Message-ID: <CAAeHK+ym+yAO2s_QL3j9ELwF=4b1TF_r5gwCFEEyLvKOcrhfGg@mail.gmail.com>
Date:   Fri, 20 Sep 2019 17:41:18 +0200
From:   Andrey Konovalov <andreyknvl@...gle.com>
To:     syzbot <syzbot+9a22af9cbb07280ce9cf@...kaller.appspotmail.com>
Cc:     baijiaju1990@...il.com, bigeasy@...utronix.de,
        Colin Ian King <colin.king@...onical.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        LKML <linux-kernel@...r.kernel.org>,
        USB list <linux-usb@...r.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@...glegroups.com>,
        yuehaibing@...wei.com
Subject: Re: KASAN: use-after-free Read in wdm_out_callback

On Mon, Aug 19, 2019 at 4:48 PM syzbot
<syzbot+9a22af9cbb07280ce9cf@...kaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    d0847550 usb-fuzzer: main usb gadget fuzzer driver
> git tree:       https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=136553ba600000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=dbc9c80cc095da19
> dashboard link: https://syzkaller.appspot.com/bug?extid=9a22af9cbb07280ce9cf
> 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+9a22af9cbb07280ce9cf@...kaller.appspotmail.com
>
> cdc_wdm 1-1:118.0: nonzero urb status received: -71
> cdc_wdm 1-1:118.0: wdm_int_callback - 0 bytes
> ==================================================================
> BUG: KASAN: use-after-free in __lock_acquire+0x302a/0x3b50
> kernel/locking/lockdep.c:3753
> Read of size 8 at addr ffff8881cbdca8e8 by task swapper/0/0
>
> CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc4+ #26
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
>   <IRQ>
>   __dump_stack lib/dump_stack.c:77 [inline]
>   dump_stack+0xca/0x13e lib/dump_stack.c:113
>   print_address_description+0x6a/0x32c mm/kasan/report.c:351
>   __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
>   kasan_report+0xe/0x12 mm/kasan/common.c:612
>   __lock_acquire+0x302a/0x3b50 kernel/locking/lockdep.c:3753
>   lock_acquire+0x127/0x320 kernel/locking/lockdep.c:4412
>   __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
>   _raw_spin_lock_irqsave+0x32/0x50 kernel/locking/spinlock.c:159
>   wdm_out_callback+0x45/0x170 drivers/usb/class/cdc-wdm.c:148
>   __usb_hcd_giveback_urb+0x1f2/0x470 drivers/usb/core/hcd.c:1657
>   usb_hcd_giveback_urb+0x368/0x420 drivers/usb/core/hcd.c:1722
>   dummy_timer+0x120f/0x2fa2 drivers/usb/gadget/udc/dummy_hcd.c:1965
>   call_timer_fn+0x179/0x650 kernel/time/timer.c:1322
>   expire_timers kernel/time/timer.c:1366 [inline]
>   __run_timers kernel/time/timer.c:1685 [inline]
>   __run_timers kernel/time/timer.c:1653 [inline]
>   run_timer_softirq+0x5cc/0x14b0 kernel/time/timer.c:1698
>   __do_softirq+0x221/0x912 kernel/softirq.c:292
>   invoke_softirq kernel/softirq.c:373 [inline]
>   irq_exit+0x178/0x1a0 kernel/softirq.c:413
>   exiting_irq arch/x86/include/asm/apic.h:537 [inline]
>   smp_apic_timer_interrupt+0x12f/0x500 arch/x86/kernel/apic/apic.c:1095
>   apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
>   </IRQ>
> RIP: 0010:default_idle+0x28/0x2e0 arch/x86/kernel/process.c:581
> Code: 90 90 41 56 41 55 65 44 8b 2d 64 ea 93 7a 41 54 55 53 0f 1f 44 00 00
> e8 96 5b d5 fb e9 07 00 00 00 0f 00 2d 7a 8f 54 00 fb f4 <65> 44 8b 2d 40
> ea 93 7a 0f 1f 44 00 00 5b 5d 41 5c 41 5d 41 5e c3
> RSP: 0018:ffffffff86c07da8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
> RAX: 0000000000000007 RBX: ffffffff86c2b200 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffffffff86c2ba44
> RBP: fffffbfff0d85640 R08: ffffffff86c2b200 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
>   cpuidle_idle_call kernel/sched/idle.c:154 [inline]
>   do_idle+0x3c2/0x4f0 kernel/sched/idle.c:263
>   cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:354
>   start_kernel+0x838/0x872 init/main.c:785
>   secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241
>
> Allocated by task 83:
>   save_stack+0x1b/0x80 mm/kasan/common.c:69
>   set_track mm/kasan/common.c:77 [inline]
>   __kasan_kmalloc mm/kasan/common.c:487 [inline]
>   __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:460
>   kmalloc include/linux/slab.h:552 [inline]
>   kzalloc include/linux/slab.h:748 [inline]
>   wdm_create+0x56/0x1720 drivers/usb/class/cdc-wdm.c:786
>   wdm_probe+0x220/0x2d0 drivers/usb/class/cdc-wdm.c:922
>   usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
>   really_probe+0x281/0x6d0 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2165
>   usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
>   generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
>   usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
>   really_probe+0x281/0x6d0 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2165
>   usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
>   hub_port_connect drivers/usb/core/hub.c:5098 [inline]
>   hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
>   port_event drivers/usb/core/hub.c:5359 [inline]
>   hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
>   process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
>   worker_thread+0x96/0xe20 kernel/workqueue.c:2415
>   kthread+0x318/0x420 kernel/kthread.c:255
>   ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
>
> Freed by task 83:
>   save_stack+0x1b/0x80 mm/kasan/common.c:69
>   set_track mm/kasan/common.c:77 [inline]
>   __kasan_slab_free+0x130/0x180 mm/kasan/common.c:449
>   slab_free_hook mm/slub.c:1423 [inline]
>   slab_free_freelist_hook mm/slub.c:1474 [inline]
>   slab_free mm/slub.c:3016 [inline]
>   kfree+0xe4/0x2f0 mm/slub.c:3957
>   wdm_create+0x542/0x1720 drivers/usb/class/cdc-wdm.c:884
>   wdm_probe+0x220/0x2d0 drivers/usb/class/cdc-wdm.c:922
>   usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
>   really_probe+0x281/0x6d0 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2165
>   usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
>   generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
>   usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
>   really_probe+0x281/0x6d0 drivers/base/dd.c:548
>   driver_probe_device+0x101/0x1b0 drivers/base/dd.c:721
>   __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
>   bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:454
>   __device_attach+0x217/0x360 drivers/base/dd.c:894
>   bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
>   device_add+0xae6/0x16f0 drivers/base/core.c:2165
>   usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
>   hub_port_connect drivers/usb/core/hub.c:5098 [inline]
>   hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
>   port_event drivers/usb/core/hub.c:5359 [inline]
>   hub_event+0x1b5c/0x3640 drivers/usb/core/hub.c:5441
>   process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
>   worker_thread+0x96/0xe20 kernel/workqueue.c:2415
>   kthread+0x318/0x420 kernel/kthread.c:255
>   ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
>
> The buggy address belongs to the object at ffff8881cbdca880
>   which belongs to the cache kmalloc-1k of size 1024
> The buggy address is located 104 bytes inside of
>   1024-byte region [ffff8881cbdca880, ffff8881cbdcac80)
> The buggy address belongs to the page:
> page:ffffea00072f7200 refcount:1 mapcount:0 mapping:ffff8881da002280
> index:0x0 compound_mapcount: 0
> flags: 0x200000000010200(slab|head)
> raw: 0200000000010200 ffffea000719ca00 0000000400000004 ffff8881da002280
> raw: 0000000000000000 00000000000e000e 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
>
> Memory state around the buggy address:
>   ffff8881cbdca780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>   ffff8881cbdca800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > ffff8881cbdca880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                                                            ^
>   ffff8881cbdca900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>   ffff8881cbdca980: 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@...glegroups.com.
>
> syzbot will keep track of this bug report. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

Most probably the same issue as:

https://syzkaller.appspot.com/bug?id=07a5f1529b95adcb80cbf8729f9cb499b980991d

#syz dup: KASAN: use-after-free Read in wdm_out_callback

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