Hi Oliver, Thanks for the fix. You need to set an invalid return code, too. Regards, Guido -----Original Message----- From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Sent: Wednesday, August 14, 2019 3:52 PM To: syzbot <syzbot+55b0304b360654a7537b@xxxxxxxxxxxxxxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>; Kiener Guido 1DS1 <Guido.Kiener@xxxxxxxxxxxxxxxxx>; USB list <linux-usb@xxxxxxxxxxxxxxx>; Oliver Neukum <oneukum@xxxxxxxx>; steve_bayless@xxxxxxxxxxxx; syzkaller-bugs <syzkaller-bugs@xxxxxxxxxxxxxxxx> Subject: *EXT* Re: divide error in usbtmc_generic_read On Wed, Aug 14, 2019 at 3:38 PM syzbot <syzbot+55b0304b360654a7537b@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot has tested the proposed patch but the reproducer still > triggered > crash: > KASAN: use-after-free Read in usbtmc_disconnect Looks like a different bug in the same driver that gets triggered by the same reproducer =) You fix looks good to me. > > usb 5-1: USB disconnect, device number 2 > ================================================================== > BUG: KASAN: use-after-free in __mutex_lock_common > kernel/locking/mutex.c:912 [inline] > BUG: KASAN: use-after-free in __mutex_lock+0xf23/0x1360 > kernel/locking/mutex.c:1077 > Read of size 8 at addr ffff8881d63299c8 by task kworker/1:0/17 > > CPU: 1 PID: 17 Comm: kworker/1:0 Not tainted 5.3.0-rc4+ #1 Hardware > name: Google Google Compute Engine/Google Compute Engine, BIOS Google > 01/01/2011 > Workqueue: usb_hub_wq hub_event > Call Trace: > __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 > __mutex_lock_common kernel/locking/mutex.c:912 [inline] > __mutex_lock+0xf23/0x1360 kernel/locking/mutex.c:1077 > usbtmc_disconnect+0x58/0x180 drivers/usb/class/usbtmc.c:2443 > usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423 > __device_release_driver drivers/base/dd.c:1134 [inline] > device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165 > bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556 > device_del+0x420/0xb10 drivers/base/core.c:2339 > usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237 > usb_disconnect+0x284/0x8d0 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+0x1454/0x3640 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 > > Allocated by task 1737: > 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] > usbtmc_probe+0xad/0x1360 drivers/usb/class/usbtmc.c:2328 > 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 1737: > 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 > kref_put include/linux/kref.h:65 [inline] > usbtmc_probe+0x55c/0x1360 drivers/usb/class/usbtmc.c:2433 > 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 ffff8881d6329900 > which belongs to the cache kmalloc-512 of size 512 The buggy address > is located 200 bytes inside of > 512-byte region [ffff8881d6329900, ffff8881d6329b00) The buggy > address belongs to the page: > page:ffffea000758ca00 refcount:1 mapcount:0 mapping:ffff8881da002500 > index:0x0 compound_mapcount: 0 > flags: 0x200000000010200(slab|head) > raw: 0200000000010200 ffffea0007585680 0000000700000007 > ffff8881da002500 > raw: 0000000000000000 00000000000c000c 00000001ffffffff > 0000000000000000 page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8881d6329880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8881d6329900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > > ffff8881d6329980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8881d6329a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8881d6329a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > Tested on: > > commit: d0847550 usb-fuzzer: main usb gadget fuzzer driver > git tree: https://github.com/google/kasan.git > console output: > https://syzkaller.appspot.com/x/log.txt?x=10ac29ee600000 > kernel config: https://syzkaller.appspot.com/x/.config?x=dbc9c80cc095da19 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > patch: https://syzkaller.appspot.com/x/patch.diff?x=11f3b2e2600000 >
