On architectures that depend on DT for obtaining cache hierarcy, we need to validate the device node for all the cache indices, failing to do so might result in wrong information being exposed to the userspace.
This is quite possible on initial/incomplete versions of the device trees. In such cases, it's better to bail out if all the required device nodes are not present. This patch adds checks for the validation of device node for all the caches and doesn't initialise the cacheinfo if there's any error. Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org> Reported-by: Mark Rutland <mark.rutl...@arm.com> Acked-by: Mark Rutland <mark.rutl...@arm.com> Signed-off-by: Sudeep Holla <sudeep.ho...@arm.com> --- drivers/base/cacheinfo.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) Hi Greg, Can you please pick this up as a bug fix ? Without this there's possibility that erroneous information is exposed to userspace on architecture depending on DT especially if DT lacks cache hierarchy information. There are many arm64 device trees without cache hierarchy which results in exposing wrong cacheinfo to the user space. It would be good to get this included as bug fix for 4.0 This was previously posted a while ago[1] Regards, Sudeep [1] https://lkml.org/lkml/2015/2/16/264 diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c index 6e64563361f0..9c2ba1c97c42 100644 --- a/drivers/base/cacheinfo.c +++ b/drivers/base/cacheinfo.c @@ -62,15 +62,21 @@ static int cache_setup_of_node(unsigned int cpu) return -ENOENT; } - while (np && index < cache_leaves(cpu)) { + while (index < cache_leaves(cpu)) { this_leaf = this_cpu_ci->info_list + index; if (this_leaf->level != 1) np = of_find_next_cache_node(np); else np = of_node_get(np);/* cpu node itself */ + if (!np) + break; this_leaf->of_node = np; index++; } + + if (index != cache_leaves(cpu)) /* not all OF nodes populated */ + return -ENOENT; + return 0; } @@ -189,8 +195,11 @@ static int detect_cache_attributes(unsigned int cpu) * will be set up here only if they are not populated already */ ret = cache_shared_cpu_map_setup(cpu); - if (ret) + if (ret) { + pr_warn("Unable to detect cache hierarcy from DT for CPU %d\n", + cpu); goto free_ci; + } return 0; free_ci: -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
