audit: type=1400 audit(1551089092.023:5): avc: denied { associate } for pid=2066 comm="syz-executor.0" name="syz0" scontext=unconfined_u:object_r:unlabeled_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=filesystem permissive=1 ================================================================== BUG: KASAN: use-after-free in perf_trace_filelock_lock+0x901/0x960 include/trace/events/filelock.h:61 Read of size 8 at addr ffff8801d8321a00 by task syz-executor.0/2934 CPU: 0 PID: 2934 Comm: syz-executor.0 Not tainted 4.9.155+ #27 ffff8801d71a7968 ffffffff81b47871 0000000000000000 ffffea000760c840 ffff8801d8321a00 0000000000000008 ffffffff81606c21 ffff8801d71a79a0 ffffffff81502825 0000000000000000 ffff8801d8321a00 ffff8801d8321a00 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [] print_address_description+0x6f/0x238 mm/kasan/report.c:256 [] kasan_report_error mm/kasan/report.c:355 [inline] [] kasan_report mm/kasan/report.c:412 [inline] [] kasan_report.cold+0x8c/0x2ba mm/kasan/report.c:397 [] __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 [] perf_trace_filelock_lock+0x901/0x960 include/trace/events/filelock.h:61 [] trace_posix_lock_inode include/trace/events/filelock.h:102 [inline] [] posix_lock_inode+0x1161/0x1aa0 fs/locks.c:1197 [] posix_lock_file fs/locks.c:1219 [inline] [] vfs_lock_file fs/locks.c:2173 [inline] [] vfs_lock_file+0x14f/0x1a0 fs/locks.c:2168 [] do_lock_file_wait.part.0+0xb4/0x1e0 fs/locks.c:2187 [] do_lock_file_wait fs/locks.c:2183 [inline] [] fcntl_setlk+0x2cb/0xc30 fs/locks.c:2284 [] do_fcntl fs/fcntl.c:288 [inline] [] SYSC_fcntl fs/fcntl.c:376 [inline] [] SyS_fcntl+0x579/0xb50 fs/fcntl.c:361 [] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Allocated by task 2934: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:505 [inline] set_track mm/kasan/kasan.c:517 [inline] kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:609 kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:594 kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:547 slab_post_alloc_hook mm/slab.h:417 [inline] slab_alloc_node mm/slub.c:2715 [inline] slab_alloc mm/slub.c:2723 [inline] kmem_cache_alloc+0xd5/0x2b0 mm/slub.c:2728 kmem_cache_zalloc include/linux/slab.h:626 [inline] locks_alloc_lock+0x1d/0x170 fs/locks.c:295 posix_lock_inode+0x48c/0x1aa0 fs/locks.c:1012 posix_lock_file fs/locks.c:1219 [inline] vfs_lock_file fs/locks.c:2173 [inline] vfs_lock_file+0x14f/0x1a0 fs/locks.c:2168 do_lock_file_wait.part.0+0xb4/0x1e0 fs/locks.c:2187 do_lock_file_wait fs/locks.c:2183 [inline] fcntl_setlk+0x2cb/0xc30 fs/locks.c:2284 do_fcntl fs/fcntl.c:288 [inline] SYSC_fcntl fs/fcntl.c:376 [inline] SyS_fcntl+0x579/0xb50 fs/fcntl.c:361 do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb Freed by task 2933: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57 save_stack mm/kasan/kasan.c:505 [inline] set_track mm/kasan/kasan.c:517 [inline] kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:582 slab_free_hook mm/slub.c:1355 [inline] slab_free_freelist_hook mm/slub.c:1377 [inline] slab_free mm/slub.c:2958 [inline] kmem_cache_free+0xbe/0x310 mm/slub.c:2980 locks_free_lock+0xea/0x140 fs/locks.c:331 locks_dispose_list+0x117/0x1e0 fs/locks.c:343 posix_lock_inode+0x369/0x1aa0 fs/locks.c:1196 posix_lock_file fs/locks.c:1219 [inline] vfs_lock_file fs/locks.c:2173 [inline] vfs_lock_file+0x14f/0x1a0 fs/locks.c:2168 locks_remove_posix+0x1e4/0x500 fs/locks.c:2490 filp_close+0xf4/0x140 fs/open.c:1133 __close_fd+0x15d/0x240 fs/file.c:651 SYSC_close fs/open.c:1148 [inline] SyS_close+0x46/0xa0 fs/open.c:1146 do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 entry_SYSCALL_64_after_swapgs+0x5d/0xdb The buggy address belongs to the object at ffff8801d8321a00 which belongs to the cache file_lock_cache of size 256 The buggy address is located 0 bytes inside of 256-byte region [ffff8801d8321a00, ffff8801d8321b00) The buggy address belongs to the page: page:ffffea000760c840 count:1 mapcount:0 mapping: (null) index:0x0 flags: 0x4000000000000080(slab) page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d8321900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d8321980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff8801d8321a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801d8321a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d8321b00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ==================================================================