================================================================== BUG: KASAN: use-after-free in d_walk+0x86c/0x950 fs/dcache.c:1281 Read of size 8 at addr ffff888095e6add0 by task syz-executor.0/7708 CPU: 1 PID: 7708 Comm: syz-executor.0 Not tainted 5.0.0+ #97 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+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 d_walk+0x86c/0x950 fs/dcache.c:1281 shrink_dcache_parent+0xa4/0x140 fs/dcache.c:1496 d_invalidate fs/dcache.c:1590 [inline] d_invalidate+0xfb/0x230 fs/dcache.c:1575 proc_flush_task_mnt fs/proc/base.c:3069 [inline] proc_flush_task+0x28a/0x4d0 fs/proc/base.c:3139 release_task+0x18c/0x1620 kernel/exit.c:196 wait_task_zombie kernel/exit.c:1164 [inline] wait_consider_task+0x2c95/0x3910 kernel/exit.c:1391 do_wait_thread kernel/exit.c:1454 [inline] do_wait+0x439/0x9d0 kernel/exit.c:1525 kernel_wait4+0x171/0x290 kernel/exit.c:1667 __do_sys_wait4+0x147/0x160 kernel/exit.c:1679 __se_sys_wait4 kernel/exit.c:1675 [inline] __x64_sys_wait4+0x97/0xf0 kernel/exit.c:1675 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4120ba Code: 0f 83 1a 17 00 00 c3 66 0f 1f 84 00 00 00 00 00 8b 05 de 41 64 00 85 c0 75 36 45 31 d2 48 63 d2 48 63 ff b8 3d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 06 c3 0f 1f 44 00 00 48 c7 c2 d4 ff ff ff f7 RSP: 002b:00007ffe51c30ab8 EFLAGS: 00000246 ORIG_RAX: 000000000000003d RAX: ffffffffffffffda RBX: 0000000000031389 RCX: 00000000004120ba RDX: 0000000040000001 RSI: 00007ffe51c30af0 RDI: ffffffffffffffff RBP: 00000000000001cb R08: 0000000000000001 R09: 0000000001aa7940 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000009 R13: 00007ffe51c30af0 R14: 000000000003106c R15: 00007ffe51c30b00 Allocated by task 11550: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_kmalloc mm/kasan/common.c:495 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:468 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:503 slab_post_alloc_hook mm/slab.h:440 [inline] slab_alloc mm/slab.c:3388 [inline] kmem_cache_alloc+0x11a/0x6f0 mm/slab.c:3548 __d_alloc+0x2e/0x8c0 fs/dcache.c:1622 d_alloc_pseudo+0x1e/0x30 fs/dcache.c:1745 alloc_file_pseudo+0xe2/0x280 fs/file_table.c:224 sock_alloc_file+0x4d/0x170 net/socket.c:394 sock_map_fd net/socket.c:417 [inline] __sys_socket+0x150/0x220 net/socket.c:1372 __do_sys_socket net/socket.c:1377 [inline] __se_sys_socket net/socket.c:1375 [inline] __x64_sys_socket+0x73/0xb0 net/socket.c:1375 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 11539: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:457 kasan_slab_free+0xe/0x10 mm/kasan/common.c:465 __cache_free mm/slab.c:3494 [inline] kmem_cache_free+0x86/0x260 mm/slab.c:3754 __d_free fs/dcache.c:269 [inline] dentry_free+0xed/0x170 fs/dcache.c:348 __dentry_kill+0x45f/0x610 fs/dcache.c:593 dentry_kill+0xd7/0x5e0 fs/dcache.c:698 dput+0x570/0x6a0 fs/dcache.c:859 __fput+0x429/0x8d0 fs/file_table.c:291 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x273/0x2c0 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+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff888095e6ace0 which belongs to the cache dentry(17:syz0) of size 288 The buggy address is located 240 bytes inside of 288-byte region [ffff888095e6ace0, ffff888095e6ae00) The buggy address belongs to the page: page:ffffea0002579a80 count:1 mapcount:0 mapping:ffff888098f7be40 index:0x0 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea0002577cc8 ffffea000257df48 ffff888098f7be40 raw: 0000000000000000 ffff888095e6a080 000000010000000b ffff88806d9baec0 page dumped because: kasan: bad access detected page->mem_cgroup:ffff88806d9baec0 Memory state around the buggy address: ffff888095e6ac80: 00 00 00 00 fc fc fc fc fc fc fc fc fb fb fb fb ffff888095e6ad00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888095e6ad80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888095e6ae00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff888095e6ae80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================