From: Yong-Xuan Wang <yongxuan.wang@xxxxxxxxxx> [ Upstream commit 198102c9103fc78d8478495971947af77edb05c1 ] The cacheinfo sets up the shared_cpu_map by checking whether the caches with the same index are shared between CPUs. However, this will trigger slab-out-of-bounds access if the CPUs do not have the same cache hierarchy. Another problem is the mismatched shared_cpu_map when the shared cache does not have the same index between CPUs. CPU0 I D L3 index 0 1 2 x ^ ^ ^ ^ index 0 1 2 3 CPU1 I D L2 L3 This patch checks each cache is shared with all caches on other CPUs. Reviewed-by: Pierre Gondois <pierre.gondois@xxxxxxx> Signed-off-by: Yong-Xuan Wang <yongxuan.wang@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230117105133.4445-2-yongxuan.wang@xxxxxxxxxx Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/base/cacheinfo.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index 950b22cdb5f7c..f05acf3c16c6b 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -256,7 +256,7 @@ static int cache_shared_cpu_map_setup(unsigned int cpu) { struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu); struct cacheinfo *this_leaf, *sib_leaf; - unsigned int index; + unsigned int index, sib_index; int ret = 0; if (this_cpu_ci->cpu_map_populated) @@ -284,11 +284,13 @@ static int cache_shared_cpu_map_setup(unsigned int cpu) if (i == cpu || !sib_cpu_ci->info_list) continue;/* skip if itself or no cacheinfo */ - - sib_leaf = per_cpu_cacheinfo_idx(i, index); - if (cache_leaves_are_shared(this_leaf, sib_leaf)) { - cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map); - cpumask_set_cpu(i, &this_leaf->shared_cpu_map); + for (sib_index = 0; sib_index < cache_leaves(i); sib_index++) { + sib_leaf = per_cpu_cacheinfo_idx(i, sib_index); + if (cache_leaves_are_shared(this_leaf, sib_leaf)) { + cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map); + cpumask_set_cpu(i, &this_leaf->shared_cpu_map); + break; + } } } /* record the maximum cache line size */ @@ -302,7 +304,7 @@ static int cache_shared_cpu_map_setup(unsigned int cpu) static void cache_shared_cpu_map_remove(unsigned int cpu) { struct cacheinfo *this_leaf, *sib_leaf; - unsigned int sibling, index; + unsigned int sibling, index, sib_index; for (index = 0; index < cache_leaves(cpu); index++) { this_leaf = per_cpu_cacheinfo_idx(cpu, index); @@ -313,9 +315,14 @@ static void cache_shared_cpu_map_remove(unsigned int cpu) if (sibling == cpu || !sib_cpu_ci->info_list) continue;/* skip if itself or no cacheinfo */ - sib_leaf = per_cpu_cacheinfo_idx(sibling, index); - cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map); - cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map); + for (sib_index = 0; sib_index < cache_leaves(sibling); sib_index++) { + sib_leaf = per_cpu_cacheinfo_idx(sibling, sib_index); + if (cache_leaves_are_shared(this_leaf, sib_leaf)) { + cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map); + cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map); + break; + } + } } } } -- 2.39.2
