[Xen-devel] [PATCH 3 of 4] xentrace: reduce size of extradata in trace_irq_mask()

[Olaf Hering <olaf@xxxxxxxxx>]

# HG changeset patch
# User Olaf Hering <olaf@xxxxxxxxx>
# 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@xxxxxxxxx>

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)

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