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BUG: KASAN: slab-out-of-bounds in css_task_iter_advance+0x49b/0x540 kernel/cgroup/cgroup.c:4507
Read of size 4 at addr ffff88806895dd9c by task syz-executor.5/2864

CPU: 1 PID: 2864 Comm: syz-executor.5 Not tainted 5.2.0-rc3-next-20190607 #11
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351
 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131
 css_task_iter_advance+0x49b/0x540 kernel/cgroup/cgroup.c:4507
 css_task_iter_start+0x18b/0x230 kernel/cgroup/cgroup.c:4543
 mem_cgroup_scan_tasks+0xaf/0x180 mm/memcontrol.c:1167
 select_bad_process mm/oom_kill.c:374 [inline]
 out_of_memory mm/oom_kill.c:1088 [inline]
 out_of_memory+0x6b2/0x1280 mm/oom_kill.c:1035
 mem_cgroup_out_of_memory+0x1ca/0x230 mm/memcontrol.c:1573
 memory_max_write+0x256/0x3a0 mm/memcontrol.c:5726
 cgroup_file_write+0x241/0x790 kernel/cgroup/cgroup.c:3711
 kernfs_fop_write+0x2b8/0x480 fs/kernfs/file.c:316
 __vfs_write+0x8a/0x110 fs/read_write.c:494
 vfs_write+0x268/0x5d0 fs/read_write.c:558
 ksys_write+0x14f/0x290 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:620
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459279
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f852967fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459279
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f85296806d4
R13: 00000000004c911b R14: 00000000004e0098 R15: 00000000ffffffff

Allocated by task 8847:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc mm/kasan/common.c:489 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503
 __do_kmalloc mm/slab.c:3654 [inline]
 __kmalloc+0x15c/0x740 mm/slab.c:3663
 kmalloc include/linux/slab.h:552 [inline]
 kzalloc include/linux/slab.h:742 [inline]
 mem_cgroup_alloc mm/memcontrol.c:4654 [inline]
 mem_cgroup_css_alloc+0x59/0x17b0 mm/memcontrol.c:4709
 css_create kernel/cgroup/cgroup.c:5112 [inline]
 cgroup_apply_control_enable+0x44d/0xc40 kernel/cgroup/cgroup.c:3076
 cgroup_mkdir+0x8a3/0x1190 kernel/cgroup/cgroup.c:5349
 kernfs_iop_mkdir+0x14d/0x1d0 fs/kernfs/dir.c:1124
 vfs_mkdir+0x42e/0x670 fs/namei.c:3815
 do_mkdirat+0x234/0x2a0 fs/namei.c:3838
 __do_sys_mkdir fs/namei.c:3854 [inline]
 __se_sys_mkdir fs/namei.c:3852 [inline]
 __x64_sys_mkdir+0x5c/0x80 fs/namei.c:3852
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff88806895c480
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 2332 bytes to the right of
 4096-byte region [ffff88806895c480, ffff88806895d480)
The buggy address belongs to the page:
page:ffffea0001a25700 refcount:1 mapcount:0 mapping:ffff8880aa400dc0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00025dd188 ffffea0002564888 ffff8880aa400dc0
raw: 0000000000000000 ffff88806895c480 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88806895dc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88806895dd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88806895dd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                            ^
 ffff88806895de00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88806895de80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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