaf@aepfle.de>
> 
> diff -r e0ff4eea0432 -r 6e4aef7b5051 xen/arch/x86/irq.c
> --- a/xen/arch/x86/irq.c
> +++ b/xen/arch/x86/irq.c
> @@ -77,10 +77,14 @@ void unlock_vector_lock(void)
>  static void trace_irq_mask(u32 event, int irq, int vector, cpumask_t *mask)
>  {
>      struct {
> -        int irq, vec;
> -        cpumask_t mask;
> -    } d = { irq, vector, *mask };
> -    trace_var(event, 1, sizeof(d), (unsigned char *)&d);
> +        unsigned int irq:16, vec:16;
> +        unsigned int mask[6];
> +    } d;
> +    d.irq = irq;
> +    d.vec = vector;
> +    memset(d.mask, 0, sizeof(d.mask));
> +    memcpy(d.mask, mask, min(sizeof(d.mask), sizeof(cpumask_t)));
> +    trace_var(event, 1, sizeof(d), &d);
>  }
>  
>  static int __init __bind_irq_vector(int irq, int vector, cpumask_t cpu_mask)