================================================================== BUG: KASAN: use-after-free in css_task_iter_advance+0x49b/0x540 kernel/cgroup/cgroup.c:4507 Read of size 4 at addr ffff8880917df024 by task syz-executor.4/20192 CPU: 0 PID: 20192 Comm: syz-executor.4 Not tainted 5.2.0-rc3-next-20190604 #8 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 update_tasks_cpumask+0x8c/0x110 kernel/cgroup/cpuset.c:1017 update_cpumasks_hier+0x68f/0x1620 kernel/cgroup/cpuset.c:1397 update_cpumask kernel/cgroup/cpuset.c:1523 [inline] cpuset_write_resmask+0x132b/0x2030 kernel/cgroup/cpuset.c:2350 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:00007f9b5e214c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459279 RDX: 00000000000000e3 RSI: 0000000020000080 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9b5e2156d4 R13: 00000000004c8ed3 R14: 00000000004dfb98 R15: 00000000ffffffff Allocated by task 8960: 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] tomoyo_realpath_from_path+0xcd/0x7a0 security/tomoyo/realpath.c:277 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x230/0x430 security/tomoyo/file.c:822 tomoyo_inode_getattr+0x1d/0x30 security/tomoyo/tomoyo.c:129 security_inode_getattr+0xf2/0x150 security/security.c:1179 vfs_getattr+0x25/0x70 fs/stat.c:115 vfs_statx+0x157/0x200 fs/stat.c:191 vfs_stat include/linux/fs.h:3192 [inline] __do_sys_newstat+0xa4/0x130 fs/stat.c:341 __se_sys_newstat fs/stat.c:337 [inline] __x64_sys_newstat+0x54/0x80 fs/stat.c:337 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 8960: save_stack+0x23/0x90 mm/kasan/common.c:71 set_track mm/kasan/common.c:79 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459 __cache_free mm/slab.c:3426 [inline] kfree+0x106/0x2a0 mm/slab.c:3753 tomoyo_realpath_from_path+0x1de/0x7a0 security/tomoyo/realpath.c:319 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x230/0x430 security/tomoyo/file.c:822 tomoyo_inode_getattr+0x1d/0x30 security/tomoyo/tomoyo.c:129 security_inode_getattr+0xf2/0x150 security/security.c:1179 vfs_getattr+0x25/0x70 fs/stat.c:115 vfs_statx+0x157/0x200 fs/stat.c:191 vfs_stat include/linux/fs.h:3192 [inline] __do_sys_newstat+0xa4/0x130 fs/stat.c:341 __se_sys_newstat fs/stat.c:337 [inline] __x64_sys_newstat+0x54/0x80 fs/stat.c:337 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8880917de900 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 1828 bytes inside of 4096-byte region [ffff8880917de900, ffff8880917df900) The buggy address belongs to the page: page:ffffea000245f780 refcount:1 mapcount:0 mapping:ffff8880aa400dc0 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0002559f08 ffffea0002590688 ffff8880aa400dc0 raw: 0000000000000000 ffff8880917de900 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880917def00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880917def80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880917df000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880917df080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880917df100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================