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xen: off by one errors in multicalls.c

commit f124c6ae59e193705c9ddac57684d50006d710e6 upstream.

b->args[] has MC_ARGS elements, so the comparison here should be
">=" instead of ">".  Otherwise we read past the end of the array
one space.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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1 parent 13fbebb commit a8ae639a3f453481caf7dbe1d85725c8e11a3811 @error27 error27 committed with Jun 3, 2011
Showing with 6 additions and 6 deletions.
  1. +6 −6 arch/x86/xen/multicalls.c
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@@ -189,10 +189,10 @@ struct multicall_space __xen_mc_entry(size_t args)
unsigned argidx = roundup(b->argidx, sizeof(u64));
BUG_ON(preemptible());
- BUG_ON(b->argidx > MC_ARGS);
+ BUG_ON(b->argidx >= MC_ARGS);
if (b->mcidx == MC_BATCH ||
- (argidx + args) > MC_ARGS) {
+ (argidx + args) >= MC_ARGS) {
mc_stats_flush(b->mcidx == MC_BATCH ? FL_SLOTS : FL_ARGS);
xen_mc_flush();
argidx = roundup(b->argidx, sizeof(u64));
@@ -206,7 +206,7 @@ struct multicall_space __xen_mc_entry(size_t args)
ret.args = &b->args[argidx];
b->argidx = argidx + args;
- BUG_ON(b->argidx > MC_ARGS);
+ BUG_ON(b->argidx >= MC_ARGS);
return ret;
}
@@ -216,22 +216,22 @@ struct multicall_space xen_mc_extend_args(unsigned long op, size_t size)
struct multicall_space ret = { NULL, NULL };
BUG_ON(preemptible());
- BUG_ON(b->argidx > MC_ARGS);
+ BUG_ON(b->argidx >= MC_ARGS);
if (b->mcidx == 0)
return ret;
if (b->entries[b->mcidx - 1].op != op)
return ret;
- if ((b->argidx + size) > MC_ARGS)
+ if ((b->argidx + size) >= MC_ARGS)
return ret;
ret.mc = &b->entries[b->mcidx - 1];
ret.args = &b->args[b->argidx];
b->argidx += size;
- BUG_ON(b->argidx > MC_ARGS);
+ BUG_ON(b->argidx >= MC_ARGS);
return ret;
}

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