================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:197 [inline] BUG: KASAN: use-after-free in task_css include/linux/cgroup.h:480 [inline] BUG: KASAN: use-after-free in mem_cgroup_from_task mm/memcontrol.c:822 [inline] BUG: KASAN: use-after-free in get_mem_cgroup_from_mm mm/memcontrol.c:851 [inline] BUG: KASAN: use-after-free in get_mem_cgroup_from_mm+0x28f/0x2b0 mm/memcontrol.c:834 Read of size 8 at addr ffff88804f3e5718 by task syz-executor.2/2758 CPU: 0 PID: 2758 Comm: syz-executor.2 Not tainted 5.0.0-next-20190306 #4 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+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 __read_once_size include/linux/compiler.h:197 [inline] task_css include/linux/cgroup.h:480 [inline] mem_cgroup_from_task mm/memcontrol.c:822 [inline] get_mem_cgroup_from_mm mm/memcontrol.c:851 [inline] get_mem_cgroup_from_mm+0x28f/0x2b0 mm/memcontrol.c:834 mem_cgroup_try_charge+0x238/0x5e0 mm/memcontrol.c:5935 mcopy_atomic_pte mm/userfaultfd.c:71 [inline] mfill_atomic_pte mm/userfaultfd.c:418 [inline] __mcopy_atomic mm/userfaultfd.c:559 [inline] mcopy_atomic+0x893/0x2600 mm/userfaultfd.c:609 userfaultfd_copy fs/userfaultfd.c:1713 [inline] userfaultfd_ioctl+0x4d8/0x3aa0 fs/userfaultfd.c:1859 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696 ksys_ioctl+0xab/0xd0 fs/ioctl.c:713 __do_sys_ioctl fs/ioctl.c:720 [inline] __se_sys_ioctl fs/ioctl.c:718 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457f29 Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f6af2585c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457f29 RDX: 0000000020000100 RSI: 00000000c028aa03 RDI: 0000000000000005 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6af25866d4 R13: 00000000004c250a R14: 00000000004d4f38 R15: 00000000ffffffff Allocated by task 2766: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_kmalloc mm/kasan/common.c:497 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:505 slab_post_alloc_hook mm/slab.h:436 [inline] slab_alloc_node mm/slab.c:3335 [inline] kmem_cache_alloc_node+0x131/0x710 mm/slab.c:3645 alloc_task_struct_node kernel/fork.c:157 [inline] dup_task_struct kernel/fork.c:844 [inline] copy_process.part.0+0x1d35/0x79d0 kernel/fork.c:1753 copy_process kernel/fork.c:1710 [inline] _do_fork+0x257/0xfd0 kernel/fork.c:2227 __do_sys_clone kernel/fork.c:2334 [inline] __se_sys_clone kernel/fork.c:2328 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2328 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 2766: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467 __cache_free mm/slab.c:3498 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3764 free_task_struct kernel/fork.c:162 [inline] free_task+0xdd/0x120 kernel/fork.c:457 copy_process.part.0+0x1a67/0x79d0 kernel/fork.c:2159 copy_process kernel/fork.c:1710 [inline] _do_fork+0x257/0xfd0 kernel/fork.c:2227 __do_sys_clone kernel/fork.c:2334 [inline] __se_sys_clone kernel/fork.c:2328 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2328 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88804f3e4640 which belongs to the cache task_struct(49:syz2) of size 6080 The buggy address is located 4312 bytes inside of 6080-byte region [ffff88804f3e4640, ffff88804f3e5e00) The buggy address belongs to the page: page:ffffea00013cf900 count:1 mapcount:0 mapping:ffff8880a438fe00 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea000128e408 ffffea00012dc888 ffff8880a438fe00 raw: 0000000000000000 ffff88804f3e4640 0000000100000001 ffff8880569f46c0 page dumped because: kasan: bad access detected page->mem_cgroup:ffff8880569f46c0 Memory state around the buggy address: ffff88804f3e5600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804f3e5680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88804f3e5700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88804f3e5780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804f3e5800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================