2020-12-08 16:07:53

by Alan Stern

[permalink] [raw]
Subject: Re: general protection fault in tower_disconnect

On Tue, Dec 08, 2020 at 03:53:16AM -0800, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 08a02f95 USB: add RESET_RESUME quirk for Snapscan 1212
> git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
> console output: https://syzkaller.appspot.com/x/log.txt?x=1435927b500000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d24ee9ecd7ce968e
> dashboard link: https://syzkaller.appspot.com/bug?extid=9be25235b7a69b24d117
> compiler: gcc (GCC) 10.1.0-syz 20200507
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15145f07500000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b99413500000
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>
> usb 1-1: USB disconnect, device number 2
> general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] SMP KASAN
> KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
> CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.10.0-rc7-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Workqueue: usb_hub_wq hub_event
> RIP: 0010:tower_disconnect+0x53/0x360 drivers/usb/misc/legousbtower.c:848
> Code: 03 80 3c 02 00 0f 85 15 03 00 00 48 8b ab a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bd 98 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7b 02 00 00 48 c7 c6 40 07 bb 87 48
> RSP: 0018:ffffc9000007f7c0 EFLAGS: 00010202
> RAX: dffffc0000000000 RBX: ffff888117ec0000 RCX: ffffffff8381f807
> RDX: 0000000000000013 RSI: ffffffff83bab792 RDI: 0000000000000098
> RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff898cc4ef
> R10: 0000000000000002 R11: 0000000000000000 R12: ffff888117ec0090
> R13: ffff888117ec0078 R14: ffff888117ec0030 R15: ffff888117ec0098
> FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f557af47550 CR3: 00000001090f3000 CR4: 00000000001506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
> usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458
> __device_release_driver+0x3bd/0x6f0 drivers/base/dd.c:1154
> device_release_driver_internal drivers/base/dd.c:1185 [inline]
> device_release_driver+0x26/0x40 drivers/base/dd.c:1208
> bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:533
> device_del+0x502/0xec0 drivers/base/core.c:3115
> usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1413
> usb_disconnect.cold+0x27d/0x780 drivers/usb/core/hub.c:2218
> hub_port_connect drivers/usb/core/hub.c:5074 [inline]
> hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
> port_event drivers/usb/core/hub.c:5509 [inline]
> hub_event+0x1c8a/0x42d0 drivers/usb/core/hub.c:5591
> process_one_work+0x933/0x1520 kernel/workqueue.c:2272
> worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
> kthread+0x38c/0x460 kernel/kthread.c:292
> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
> Modules linked in:
> ---[ end trace 5aeb1d199be5d5f2 ]---
> RIP: 0010:tower_disconnect+0x53/0x360 drivers/usb/misc/legousbtower.c:848
> Code: 03 80 3c 02 00 0f 85 15 03 00 00 48 8b ab a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bd 98 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7b 02 00 00 48 c7 c6 40 07 bb 87 48
> RSP: 0018:ffffc9000007f7c0 EFLAGS: 00010202
> RAX: dffffc0000000000 RBX: ffff888117ec0000 RCX: ffffffff8381f807
> RDX: 0000000000000013 RSI: ffffffff83bab792 RDI: 0000000000000098
> RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff898cc4ef
> R10: 0000000000000002 R11: 0000000000000000 R12: ffff888117ec0090
> R13: ffff888117ec0078 R14: ffff888117ec0030 R15: ffff888117ec0098
> FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f557af47550 CR3: 00000001090f3000 CR4: 00000000001506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

This is a simple thinko.

Alan Stern

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 08a02f95

Index: usb-devel/drivers/usb/misc/legousbtower.c
===================================================================
--- usb-devel.orig/drivers/usb/misc/legousbtower.c
+++ usb-devel/drivers/usb/misc/legousbtower.c
@@ -797,7 +797,7 @@ static int tower_probe(struct usb_interf
&get_version_reply,
sizeof(get_version_reply),
1000, GFP_KERNEL);
- if (!result) {
+ if (result) {
dev_err(idev, "get version request failed: %d\n", result);
retval = result;
goto error;


2020-12-08 16:09:19

by syzbot

[permalink] [raw]
Subject: Re: Re: general protection fault in tower_disconnect

> On Tue, Dec 08, 2020 at 03:53:16AM -0800, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: 08a02f95 USB: add RESET_RESUME quirk for Snapscan 1212
>> git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
>> console output: https://syzkaller.appspot.com/x/log.txt?x=1435927b500000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=d24ee9ecd7ce968e
>> dashboard link: https://syzkaller.appspot.com/bug?extid=9be25235b7a69b24d117
>> compiler: gcc (GCC) 10.1.0-syz 20200507
>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15145f07500000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b99413500000
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: [email protected]
>>
>> usb 1-1: USB disconnect, device number 2
>> general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] SMP KASAN
>> KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
>> CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.10.0-rc7-syzkaller #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
>> Workqueue: usb_hub_wq hub_event
>> RIP: 0010:tower_disconnect+0x53/0x360 drivers/usb/misc/legousbtower.c:848
>> Code: 03 80 3c 02 00 0f 85 15 03 00 00 48 8b ab a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bd 98 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7b 02 00 00 48 c7 c6 40 07 bb 87 48
>> RSP: 0018:ffffc9000007f7c0 EFLAGS: 00010202
>> RAX: dffffc0000000000 RBX: ffff888117ec0000 RCX: ffffffff8381f807
>> RDX: 0000000000000013 RSI: ffffffff83bab792 RDI: 0000000000000098
>> RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff898cc4ef
>> R10: 0000000000000002 R11: 0000000000000000 R12: ffff888117ec0090
>> R13: ffff888117ec0078 R14: ffff888117ec0030 R15: ffff888117ec0098
>> FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007f557af47550 CR3: 00000001090f3000 CR4: 00000000001506f0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>> usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458
>> __device_release_driver+0x3bd/0x6f0 drivers/base/dd.c:1154
>> device_release_driver_internal drivers/base/dd.c:1185 [inline]
>> device_release_driver+0x26/0x40 drivers/base/dd.c:1208
>> bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:533
>> device_del+0x502/0xec0 drivers/base/core.c:3115
>> usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1413
>> usb_disconnect.cold+0x27d/0x780 drivers/usb/core/hub.c:2218
>> hub_port_connect drivers/usb/core/hub.c:5074 [inline]
>> hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
>> port_event drivers/usb/core/hub.c:5509 [inline]
>> hub_event+0x1c8a/0x42d0 drivers/usb/core/hub.c:5591
>> process_one_work+0x933/0x1520 kernel/workqueue.c:2272
>> worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
>> kthread+0x38c/0x460 kernel/kthread.c:292
>> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
>> Modules linked in:
>> ---[ end trace 5aeb1d199be5d5f2 ]---
>> RIP: 0010:tower_disconnect+0x53/0x360 drivers/usb/misc/legousbtower.c:848
>> Code: 03 80 3c 02 00 0f 85 15 03 00 00 48 8b ab a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bd 98 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7b 02 00 00 48 c7 c6 40 07 bb 87 48
>> RSP: 0018:ffffc9000007f7c0 EFLAGS: 00010202
>> RAX: dffffc0000000000 RBX: ffff888117ec0000 RCX: ffffffff8381f807
>> RDX: 0000000000000013 RSI: ffffffff83bab792 RDI: 0000000000000098
>> RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff898cc4ef
>> R10: 0000000000000002 R11: 0000000000000000 R12: ffff888117ec0090
>> R13: ffff888117ec0078 R14: ffff888117ec0030 R15: ffff888117ec0098
>> FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007f557af47550 CR3: 00000001090f3000 CR4: 00000000001506f0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
> This is a simple thinko.
>
> Alan Stern
>
> #syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 08a02f95

want 2 args (repo, branch), got 3

>
> Index: usb-devel/drivers/usb/misc/legousbtower.c
> ===================================================================
> --- usb-devel.orig/drivers/usb/misc/legousbtower.c
> +++ usb-devel/drivers/usb/misc/legousbtower.c
> @@ -797,7 +797,7 @@ static int tower_probe(struct usb_interf
> &get_version_reply,
> sizeof(get_version_reply),
> 1000, GFP_KERNEL);
> - if (!result) {
> + if (result) {
> dev_err(idev, "get version request failed: %d\n", result);
> retval = result;
> goto error;
>
> --
> You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/20201208160425.GA1298255%40rowland.harvard.edu.

2020-12-08 16:09:24

by syzbot

[permalink] [raw]
Subject: Re: Re: general protection fault in tower_disconnect

> On Tue, Dec 08, 2020 at 03:53:16AM -0800, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: 08a02f95 USB: add RESET_RESUME quirk for Snapscan 1212
>> git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
>> console output: https://syzkaller.appspot.com/x/log.txt?x=1435927b500000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=d24ee9ecd7ce968e
>> dashboard link: https://syzkaller.appspot.com/bug?extid=9be25235b7a69b24d117
>> compiler: gcc (GCC) 10.1.0-syz 20200507
>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15145f07500000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b99413500000
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: [email protected]
>>
>> usb 1-1: USB disconnect, device number 2
>> general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] SMP KASAN
>> KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
>> CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.10.0-rc7-syzkaller #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
>> Workqueue: usb_hub_wq hub_event
>> RIP: 0010:tower_disconnect+0x53/0x360 drivers/usb/misc/legousbtower.c:848
>> Code: 03 80 3c 02 00 0f 85 15 03 00 00 48 8b ab a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bd 98 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7b 02 00 00 48 c7 c6 40 07 bb 87 48
>> RSP: 0018:ffffc9000007f7c0 EFLAGS: 00010202
>> RAX: dffffc0000000000 RBX: ffff888117ec0000 RCX: ffffffff8381f807
>> RDX: 0000000000000013 RSI: ffffffff83bab792 RDI: 0000000000000098
>> RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff898cc4ef
>> R10: 0000000000000002 R11: 0000000000000000 R12: ffff888117ec0090
>> R13: ffff888117ec0078 R14: ffff888117ec0030 R15: ffff888117ec0098
>> FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007f557af47550 CR3: 00000001090f3000 CR4: 00000000001506f0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> Call Trace:
>> usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458
>> __device_release_driver+0x3bd/0x6f0 drivers/base/dd.c:1154
>> device_release_driver_internal drivers/base/dd.c:1185 [inline]
>> device_release_driver+0x26/0x40 drivers/base/dd.c:1208
>> bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:533
>> device_del+0x502/0xec0 drivers/base/core.c:3115
>> usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1413
>> usb_disconnect.cold+0x27d/0x780 drivers/usb/core/hub.c:2218
>> hub_port_connect drivers/usb/core/hub.c:5074 [inline]
>> hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
>> port_event drivers/usb/core/hub.c:5509 [inline]
>> hub_event+0x1c8a/0x42d0 drivers/usb/core/hub.c:5591
>> process_one_work+0x933/0x1520 kernel/workqueue.c:2272
>> worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
>> kthread+0x38c/0x460 kernel/kthread.c:292
>> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
>> Modules linked in:
>> ---[ end trace 5aeb1d199be5d5f2 ]---
>> RIP: 0010:tower_disconnect+0x53/0x360 drivers/usb/misc/legousbtower.c:848
>> Code: 03 80 3c 02 00 0f 85 15 03 00 00 48 8b ab a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bd 98 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7b 02 00 00 48 c7 c6 40 07 bb 87 48
>> RSP: 0018:ffffc9000007f7c0 EFLAGS: 00010202
>> RAX: dffffc0000000000 RBX: ffff888117ec0000 RCX: ffffffff8381f807
>> RDX: 0000000000000013 RSI: ffffffff83bab792 RDI: 0000000000000098
>> RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff898cc4ef
>> R10: 0000000000000002 R11: 0000000000000000 R12: ffff888117ec0090
>> R13: ffff888117ec0078 R14: ffff888117ec0030 R15: ffff888117ec0098
>> FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000
>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 00007f557af47550 CR3: 00000001090f3000 CR4: 00000000001506f0
>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
> This is a simple thinko.
>
> Alan Stern
>
> #syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 08a02f95

want 2 args (repo, branch), got 3

>
> Index: usb-devel/drivers/usb/misc/legousbtower.c
> ===================================================================
> --- usb-devel.orig/drivers/usb/misc/legousbtower.c
> +++ usb-devel/drivers/usb/misc/legousbtower.c
> @@ -797,7 +797,7 @@ static int tower_probe(struct usb_interf
> &get_version_reply,
> sizeof(get_version_reply),
> 1000, GFP_KERNEL);
> - if (!result) {
> + if (result) {
> dev_err(idev, "get version request failed: %d\n", result);
> retval = result;
> goto error;
>

2020-12-08 20:26:21

by Alan Stern

[permalink] [raw]
Subject: Re: general protection fault in tower_disconnect

On Tue, Dec 08, 2020 at 11:04:25AM -0500, Alan Stern wrote:
> On Tue, Dec 08, 2020 at 03:53:16AM -0800, syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit: 08a02f95 USB: add RESET_RESUME quirk for Snapscan 1212
> > git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
> > console output: https://syzkaller.appspot.com/x/log.txt?x=1435927b500000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=d24ee9ecd7ce968e
> > dashboard link: https://syzkaller.appspot.com/bug?extid=9be25235b7a69b24d117
> > compiler: gcc (GCC) 10.1.0-syz 20200507
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15145f07500000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16b99413500000
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: [email protected]
> >
> > usb 1-1: USB disconnect, device number 2
> > general protection fault, probably for non-canonical address 0xdffffc0000000013: 0000 [#1] SMP KASAN
> > KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]
> > CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.10.0-rc7-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > Workqueue: usb_hub_wq hub_event
> > RIP: 0010:tower_disconnect+0x53/0x360 drivers/usb/misc/legousbtower.c:848
> > Code: 03 80 3c 02 00 0f 85 15 03 00 00 48 8b ab a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bd 98 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7b 02 00 00 48 c7 c6 40 07 bb 87 48
> > RSP: 0018:ffffc9000007f7c0 EFLAGS: 00010202
> > RAX: dffffc0000000000 RBX: ffff888117ec0000 RCX: ffffffff8381f807
> > RDX: 0000000000000013 RSI: ffffffff83bab792 RDI: 0000000000000098
> > RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff898cc4ef
> > R10: 0000000000000002 R11: 0000000000000000 R12: ffff888117ec0090
> > R13: ffff888117ec0078 R14: ffff888117ec0030 R15: ffff888117ec0098
> > FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000
> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f557af47550 CR3: 00000001090f3000 CR4: 00000000001506f0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > Call Trace:
> > usb_unbind_interface+0x1d8/0x8d0 drivers/usb/core/driver.c:458
> > __device_release_driver+0x3bd/0x6f0 drivers/base/dd.c:1154
> > device_release_driver_internal drivers/base/dd.c:1185 [inline]
> > device_release_driver+0x26/0x40 drivers/base/dd.c:1208
> > bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:533
> > device_del+0x502/0xec0 drivers/base/core.c:3115
> > usb_disable_device+0x35b/0x7b0 drivers/usb/core/message.c:1413
> > usb_disconnect.cold+0x27d/0x780 drivers/usb/core/hub.c:2218
> > hub_port_connect drivers/usb/core/hub.c:5074 [inline]
> > hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
> > port_event drivers/usb/core/hub.c:5509 [inline]
> > hub_event+0x1c8a/0x42d0 drivers/usb/core/hub.c:5591
> > process_one_work+0x933/0x1520 kernel/workqueue.c:2272
> > worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
> > kthread+0x38c/0x460 kernel/kthread.c:292
> > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
> > Modules linked in:
> > ---[ end trace 5aeb1d199be5d5f2 ]---
> > RIP: 0010:tower_disconnect+0x53/0x360 drivers/usb/misc/legousbtower.c:848
> > Code: 03 80 3c 02 00 0f 85 15 03 00 00 48 8b ab a8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d bd 98 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 06 0f 8e 7b 02 00 00 48 c7 c6 40 07 bb 87 48
> > RSP: 0018:ffffc9000007f7c0 EFLAGS: 00010202
> > RAX: dffffc0000000000 RBX: ffff888117ec0000 RCX: ffffffff8381f807
> > RDX: 0000000000000013 RSI: ffffffff83bab792 RDI: 0000000000000098
> > RBP: 0000000000000000 R08: 0000000000000001 R09: ffffffff898cc4ef
> > R10: 0000000000000002 R11: 0000000000000000 R12: ffff888117ec0090
> > R13: ffff888117ec0078 R14: ffff888117ec0030 R15: ffff888117ec0098
> > FS: 0000000000000000(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000
> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f557af47550 CR3: 00000001090f3000 CR4: 00000000001506f0
> > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
> This is a simple thinko.

And there was one in my response. Sigh.

Alan Stern

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git 08a02f95

Index: usb-devel/drivers/usb/misc/legousbtower.c
===================================================================
--- usb-devel.orig/drivers/usb/misc/legousbtower.c
+++ usb-devel/drivers/usb/misc/legousbtower.c
@@ -797,7 +797,7 @@ static int tower_probe(struct usb_interf
&get_version_reply,
sizeof(get_version_reply),
1000, GFP_KERNEL);
- if (!result) {
+ if (result) {
dev_err(idev, "get version request failed: %d\n", result);
retval = result;
goto error;