================================================================== BUG: KASAN: slab-out-of-bounds in find_first_bit+0xf7/0x100 lib/find_bit.c:107 Read of size 8 at addr ffff8801d710a090 by task syz-executor6/7008 CPU: 0 PID: 7008 Comm: syz-executor6 Not tainted 4.18.0-rc3-next-20180706+ #1 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 __kernel_write+0x10c/0x370 fs/read_write.c:506 write_pipe_buf+0x181/0x240 fs/splice.c:798 splice_from_pipe_feed fs/splice.c:503 [inline] __splice_from_pipe+0x38e/0x7c0 fs/splice.c:627 splice_from_pipe+0x1ea/0x340 fs/splice.c:662 default_file_splice_write+0x3c/0x90 fs/splice.c:810 do_splice_from fs/splice.c:852 [inline] direct_splice_actor+0x128/0x190 fs/splice.c:1019 splice_direct_to_actor+0x318/0x8f0 fs/splice.c:974 do_splice_direct+0x2d4/0x420 fs/splice.c:1062 do_sendfile+0x62a/0xe20 fs/read_write.c:1440 __do_sys_sendfile64 fs/read_write.c:1495 [inline] __se_sys_sendfile64 fs/read_write.c:1487 [inline] __x64_sys_sendfile64+0x15d/0x250 fs/read_write.c:1487 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:00007f7007650c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007f70076516d4 RCX: 0000000000455e29 RDX: 0000000020000040 RSI: 0000000000000014 RDI: 0000000000000014 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004c1113 R14: 00000000004d1540 R15: 0000000000000000 Allocated by task 4487: 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] kvzalloc include/linux/mm.h:565 [inline] memcg_alloc_shrinker_maps mm/memcontrol.c:386 [inline] mem_cgroup_css_online+0x169/0x3c0 mm/memcontrol.c:4685 online_css+0x10c/0x350 kernel/cgroup/cgroup.c:4768 css_create kernel/cgroup/cgroup.c:4839 [inline] cgroup_apply_control_enable+0x777/0xe90 kernel/cgroup/cgroup.c:2987 cgroup_mkdir+0x88a/0x1170 kernel/cgroup/cgroup.c:5029 kernfs_iop_mkdir+0x159/0x1e0 fs/kernfs/dir.c:1099 vfs_mkdir+0x42e/0x6b0 fs/namei.c:3874 do_mkdirat+0x27b/0x310 fs/namei.c:3897 __do_sys_mkdir fs/namei.c:3913 [inline] __se_sys_mkdir fs/namei.c:3911 [inline] __x64_sys_mkdir+0x5c/0x80 fs/namei.c:3911 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 4481: 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 ksys_mount+0xa3/0x140 fs/namespace.c:3111 __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 The buggy address belongs to the object at ffff8801d710a080 which belongs to the cache kmalloc-32 of size 32 The buggy address is located 16 bytes inside of 32-byte region [ffff8801d710a080, ffff8801d710a0a0) The buggy address belongs to the page: page:ffffea00075c4280 count:1 mapcount:0 mapping:ffff8801da8001c0 index:0xffff8801d710afc1 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0007357688 ffffea00075c43c8 ffff8801da8001c0 raw: ffff8801d710afc1 ffff8801d710a000 000000010000003f 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d7109f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8801d710a000: 00 03 fc fc fc fc fc fc 00 07 fc fc fc fc fc fc >ffff8801d710a080: 00 00 05 fc fc fc fc fc 00 03 fc fc fc fc fc fc ^ ffff8801d710a100: 00 00 00 fc fc fc fc fc 00 00 01 fc fc fc fc fc ffff8801d710a180: 00 02 fc fc fc fc fc fc 00 02 fc fc fc fc fc fc ==================================================================