Hello, syzbot found the following crash on: HEAD commit: c11d28ab Add linux-next specific files for 20200522 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=14f54441100000 kernel config: https://syzkaller.appspot.com/x/.config?x=3f6dbdea4159fb66 dashboard link: https://syzkaller.appspot.com/bug?extid=20458a5eab138777efc9 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133e254a100000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15dbf016100000 The bug was bisected to: commit 4ef12f7198023c09ad6d25b652bd8748c965c7fa Author: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> Date: Wed May 13 15:18:40 2020 +0000 kobject: Make sure the parent does not get released before its children bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16763f06100000 final crash: https://syzkaller.appspot.com/x/report.txt?x=15763f06100000 console output: https://syzkaller.appspot.com/x/log.txt?x=11763f06100000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+20458a5eab138777efc9@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 4ef12f719802 ("kobject: Make sure the parent does not get released before its children") input: syz1 as /devices/virtual/input/input5 ================================================================== BUG: KASAN: use-after-free in __mutex_lock_common kernel/locking/mutex.c:938 [inline] BUG: KASAN: use-after-free in __mutex_lock+0x1033/0x13c0 kernel/locking/mutex.c:1103 Read of size 8 at addr ffff8880a019f158 by task syz-executor054/6791 CPU: 0 PID: 6791 Comm: syz-executor054 Not tainted 5.7.0-rc6-next-20200522-syzkaller #0 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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 __mutex_lock_common kernel/locking/mutex.c:938 [inline] __mutex_lock+0x1033/0x13c0 kernel/locking/mutex.c:1103 evdev_mark_dead drivers/input/evdev.c:1314 [inline] evdev_cleanup+0x21/0x190 drivers/input/evdev.c:1323 evdev_disconnect+0x45/0xb0 drivers/input/evdev.c:1408 __input_unregister_device+0x1b0/0x430 drivers/input/input.c:2091 input_unregister_device+0xb4/0xf0 drivers/input/input.c:2273 uinput_destroy_device+0x1e2/0x240 drivers/input/misc/uinput.c:298 uinput_release+0x37/0x50 drivers/input/misc/uinput.c:710 __fput+0x33e/0x880 fs/file_table.c:281 task_work_run+0xf4/0x1b0 kernel/task_work.c:123 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xb5e/0x2e10 kernel/exit.c:805 do_group_exit+0x125/0x340 kernel/exit.c:903 __do_sys_exit_group kernel/exit.c:914 [inline] __se_sys_exit_group kernel/exit.c:912 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:912 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x43f9e8 Code: Bad RIP value. RSP: 002b:00007ffd043eeff8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043f9e8 RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00000000004bf228 R08: 00000000000000e7 R09: ffffffffffffffd0 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006d1180 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 6791: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc mm/kasan/common.c:494 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:467 kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] evdev_connect+0x80/0x4d0 drivers/input/evdev.c:1352 input_attach_handler+0x194/0x200 drivers/input/input.c:1031 input_register_device.cold+0xf5/0x246 drivers/input/input.c:2229 uinput_create_device drivers/input/misc/uinput.c:364 [inline] uinput_ioctl_handler.isra.0+0x1210/0x1d80 drivers/input/misc/uinput.c:870 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Freed by task 6791: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] kasan_set_free_info mm/kasan/common.c:316 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:455 __cache_free mm/slab.c:3426 [inline] kfree+0x109/0x2b0 mm/slab.c:3757 device_release+0x71/0x200 drivers/base/core.c:1541 kobject_cleanup lib/kobject.c:701 [inline] kobject_release lib/kobject.c:732 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1c8/0x2f0 lib/kobject.c:749 cdev_device_del+0x69/0x80 fs/char_dev.c:575 evdev_disconnect+0x3d/0xb0 drivers/input/evdev.c:1407 __input_unregister_device+0x1b0/0x430 drivers/input/input.c:2091 input_unregister_device+0xb4/0xf0 drivers/input/input.c:2273 uinput_destroy_device+0x1e2/0x240 drivers/input/misc/uinput.c:298 uinput_release+0x37/0x50 drivers/input/misc/uinput.c:710 __fput+0x33e/0x880 fs/file_table.c:281 task_work_run+0xf4/0x1b0 kernel/task_work.c:123 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xb5e/0x2e10 kernel/exit.c:805 do_group_exit+0x125/0x340 kernel/exit.c:903 __do_sys_exit_group kernel/exit.c:914 [inline] __se_sys_exit_group kernel/exit.c:912 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:912 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 The buggy address belongs to the object at ffff8880a019f000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 344 bytes inside of 2048-byte region [ffff8880a019f000, ffff8880a019f800) The buggy address belongs to the page: page:ffffea00028067c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00029b4348 ffff8880aa001950 ffff8880aa000e00 raw: 0000000000000000 ffff8880a019f000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880a019f000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a019f080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880a019f100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880a019f180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880a019f200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches
