input: syz1 as /devices/virtual/input/input233 input: syz1 as /devices/virtual/input/input234 input: syz1 as /devices/virtual/input/input235 ================================================================== BUG: KASAN: use-after-free in cdev_put.part.0+0x4c/0x50 fs/char_dev.c:373 Read of size 8 at addr ffff8880a721aaa8 by task syz-executor695/7930 CPU: 0 PID: 7930 Comm: syz-executor695 Not tainted 4.14.157-syzkaller #0 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+0x142/0x197 lib/dump_stack.c:58 print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report mm/kasan/report.c:409 [inline] kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430 cdev_put.part.0+0x4c/0x50 fs/char_dev.c:373 cdev_put fs/char_dev.c:372 [inline] chrdev_open+0x266/0x590 fs/char_dev.c:431 do_dentry_open+0x73b/0xeb0 fs/open.c:777 input: syz1 as /devices/virtual/input/input236 vfs_open+0x105/0x220 fs/open.c:891 do_last fs/namei.c:3425 [inline] path_openat+0x8bd/0x3f70 fs/namei.c:3566 do_filp_open+0x18e/0x250 fs/namei.c:3600 do_sys_open+0x2c5/0x430 fs/open.c:1084 kobject: 'event6' (ffff88809c05e3f8): kobject_add_internal: parent: 'input233', set: 'devices' SYSC_open fs/open.c:1102 [inline] SyS_open+0x2d/0x40 fs/open.c:1097 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x405831 RSP: 002b:00007fabde6f6960 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000405831 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fabde6f6970 RBP: 6666666666666667 R08: 000000000000000f R09: 00007fabde6f7700 kobject: 'event6' (ffff88809c05e3f8): kobject_uevent_env R10: 00007fabde6f79d0 R11: 0000000000000293 R12: 00000000006dbc3c R13: 0000000000000000 R14: 0000000000000000 R15: 00000000317a7973 Allocated by task 7903: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc mm/kasan/kasan.c:551 [inline] kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529 kmem_cache_alloc_trace+0x152/0x790 mm/slab.c:3618 kmalloc include/linux/slab.h:488 [inline] kzalloc include/linux/slab.h:661 [inline] evdev_connect+0x76/0x4a0 drivers/input/evdev.c:1383 input_attach_handler+0x154/0x1a0 drivers/input/input.c:1004 input_register_device.cold+0xbf/0x202 drivers/input/input.c:2161 kobject: 'event6' (ffff88809c05e3f8): fill_kobj_path: path = '/devices/virtual/input/input233/event6' uinput_create_device drivers/input/misc/uinput.c:324 [inline] uinput_ioctl_handler.isra.0+0xdc8/0x18a0 drivers/input/misc/uinput.c:839 uinput_ioctl+0x4a/0x60 drivers/input/misc/uinput.c:1010 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Freed by task 7903: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x45/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kfree+0xcc/0x270 mm/slab.c:3815 evdev_free+0x5e/0x70 drivers/input/evdev.c:364 device_release+0x7b/0x1a0 drivers/base/core.c:821 kobject_cleanup lib/kobject.c:646 [inline] kobject_release lib/kobject.c:675 [inline] kref_put include/linux/kref.h:70 [inline] kobject_put.cold+0x269/0x2f9 lib/kobject.c:692 kobject: 'event5' (ffff88808d31b478): kobject_uevent_env put_device+0x20/0x30 drivers/base/core.c:2006 evdev_disconnect+0x8f/0xb0 drivers/input/evdev.c:1442 __input_unregister_device+0x1eb/0x480 drivers/input/input.c:2025 input_unregister_device+0xa9/0xf0 drivers/input/input.c:2205 uinput_destroy_device+0x1ce/0x220 drivers/input/misc/uinput.c:262 uinput_release+0x3c/0x60 drivers/input/misc/uinput.c:680 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x7df/0x2ce0 kernel/exit.c:874 do_group_exit+0x111/0x330 kernel/exit.c:977 get_signal+0x381/0x1cd0 kernel/signal.c:2413 do_signal+0x86/0x19a0 arch/x86/kernel/signal.c:814 kobject: 'event5' (ffff88808d31b478): fill_kobj_path: path = '/devices/virtual/input/input231/event5' exit_to_usermode_loop+0x15c/0x220 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 The buggy address belongs to the object at ffff8880a721a4c0 which belongs to the cache kmalloc-2048 of size 2048 The buggy address is located 1512 bytes inside of 2048-byte region [ffff8880a721a4c0, ffff8880a721acc0) The buggy address belongs to the page: page:ffffea00029c8680 count:1 mapcount:0 mapping:ffff8880a721a4c0 index:0x0 compound_mapcount: 0 flags: 0xfffe0000008100(slab|head) raw: 00fffe0000008100 ffff8880a721a4c0 0000000000000000 0000000100000003 raw: ffffea00021c05a0 ffffea00021d8aa0 ffff8880aa800c40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a721a980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a721aa00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a721aa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a721ab00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a721ab80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================