* Alan Cox ([email protected]) wrote:
> I'd agree entirely with Dave - if you are applying a fix to something
> that is currently totally broken which may make it work and which doesn't
> affect any other bit of code then it goes into the stable tree.
And, in this case we're in luck. It's not released in any -stable tree
yet (it's queued for the next release). So there's plenty of time to
fix it up before next -stable release.
Something like below should fix it.
thanks,
-chris
--
Subject: [PATCH] x86: fix oprofile double free
From: Chris Wright <[email protected]>
Chuck reports that the recent fix from Andi to oprofile
6c977aad03a18019015035958c65b6729cd0574c introduces a double
free. Each cpu's cpu_msrs is setup to point to cpu 0's, which
causes free_msrs to free cpu 0's pointers for_each_possible_cpu.
Rather than copy the pointers, do a deep copy instead.
Signed-off-by: Chris Wright <[email protected]>
---
arch/i386/oprofile/nmi_int.c | 10 ++++++++--
1 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/i386/oprofile/nmi_int.c b/arch/i386/oprofile/nmi_int.c
index a7c0783..0c39443 100644
--- a/arch/i386/oprofile/nmi_int.c
+++ b/arch/i386/oprofile/nmi_int.c
@@ -211,8 +211,14 @@ static int nmi_setup(void)
/* Assume saved/restored counters are the same on all CPUs */
model->fill_in_addresses(&cpu_msrs[0]);
for_each_possible_cpu (cpu) {
- if (cpu != 0)
- cpu_msrs[cpu] = cpu_msrs[0];
+ if (cpu != 0) {
+ memcpy(cpu_msrs[cpu].counters, cpu_msrs[0].counters,
+ sizeof(struct op_msr) * model->num_counters);
+
+ memcpy(cpu_msrs[cpu].controls, cpu_msrs[0].controls,
+ sizeof(struct op_msr) * model->num_controls);
+ }
+
}
on_each_cpu(nmi_save_registers, NULL, 0, 1);
on_each_cpu(nmi_cpu_setup, NULL, 0, 1);
-
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