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=13abef06100000 kernel config: https://syzkaller.appspot.com/x/.config?x=3f6dbdea4159fb66 dashboard link: https://syzkaller.appspot.com/bug?extid=2af7aca9f40c4c773068 compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+2af7aca9f40c4c773068@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in kobject_put+0x296/0x2f0 lib/kobject.c:745 Read of size 1 at addr ffff88808e2391c4 by task syz-executor.1/11174 CPU: 0 PID: 11174 Comm: syz-executor.1 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 kobject_put+0x296/0x2f0 lib/kobject.c:745 cdev_put.part.0+0x32/0x50 fs/char_dev.c:365 cdev_put+0x1b/0x30 fs/char_dev.c:363 __fput+0x69b/0x880 fs/file_table.c:284 task_work_run+0xf4/0x1b0 kernel/task_work.c:123 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x2fa/0x360 arch/x86/entry/common.c:165 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x6b1/0x7d0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x416621 Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007fff6b522200 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000416621 RDX: 0000000000000000 RSI: 00000000000000d0 RDI: 0000000000000004 RBP: 0000000000000001 R08: 00000000551800d0 R09: 00000000551800d4 R10: 00007fff6b5222f0 R11: 0000000000000293 R12: 0000000000792bd0 R13: 000000000004e9c2 R14: ffffffffffffffff R15: 000000000078bf0c Allocated by task 11177: 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 11174: 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 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_put.part.0+0x32/0x50 fs/char_dev.c:365 cdev_put+0x1b/0x30 fs/char_dev.c:363 __fput+0x69b/0x880 fs/file_table.c:284 task_work_run+0xf4/0x1b0 kernel/task_work.c:123 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x2fa/0x360 arch/x86/entry/common.c:165 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x6b1/0x7d0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x49/0xb3 The buggy address belongs to the object at ffff88808e239000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 452 bytes inside of 2048-byte region [ffff88808e239000, ffff88808e239800) The buggy address belongs to the page: page:ffffea0002388e40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 flags: 0xfffe0000000200(slab) raw: 00fffe0000000200 ffffea00029d3dc8 ffffea00027ec908 ffff8880aa000e00 raw: 0000000000000000 ffff88808e239000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808e239080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808e239100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88808e239180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808e239200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808e239280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This bug is generated by a bot. 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