netlink: 8 bytes leftover after parsing attributes in process `syz-executor3'. ================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:193 [inline] BUG: KASAN: use-after-free in task_css include/linux/cgroup.h:479 [inline] BUG: KASAN: use-after-free in mem_cgroup_from_task mm/memcontrol.c:815 [inline] BUG: KASAN: use-after-free in get_mem_cgroup_from_mm mm/memcontrol.c:844 [inline] BUG: KASAN: use-after-free in get_mem_cgroup_from_mm+0x3d0/0x420 mm/memcontrol.c:827 Read of size 8 at addr ffff888082c652d0 by task syz-executor1/5455 CPU: 0 PID: 5455 Comm: syz-executor1 Not tainted 5.0.0-rc3+ #39 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+0x1db/0x2d0 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:135 __read_once_size include/linux/compiler.h:193 [inline] task_css include/linux/cgroup.h:479 [inline] mem_cgroup_from_task mm/memcontrol.c:815 [inline] get_mem_cgroup_from_mm mm/memcontrol.c:844 [inline] get_mem_cgroup_from_mm+0x3d0/0x420 mm/memcontrol.c:827 mem_cgroup_try_charge+0x41f/0xdb0 mm/memcontrol.c:5911 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+0xaa7/0x2c50 mm/userfaultfd.c:609 userfaultfd_copy fs/userfaultfd.c:1713 [inline] userfaultfd_ioctl+0x2481/0x54e0 fs/userfaultfd.c:1859 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:509 [inline] do_vfs_ioctl+0x107b/0x17d0 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+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458099 Code: 6d 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb78c38ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458099 RDX: 0000000020000100 RSI: 00000000c028aa03 RDI: 0000000000000004 RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb78c38f6d4 R13: 00000000004c2685 R14: 00000000004d4e70 R15: 00000000ffffffff Allocated by task 5448: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_kmalloc mm/kasan/common.c:496 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469 kasan_kmalloc mm/kasan/common.c:504 [inline] kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:411 kmem_cache_alloc_node+0x144/0x710 mm/slab.c:3633 alloc_task_struct_node kernel/fork.c:158 [inline] dup_task_struct kernel/fork.c:845 [inline] copy_process+0x405b/0x8710 kernel/fork.c:1753 _do_fork+0x1a9/0x1170 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+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 5448: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466 __cache_free mm/slab.c:3487 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3749 free_task_struct kernel/fork.c:163 [inline] free_task+0x170/0x1f0 kernel/fork.c:458 copy_process+0x10c8/0x8710 kernel/fork.c:2159 _do_fork+0x1a9/0x1170 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+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888082c64200 which belongs to the cache task_struct(33:syz1) of size 6080 The buggy address is located 4304 bytes inside of 6080-byte region [ffff888082c64200, ffff888082c659c0) The buggy address belongs to the page: page:ffffea00020b1900 count:1 mapcount:0 mapping:ffff88807ee8ee40 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0001a0f688 ffffea000264ed88 ffff88807ee8ee40 raw: 0000000000000000 ffff888082c64200 0000000100000001 ffff8880a8e1e140 page dumped because: kasan: bad access detected page->mem_cgroup:ffff8880a8e1e140 Memory state around the buggy address: ffff888082c65180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888082c65200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888082c65280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888082c65300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888082c65380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ------------[ cut here ]------------ downgrading a read lock WARNING: CPU: 1 PID: 5462 at kernel/locking/lockdep.c:3553 __lock_downgrade kernel/locking/lockdep.c:3553 [inline] WARNING: CPU: 1 PID: 5462 at kernel/locking/lockdep.c:3553 lock_downgrade+0x4d2/0x910 kernel/locking/lockdep.c:3816