From mboxrd@z Thu Jan 1 00:00:00 1970 Reply-To: kernel-hardening@lists.openwall.com From: Andy Lutomirski Date: Wed, 15 Jun 2016 17:28:27 -0700 Message-Id: <31f2e076a21321eedd71babb1a4791c5ad171a20.1466036668.git.luto@kernel.org> In-Reply-To: References: In-Reply-To: References: Subject: [kernel-hardening] [PATCH 05/13] mm: Move memcg stack accounting to account_kernel_stack To: "linux-kernel@vger.kernel.org" , x86@kernel.org, Borislav Petkov Cc: Nadav Amit , Kees Cook , Brian Gerst , "kernel-hardening@lists.openwall.com" , Linus Torvalds , Josh Poimboeuf , Andy Lutomirski , Vladimir Davydov , Johannes Weiner , Michal Hocko , linux-mm@kvack.org List-ID: We should account for stacks regardless of stack size. Move it into account_kernel_stack. Fixes: 12580e4b54ba8 ("mm: memcontrol: report kernel stack usage in cgroup2 memory.stat") Cc: Vladimir Davydov Cc: Johannes Weiner Cc: Michal Hocko Cc: linux-mm@kvack.org Signed-off-by: Andy Lutomirski --- kernel/fork.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index 95bebde59d79..59e52f2120a3 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -165,20 +165,12 @@ static struct thread_info *alloc_thread_info_node(struct task_struct *tsk, struct page *page = alloc_kmem_pages_node(node, THREADINFO_GFP, THREAD_SIZE_ORDER); - if (page) - memcg_kmem_update_page_stat(page, MEMCG_KERNEL_STACK, - 1 << THREAD_SIZE_ORDER); - return page ? page_address(page) : NULL; } static inline void free_thread_info(struct thread_info *ti) { - struct page *page = virt_to_page(ti); - - memcg_kmem_update_page_stat(page, MEMCG_KERNEL_STACK, - -(1 << THREAD_SIZE_ORDER)); - __free_kmem_pages(page, THREAD_SIZE_ORDER); + free_kmem_pages((unsigned long)ti, THREAD_SIZE_ORDER); } # else static struct kmem_cache *thread_info_cache; @@ -227,6 +219,11 @@ static void account_kernel_stack(struct thread_info *ti, int account) mod_zone_page_state(zone, NR_KERNEL_STACK, THREAD_SIZE / PAGE_SIZE * account); + + /* All stack pages belong to the same memcg. */ + memcg_kmem_update_page_stat( + virt_to_page(ti), MEMCG_KERNEL_STACK, + account * (THREAD_SIZE / PAGE_SIZE)); } void free_task(struct task_struct *tsk) -- 2.7.4