Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "18 patches.

  Subsystems affected by this patch series: mm (pagealloc, memcg, kasan,
  memory-failure, and highmem), ubsan, proc, and MAINTAINERS"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  MAINTAINERS: add a couple more files to the Clang/LLVM section
  proc_sysctl: fix oops caused by incorrect command parameters
  powerpc/mm/highmem: use __set_pte_at() for kmap_local()
  mips/mm/highmem: use set_pte() for kmap_local()
  mm/highmem: prepare for overriding set_pte_at()
  sparc/mm/highmem: flush cache and TLB
  mm: fix page reference leak in soft_offline_page()
  ubsan: disable unsigned-overflow check for i386
  kasan, mm: fix resetting page_alloc tags for HW_TAGS
  kasan, mm: fix conflicts with init_on_alloc/free
  kasan: fix HW_TAGS boot parameters
  kasan: fix incorrect arguments passing in kasan_add_zero_shadow
  kasan: fix unaligned address is unhandled in kasan_remove_zero_shadow
  mm: fix numa stats for thp migration
  mm: memcg: fix memcg file_dirty numa stat
  mm: memcg/slab: optimize objcg stock draining
  mm: fix initialization of struct page for holes in memory layout
  x86/setup: don't remove E820_TYPE_RAM for pfn 0

1 files changed, 6 insertions, 1 deletions

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 317899222d7f..d2018f70d1fa 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -1770,6 +1770,12 @@ static int process_sysctl_arg(char *param, char *val,
 			return 0;
 	}
 
+	if (!val)
+		return -EINVAL;
+	len = strlen(val);
+	if (len == 0)
+		return -EINVAL;
+
 	/*
 	 * To set sysctl options, we use a temporary mount of proc, look up the
 	 * respective sys/ file and write to it. To avoid mounting it when no
@@ -1811,7 +1817,6 @@ static int process_sysctl_arg(char *param, char *val,
 				file, param, val);
 		goto out;
 	}
-	len = strlen(val);
 	wret = kernel_write(file, val, len, &pos);
 	if (wret < 0) {
 		err = wret;