RBP: 000000000072bea0 R08: 00000000200001c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000013 R13: 00000000004c248a R14: 00000000004d0058 R15: 0000000000000026 proc_fill_super: get root inode failed ================================================================== BUG: KASAN: use-after-free in fast_dput fs/dcache.c:717 [inline] BUG: KASAN: use-after-free in dput.part.26+0x634/0x7a0 fs/dcache.c:836 Read of size 4 at addr ffff8801b61f9e00 by task syz-executor7/9487 CPU: 0 PID: 9487 Comm: syz-executor7 Not tainted 4.18.0-rc4-next-20180712+ #5 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_load4_noabort+0x14/0x20 mm/kasan/report.c:432 fast_dput fs/dcache.c:717 [inline] dput.part.26+0x634/0x7a0 fs/dcache.c:836 dput+0x15/0x20 fs/dcache.c:831 proc_kill_sb+0x125/0x1e0 fs/proc/root.c:198 deactivate_locked_super+0x97/0x100 fs/super.c:328 vfs_get_super+0x20f/0x270 fs/super.c:1262 proc_get_tree+0x88/0xb0 fs/proc/root.c:159 vfs_get_tree+0x1cb/0x5c0 fs/super.c:1743 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 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:00007f94111afc68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f94111b06d4 RCX: 0000000000455e29 RDX: 0000000020000140 RSI: 0000000020000040 RDI: 0000000020000000 RBP: 000000000072bea0 R08: 00000000200001c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000013 R13: 00000000004c248a R14: 00000000004d0058 R15: 0000000000000026 Allocated by task 9454: 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 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554 __d_alloc+0xc8/0xd50 fs/dcache.c:1617 d_alloc+0x96/0x380 fs/dcache.c:1701 d_alloc_name+0xbb/0x120 fs/dcache.c:1755 proc_setup_self+0xe1/0x3af fs/proc/self.c:43 proc_fill_super+0x37e/0x630 fs/proc/root.c:133 vfs_get_super+0x15e/0x270 fs/super.c:1260 proc_get_tree+0x88/0xb0 fs/proc/root.c:159 vfs_get_tree+0x1cb/0x5c0 fs/super.c:1743 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 9484: 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] kmem_cache_free+0x86/0x2d0 mm/slab.c:3756 __d_free+0x20/0x30 fs/dcache.c:257 __rcu_reclaim kernel/rcu/rcu.h:258 [inline] rcu_do_batch kernel/rcu/tree.c:2576 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2878 [inline] __rcu_process_callbacks kernel/rcu/tree.c:2845 [inline] rcu_process_callbacks+0xe01/0x2810 kernel/rcu/tree.c:2862 __do_softirq+0x2e8/0xb17 kernel/softirq.c:288 The buggy address belongs to the object at ffff8801b61f9e00 which belongs to the cache dentry(17:syz7) of size 288 The buggy address is located 0 bytes inside of 288-byte region [ffff8801b61f9e00, ffff8801b61f9f20) The buggy address belongs to the page: page:ffffea0006d87e40 count:1 mapcount:0 mapping:ffff8801ccdf1380 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0006d88748 ffffea0006adecc8 ffff8801ccdf1380 raw: 0000000000000000 ffff8801b61f9040 000000010000000b ffff8801aeb54e40 page dumped because: kasan: bad access detected page->mem_cgroup:ffff8801aeb54e40 Memory state around the buggy address: ffff8801b61f9d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b61f9d80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff8801b61f9e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801b61f9e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801b61f9f00: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================