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Date:   Mon, 16 Sep 2019 16:31:34 -0400 (EDT)
From:   Alan Stern <stern@rowland.harvard.edu>
To:     syzbot <syzbot+e1d1a6e595adbd2458f1@syzkaller.appspotmail.com>
cc:     glider@google.com, <gregkh@linuxfoundation.org>,
        <kai.heng.feng@canonical.com>,
        Kernel development list <linux-kernel@vger.kernel.org>,
        USB list <linux-usb@vger.kernel.org>,
        <syzkaller-bugs@googlegroups.com>, <yuehaibing@huawei.com>
Subject: Re: KMSAN: uninit-value in usb_autopm_put_interface
In-Reply-To: <00000000000031432d0592b00f44@google.com>
Message-ID: <Pine.LNX.4.44L0.1909161628090.1489-100000@iolanthe.rowland.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, 16 Sep 2019, syzbot wrote:

> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    014077b5 DO-NOT-SUBMIT: usb-fuzzer: main usb gadget fuzzer..
> git tree:       https://github.com/google/kmsan.git master
> console output: https://syzkaller.appspot.com/x/log.txt?x=16a7dde1600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=f03c659d0830ab8d
> dashboard link: https://syzkaller.appspot.com/bug?extid=e1d1a6e595adbd2458f1
> compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
> 80fee25776c2fb61e74c1ecb1a523375c2500b69)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=176303e1600000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10e8f23e600000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+e1d1a6e595adbd2458f1@syzkaller.appspotmail.com
> 
> ==================================================================
> BUG: KMSAN: uninit-value in __write_once_size include/linux/compiler.h:235  
> [inline]
> BUG: KMSAN: uninit-value in pm_runtime_mark_last_busy  
> include/linux/pm_runtime.h:107 [inline]
> BUG: KMSAN: uninit-value in usb_mark_last_busy include/linux/usb.h:774  
> [inline]
> BUG: KMSAN: uninit-value in usb_autopm_put_interface+0xf2/0x120  
> drivers/usb/core/driver.c:1630
> CPU: 0 PID: 11318 Comm: syz-executor549 Not tainted 5.3.0-rc7+ #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+0x191/0x1f0 lib/dump_stack.c:113
>   kmsan_report+0x162/0x2d0 mm/kmsan/kmsan_report.c:109
>   __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294
>   __write_once_size include/linux/compiler.h:235 [inline]
>   pm_runtime_mark_last_busy include/linux/pm_runtime.h:107 [inline]
>   usb_mark_last_busy include/linux/usb.h:774 [inline]
>   usb_autopm_put_interface+0xf2/0x120 drivers/usb/core/driver.c:1630
>   usbhid_power+0x12a/0x170 drivers/hid/usbhid/hid-core.c:1238
>   hid_hw_power include/linux/hid.h:1038 [inline]
>   drop_ref drivers/hid/hidraw.c:338 [inline]
>   hidraw_release+0x4a9/0x6b0 drivers/hid/hidraw.c:356
>   __fput+0x4c9/0xba0 fs/file_table.c:280
>   ____fput+0x37/0x40 fs/file_table.c:313
>   task_work_run+0x22e/0x2a0 kernel/task_work.c:113
>   tracehook_notify_resume include/linux/tracehook.h:188 [inline]
>   exit_to_usermode_loop arch/x86/entry/common.c:163 [inline]
>   prepare_exit_to_usermode+0x39d/0x4d0 arch/x86/entry/common.c:194
>   syscall_return_slowpath+0x90/0x610 arch/x86/entry/common.c:274
>   do_syscall_64+0xe2/0xf0 arch/x86/entry/common.c:300
>   entry_SYSCALL_64_after_hwframe+0x63/0xe7
> RIP: 0033:0x401b20
> Code: 01 f0 ff ff 0f 83 c0 0b 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f  
> 44 00 00 83 3d ad 5b 2d 00 00 75 14 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff  
> ff 0f 83 94 0b 00 00 c3 48 83 ec 08 e8 fa 00 00 00
> RSP: 002b:00007ffc46217cb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
> RAX: ffffffffffffffea RBX: 0000000000000000 RCX: 0000000000401b20
> RDX: 0000000000000000 RSI: 000000000010503d RDI: 00007ffc46217cc0
> RBP: 6666666666666667 R08: 000000000000000f R09: 000000000000000b
> R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000402b40
> R13: 0000000000402bd0 R14: 0000000000000000 R15: 0000000000000000
> 
> Uninit was created at:
>   kmsan_save_stack_with_flags mm/kmsan/kmsan.c:189 [inline]
>   kmsan_internal_poison_shadow+0x58/0xb0 mm/kmsan/kmsan.c:148
>   kmsan_slab_free+0x8d/0x100 mm/kmsan/kmsan_hooks.c:195
>   slab_free_freelist_hook mm/slub.c:1472 [inline]
>   slab_free mm/slub.c:3038 [inline]
>   kfree+0x4c1/0x2db0 mm/slub.c:3980
>   usb_release_interface+0x105/0x120 drivers/usb/core/message.c:1633
>   device_release+0xe2/0x380 drivers/base/core.c:1060
>   kobject_cleanup lib/kobject.c:693 [inline]
>   kobject_release lib/kobject.c:722 [inline]
>   kref_put include/linux/kref.h:65 [inline]
>   kobject_put+0x38d/0x480 lib/kobject.c:739
>   put_device+0x51/0x70 drivers/base/core.c:2264
>   usb_disable_device+0x69a/0x1150 drivers/usb/core/message.c:1248
>   usb_disconnect+0x51e/0xd60 drivers/usb/core/hub.c:2199
>   hub_port_connect drivers/usb/core/hub.c:4949 [inline]
>   hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
>   port_event drivers/usb/core/hub.c:5359 [inline]
>   hub_event+0x3fd0/0x72f0 drivers/usb/core/hub.c:5441
>   process_one_work+0x1572/0x1ef0 kernel/workqueue.c:2269
>   worker_thread+0x111b/0x2460 kernel/workqueue.c:2415
>   kthread+0x4b5/0x4f0 kernel/kthread.c:256
>   ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355
> ==================================================================
> 
> 
> ---
> 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@googlegroups.com.
> 
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> syzbot can test patches for this bug, for details see:
> https://goo.gl/tpsmEJ#testing-patches

This is probably the same problem that was fixed in the Logitech driver
earlier.  The fix still appears to be in linux-next (commit
5f9242775bb6).

Shouldn't syzbot wait until after the merge window before running tests
like this?

Alan Stern