================================================================== BUG: KASAN: slab-out-of-bounds in css_task_iter_advance+0x50e/0x540 kernel/cgroup/cgroup.c:4503 Read of size 8 at addr ffff8880860c9208 by task syz-executor906/8694 CPU: 1 PID: 8694 Comm: syz-executor906 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_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 css_task_iter_advance+0x50e/0x540 kernel/cgroup/cgroup.c:4503 css_task_iter_start+0x18b/0x230 kernel/cgroup/cgroup.c:4543 __cgroup_procs_start.isra.0+0x32f/0x400 kernel/cgroup/cgroup.c:4638 cgroup_procs_start kernel/cgroup/cgroup.c:4660 [inline] cgroup_procs_start+0x1e7/0x260 kernel/cgroup/cgroup.c:4647 cgroup_seqfile_start+0xa4/0xd0 kernel/cgroup/cgroup.c:3752 kernfs_seq_start+0xdc/0x190 fs/kernfs/file.c:118 seq_read+0x2a7/0x1110 fs/seq_file.c:224 kernfs_fop_read+0xed/0x560 fs/kernfs/file.c:252 do_loop_readv_writev fs/read_write.c:714 [inline] do_loop_readv_writev fs/read_write.c:701 [inline] do_iter_read+0x4a4/0x660 fs/read_write.c:935 vfs_readv+0xf0/0x160 fs/read_write.c:997 kernel_readv fs/splice.c:359 [inline] default_file_splice_read+0x475/0x890 fs/splice.c:414 do_splice_to+0x127/0x180 fs/splice.c:877 splice_direct_to_actor+0x2d2/0x970 fs/splice.c:954 do_splice_direct+0x1da/0x2a0 fs/splice.c:1063 do_sendfile+0x597/0xd00 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1525 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0x1dd/0x220 fs/read_write.c:1511 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x442409 Code: e8 8c b2 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 eb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffd293a8008 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000442409 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 0000000000000008 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 000000000000001c R13: 0000000000403210 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 8692: 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 kmem_cache_alloc_trace+0x151/0x750 mm/slab.c:3549 kmalloc include/linux/slab.h:547 [inline] kzalloc include/linux/slab.h:742 [inline] find_css_set+0x742/0x18b0 kernel/cgroup/cgroup.c:1203 cgroup_migrate_prepare_dst+0x104/0x780 kernel/cgroup/cgroup.c:2662 cgroup_update_dfl_csses+0x331/0x5a0 kernel/cgroup/cgroup.c:2911 cgroup_apply_control kernel/cgroup/cgroup.c:3165 [inline] cgroup_apply_control+0x3e/0x50 kernel/cgroup/cgroup.c:3150 cgroup_subtree_control_write+0x7f5/0xbd0 kernel/cgroup/cgroup.c:3314 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 Freed by task 8201: 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_supervisor+0x360/0xef0 security/tomoyo/common.c:2147 tomoyo_audit_env_log security/tomoyo/environ.c:36 [inline] tomoyo_env_perm+0x18e/0x210 security/tomoyo/environ.c:63 tomoyo_environ security/tomoyo/domain.c:670 [inline] tomoyo_find_next_domain+0x1354/0x1f6c security/tomoyo/domain.c:876 tomoyo_bprm_check_security security/tomoyo/tomoyo.c:107 [inline] tomoyo_bprm_check_security+0x124/0x1b0 security/tomoyo/tomoyo.c:97 security_bprm_check+0x63/0xb0 security/security.c:747 search_binary_handler+0x71/0x570 fs/exec.c:1645 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1310/0x22f0 fs/exec.c:1821 do_execveat_common fs/exec.c:1868 [inline] do_execve fs/exec.c:1885 [inline] __do_sys_execve fs/exec.c:1961 [inline] __se_sys_execve fs/exec.c:1956 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1956 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 ffff8880860c8dc0 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 72 bytes to the right of 1024-byte region [ffff8880860c8dc0, ffff8880860c91c0) The buggy address belongs to the page: page:ffffea0002183200 refcount:1 mapcount:0 mapping:ffff8880aa400ac0 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0002869d08 ffffea00022ed608 ffff8880aa400ac0 raw: 0000000000000000 ffff8880860c8040 0000000100000007 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880860c9100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880860c9180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880860c9200: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 ^ ffff8880860c9280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880860c9300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 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