From: James Custer <[email protected]> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== commit fa2a79ce6aef5de35a4d50487da35deb6b634944 upstream. 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 <[email protected]> Cc: Russ Anderson <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Jiri Slaby <[email protected]> --- 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 efe4d7220397..a6b5affb024a 100644 --- a/arch/x86/platform/uv/tlb_uv.c +++ b/arch/x86/platform/uv/tlb_uv.c @@ -1367,6 +1367,10 @@ 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, -- 2.2.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
