Commit-ID: fa2a79ce6aef5de35a4d50487da35deb6b634944
Gitweb: http://git.kernel.org/tip/fa2a79ce6aef5de35a4d50487da35deb6b634944
Author: James Custer <jcuster@xxxxxxx>
AuthorDate: Sun, 2 Nov 2014 12:16:39 -0600
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Mon, 3 Nov 2014 13:49:24 +0100
x86: UV BAU: Avoid NULL pointer reference in ptc_seq_show
In init_per_cpu(), when get_cpu_topology() fails, init_per_cpu_tunables()
is not called afterwards. This means that bau_control->statp is NULL.
If a user then reads /proc/sgi_uv/ptc_statistics ptc_seq_show() references
a NULL pointer. Therefore, since uv_bau_init calls set_bau_off when
init_per_cpu() fails, we add code that detects when the bau is off in
ptc_seq_show() to avoid referencing a NULL pointer.
Signed-off-by: James Custer <jcuster@xxxxxxx>
Cc: Russ Anderson <rja@xxxxxxx>
Link: http://lkml.kernel.org/r/1414952199-185319-2-git-send-email-jcuster@xxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
arch/x86/platform/uv/tlb_uv.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index 3968d67..570b1b1 100644
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -1384,6 +1384,10 @@ static int ptc_seq_show(struct seq_file *file, void *data)
}
if (cpu < num_possible_cpus() && cpu_online(cpu)) {
bcp = &per_cpu(bau_control, cpu);
+ if (bcp->nobau) {
+ seq_printf(file, "cpu %d bau disabled\n", cpu);
+ return 0;
+ }
stat = bcp->statp;
/* source side statistics */
seq_printf(file,
--
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