RDX: 0000000000000065 RSI: 0000000000000084 RDI: 0000000000000014 RBP: 000000000000039b R08: 0000000000000010 R09: 0000000000000000 R10: 0000000020012000 R11: 0000000000000212 R12: 00000000006f2728 R13: 00000000ffffffff R14: 00007f9a584af6d4 R15: 0000000000000000 ================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:183 [inline] BUG: KASAN: use-after-free in atomic_read arch/x86/include/asm/atomic.h:27 [inline] BUG: KASAN: use-after-free in refcount_inc_not_zero+0x16e/0x180 lib/refcount.c:120 Read of size 4 at addr ffff8801c1550ec0 by task syz-executor6/3398 CPU: 1 PID: 3398 Comm: syz-executor6 Not tainted 4.15.0-rc4-next-20171221+ #78 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x25b/0x340 mm/kasan/report.c:409 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429 __read_once_size include/linux/compiler.h:183 [inline] atomic_read arch/x86/include/asm/atomic.h:27 [inline] refcount_inc_not_zero+0x16e/0x180 lib/refcount.c:120 refcount_inc+0x15/0x50 lib/refcount.c:153 get_ipc_ns include/linux/ipc_namespace.h:129 [inline] __get_ns_from_inode ipc/mqueue.c:110 [inline] get_ns_from_inode ipc/mqueue.c:118 [inline] mqueue_evict_inode+0x137/0x9c0 ipc/mqueue.c:402 evict+0x481/0x920 fs/inode.c:552 iput_final fs/inode.c:1514 [inline] iput+0x7b9/0xaf0 fs/inode.c:1541 dentry_unlink_inode+0x4b0/0x5e0 fs/dcache.c:375 __dentry_kill+0x3b7/0x6d0 fs/dcache.c:572 shrink_dentry_list+0x3c5/0xcf0 fs/dcache.c:1019 shrink_dcache_parent+0xba/0x230 fs/dcache.c:1453 do_one_tree+0x15/0x50 fs/dcache.c:1484 shrink_dcache_for_umount+0xbb/0x290 fs/dcache.c:1501 generic_shutdown_super+0xcd/0x540 fs/super.c:424 kill_anon_super fs/super.c:991 [inline] kill_litter_super+0x72/0x90 fs/super.c:1001 deactivate_locked_super+0x88/0xd0 fs/super.c:312 deactivate_super+0x141/0x1b0 fs/super.c:343 cleanup_mnt+0xb2/0x150 fs/namespace.c:1173 __cleanup_mnt+0x16/0x20 fs/namespace.c:1180 task_work_run+0x199/0x270 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9bb/0x1ad0 kernel/exit.c:869 do_group_exit+0x149/0x400 kernel/exit.c:972 get_signal+0x73f/0x16c0 kernel/signal.c:2337 do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:161 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264 entry_SYSCALL_64_fastpath+0x94/0x96 RIP: 0033:0x452ac9 RSP: 002b:00007f2804be8c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffea RBX: 000000000071bea0 RCX: 0000000000452ac9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000028060400 RBP: 00000000000005d3 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f5c68 R13: 00000000ffffffff R14: 00007f2804be96d4 R15: 0000000000000000 Allocated by task 3398: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3611 kmalloc include/linux/slab.h:516 [inline] create_ipc_ns ipc/namespace.c:45 [inline] copy_ipcs+0x1b3/0x520 ipc/namespace.c:96 create_new_namespaces+0x278/0x880 kernel/nsproxy.c:87 unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:206 SYSC_unshare kernel/fork.c:2414 [inline] SyS_unshare+0x653/0xfa0 kernel/fork.c:2364 entry_SYSCALL_64_fastpath+0x1f/0x96 Freed by task 3398: save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3489 [inline] kfree+0xd6/0x260 mm/slab.c:3804 free_ipc_ns ipc/namespace.c:139 [inline] put_ipc_ns+0x112/0x150 ipc/namespace.c:164 free_nsproxy+0xc0/0x1f0 kernel/nsproxy.c:180 switch_task_namespaces+0x9d/0xc0 kernel/nsproxy.c:229 exit_task_namespaces+0x17/0x20 kernel/nsproxy.c:234 do_exit+0x9b6/0x1ad0 kernel/exit.c:868 do_group_exit+0x149/0x400 kernel/exit.c:972 get_signal+0x73f/0x16c0 kernel/signal.c:2337 do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:161 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264 entry_SYSCALL_64_fastpath+0x94/0x96 The buggy address belongs to the object at ffff8801c1550ec0 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 0 bytes inside of 2048-byte region [ffff8801c1550ec0, ffff8801c15516c0) The buggy address belongs to the page: page:0000000076e02623 count:1 mapcount:0 mapping:00000000c1606be4 index:0x0 compound_mapcount: 0 flags: 0x2fffc0000008100(slab|head) raw: 02fffc0000008100 ffff8801c1550640 0000000000000000 0000000100000003 raw: ffffea0007057e20 ffffea0007053f20 ffff8801dac00c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801c1550d80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8801c1550e00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc >ffff8801c1550e80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ^ ffff8801c1550f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801c1550f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================