================================================================== BUG: KASAN: slab-out-of-bounds in find_first_bit+0xf7/0x100 lib/find_bit.c:107 Read of size 8 at addr ffff8801d6c16b10 by task syz-executor7/15299 CPU: 1 PID: 15299 Comm: syz-executor7 Not tainted 4.18.0-rc3-next-20180709+ #2 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+0x1c9/0x2b4 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 find_first_bit+0xf7/0x100 lib/find_bit.c:107 shrink_slab_memcg mm/vmscan.c:580 [inline] shrink_slab+0x5d0/0xdb0 mm/vmscan.c:672 shrink_node+0x429/0x16a0 mm/vmscan.c:2736 shrink_zones mm/vmscan.c:2965 [inline] do_try_to_free_pages+0x3e7/0x1290 mm/vmscan.c:3027 try_to_free_mem_cgroup_pages+0x49d/0xc90 mm/vmscan.c:3325 memory_high_write+0x283/0x310 mm/memcontrol.c:5597 cgroup_file_write+0x31f/0x840 kernel/cgroup/cgroup.c:3500 kernfs_fop_write+0x2ba/0x480 fs/kernfs/file.c:316 __vfs_write+0x117/0x9f0 fs/read_write.c:485 vfs_write+0x1fc/0x560 fs/read_write.c:549 ksys_write+0x101/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455e29 Code: 1d ba 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 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb8c1068c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fb8c10696d4 RCX: 0000000000455e29 RDX: 0000000000000001 RSI: 0000000020000080 RDI: 0000000000000015 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004c2e77 R14: 00000000004d4c60 R15: 0000000000000000 Allocated by task 7710: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 __do_kmalloc_node mm/slab.c:3682 [inline] __kmalloc_node+0x47/0x70 mm/slab.c:3689 kmalloc_node include/linux/slab.h:555 [inline] kvmalloc_node+0x65/0xf0 mm/util.c:423 kvmalloc include/linux/mm.h:557 [inline] memcg_expand_one_shrinker_map mm/memcontrol.c:341 [inline] memcg_expand_shrinker_maps+0x1b1/0x3c0 mm/memcontrol.c:416 prealloc_memcg_shrinker mm/vmscan.c:185 [inline] prealloc_shrinker+0x29e/0x450 mm/vmscan.c:366 alloc_super+0x8dd/0xb10 fs/super.c:264 sget_userns+0x276/0x860 fs/super.c:615 sget+0x10b/0x150 fs/super.c:667 v9fs_mount+0xe2/0x900 fs/9p/vfs_super.c:141 legacy_get_tree+0x118/0x440 fs/fs_context.c:659 vfs_get_tree+0x1cb/0x5c0 fs/super.c:1751 do_new_mount fs/namespace.c:2567 [inline] do_mount+0x6c1/0x1fb0 fs/namespace.c:2889 ksys_mount+0x12d/0x140 fs/namespace.c:3105 __do_sys_mount fs/namespace.c:3119 [inline] __se_sys_mount fs/namespace.c:3116 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3116 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 4492: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kfree+0xd9/0x260 mm/slab.c:3813 __memcg_destroy_list_lru_node mm/list_lru.c:324 [inline] memcg_destroy_list_lru_node.isra.9+0xaf/0x100 mm/list_lru.c:375 memcg_destroy_list_lru mm/list_lru.c:463 [inline] list_lru_destroy+0x2ac/0x500 mm/list_lru.c:635 deactivate_locked_super+0xa3/0x100 fs/super.c:335 deactivate_super+0x2bb/0x320 fs/super.c:359 cleanup_mnt+0xbf/0x160 fs/namespace.c:1044 __cleanup_mnt+0x16/0x20 fs/namespace.c:1051 task_work_run+0x1ec/0x2a0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:192 [inline] exit_to_usermode_loop+0x313/0x370 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801d6c16b00 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 16 bytes inside of 32-byte region [ffff8801d6c16b00, ffff8801d6c16b20) The buggy address belongs to the page: page:ffffea00075b0580 count:1 mapcount:0 mapping:ffff8801da8001c0 index:0xffff8801d6c16fc1 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea00075d6208 ffffea0007387ac8 ffff8801da8001c0 raw: ffff8801d6c16fc1 ffff8801d6c16000 000000010000003f 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d6c16a00: 00 00 06 fc fc fc fc fc 00 00 06 fc fc fc fc fc ffff8801d6c16a80: fb fb fb fb fc fc fc fc 00 00 06 fc fc fc fc fc >ffff8801d6c16b00: 00 00 06 fc fc fc fc fc 00 05 fc fc fc fc fc fc ^ ffff8801d6c16b80: 00 00 05 fc fc fc fc fc 00 00 06 fc fc fc fc fc ffff8801d6c16c00: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc ==================================================================