Messages in this thread Patch in this message | | | Subject | [PATCH] x86, UV: null pointer in uv_flush_tlb_others() | From | cpw <> | Date | Tue, 03 Dec 2013 17:15:30 -0600 |
| |
The SGI UV tlb shootdown code panics the system with a null pointer deference if 'nobau' is specified on the boot commandline.
uv_flush_tlb_other() gets called for every flush, whether the BAU is disabled or not. It should not be keeping the s_enters statistic while the BAU is disabled. The panic occurs because, during initialization, init_per_cpu_tunables() does not set the bcp->statp pointer if nobau was specified.
The code is the same in the 3.12.2 tree.
Cc: <stable@vger.kernel.org> # 3.12.x Signed-off-by: Cliff Wickman <cpw@sgi.com> --- arch/x86/platform/uv/tlb_uv.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
Index: linux/arch/x86/platform/uv/tlb_uv.c =================================================================== --- linux.orig/arch/x86/platform/uv/tlb_uv.c +++ linux/arch/x86/platform/uv/tlb_uv.c @@ -1070,12 +1070,13 @@ const struct cpumask *uv_flush_tlb_other unsigned long status; bcp = &per_cpu(bau_control, cpu); - stat = bcp->statp; - stat->s_enters++; if (bcp->nobau) return cpumask; + stat = bcp->statp; + stat->s_enters++; + if (bcp->busy) { descriptor_status = read_lmmr(UVH_LB_BAU_SB_ACTIVATION_STATUS_0);
| |