Patch "staging: android: ion: Add __GFP_NOWARN for system contig heap" has been added to the 4.15-stable tree

Patch "staging: android: ion: Add __GFP_NOWARN for system contig heap" has been added to the 4.15-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    staging: android: ion: Add __GFP_NOWARN for system contig heap

to the 4.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     staging-android-ion-add-__gfp_nowarn-for-system-contig-heap.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 0c75f10312a35b149b2cebb1832316b35c2337ca Mon Sep 17 00:00:00 2001
From: Laura Abbott <labbott@redhat.com>
Date: Fri, 5 Jan 2018 11:14:08 -0800
Subject: staging: android: ion: Add __GFP_NOWARN for system contig heap

From: Laura Abbott <labbott@redhat.com>

commit 0c75f10312a35b149b2cebb1832316b35c2337ca upstream.

syzbot reported a warning from Ion:

  WARNING: CPU: 1 PID: 3485 at mm/page_alloc.c:3926

  ...
   __alloc_pages_nodemask+0x9fb/0xd80 mm/page_alloc.c:4252
  alloc_pages_current+0xb6/0x1e0 mm/mempolicy.c:2036
  alloc_pages include/linux/gfp.h:492 [inline]
  ion_system_contig_heap_allocate+0x40/0x2c0
  drivers/staging/android/ion/ion_system_heap.c:374
  ion_buffer_create drivers/staging/android/ion/ion.c:93 [inline]
  ion_alloc+0x2c1/0x9e0 drivers/staging/android/ion/ion.c:420
  ion_ioctl+0x26d/0x380 drivers/staging/android/ion/ion-ioctl.c:84
  vfs_ioctl fs/ioctl.c:46 [inline]
  do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686
  SYSC_ioctl fs/ioctl.c:701 [inline]
  SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692

This is a warning about attempting to allocate order > MAX_ORDER. This
is coming from a userspace Ion allocation request. Since userspace is
free to request however much memory it wants (and the kernel is free to
deny its allocation), silence the allocation attempt with __GFP_NOWARN
in case it fails.

Reported-by: syzbot+76e7efc4748495855a4d@syzkaller.appspotmail.com
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/staging/android/ion/ion_system_heap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/staging/android/ion/ion_system_heap.c
+++ b/drivers/staging/android/ion/ion_system_heap.c
@@ -371,7 +371,7 @@ static int ion_system_contig_heap_alloca
 	unsigned long i;
 	int ret;
 
-	page = alloc_pages(low_order_gfp_flags, order);
+	page = alloc_pages(low_order_gfp_flags | __GFP_NOWARN, order);
 	if (!page)
 		return -ENOMEM;
 


Patches currently in stable-queue which might be from labbott@redhat.com are

queue-4.15/staging-android-ion-switch-from-warn-to-pr_warn.patch
queue-4.15/staging-android-ion-add-__gfp_nowarn-for-system-contig-heap.patch