[tip:x86/urgent] x86/mm/32: Set the '__vmalloc_start_set' flag in initmem_init()

[tip-bot for Laura Abbott]

Commit-ID:  861ce4a3244c21b0af64f880d5bfe5e6e2fb9e4a
Gitweb:     http://git.kernel.org/tip/861ce4a3244c21b0af64f880d5bfe5e6e2fb9e4a
Author:     Laura Abbott <labbott@xxxxxxxxxx>
AuthorDate: Mon, 8 May 2017 14:23:16 -0700
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 9 May 2017 08:12:27 +0200

x86/mm/32: Set the '__vmalloc_start_set' flag in initmem_init()

'__vmalloc_start_set' currently only gets set in initmem_init() when
!CONFIG_NEED_MULTIPLE_NODES. This breaks detection of vmalloc address
with virt_addr_valid() with CONFIG_NEED_MULTIPLE_NODES=y, causing
a kernel crash:

  [mm/usercopy] 517e1fbeb6: kernel BUG at arch/x86/mm/physaddr.c:78!

Set '__vmalloc_start_set' appropriately for that case as well.

Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx>
Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Fixes: dc16ecf7fd1f ("x86-32: use specific __vmalloc_start_set flag in __virt_addr_valid")
Link: http://lkml.kernel.org/r/1494278596-30373-1-git-send-email-labbott@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/mm/numa_32.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/mm/numa_32.c b/arch/x86/mm/numa_32.c
index 6b7ce62..aca6295 100644
--- a/arch/x86/mm/numa_32.c
+++ b/arch/x86/mm/numa_32.c
@@ -100,5 +100,6 @@ void __init initmem_init(void)
 	printk(KERN_DEBUG "High memory starts at vaddr %08lx\n",
 			(ulong) pfn_to_kaddr(highstart_pfn));
 
+	__vmalloc_start_set = true;
 	setup_bootmem_allocator();
 }