On Tue, Jun 02, 2020 at 04:36:22PM -0400, Kyungtae Kim wrote:
> We report a bug (in linux-5.6.11) found by FuzzUSB (a modified version
> of syzkaller)
>
> The buf of an usbtest_dev instance (dev->buf) allocated in
> usbtest_probe() leaked.
>
> The usbtest_dev instance holding the buf is attached to a
> corresponding device instance
> through usb_set_intfdata().
> But later, the usbtest_dev instance seems to be freed without
> deallocating its buf field ahead.
>
> kernel config: https://kt0755.github.io/etc/config_v5.6.11
>
> ==
> BUG: memory leak
> unreferenced object 0x888055046e00 (size 256):
> comm "kworker/2:9", pid 2570, jiffies 4294942129 (age 1095.500s)
> hex dump (first 32 bytes):
> 00 70 04 55 80 88 ff ff 18 bb 5a 81 ff ff ff ff .p.U..Z.
> f5 96 78 81 ff ff ff ff 37 de 8e 81 ff ff ff ff ..x.7...
> backtrace:
> [] kmemleak_alloc_recursive
> include/linux/kmemleak.h:43 [inline]
> [] slab_post_alloc_hook mm/slab.h:586 [inline]
> [] slab_alloc_node mm/slub.c:2786 [inline]
> [] slab_alloc mm/slub.c:2794 [inline]
> [] kmem_cache_alloc_trace+0x15e/0x2d0 mm/slub.c:2811
> [<5c3c3381>] kmalloc include/linux/slab.h:555 [inline]
> [<5c3c3381>] usbtest_probe+0x286/0x19d0
> drivers/usb/misc/usbtest.c:2790
> [<1cec6910>] usb_probe_interface+0x2bd/0x870
> drivers/usb/core/driver.c:361
> [<7806c118>] really_probe+0x48d/0x8f0 drivers/base/dd.c:551
> [] driver_probe_device+0xfc/0x2a0 drivers/base/dd.c:724
> [<3ef66004>] __device_attach_driver+0x1b6/0x240
> drivers/base/dd.c:831
> [] bus_for_each_drv+0x14e/0x1e0 drivers/base/bus.c:431
> [] __device_attach+0x1f9/0x350 drivers/base/dd.c:897
> [<838b324a>] device_initial_probe+0x1a/0x20 drivers/base/dd.c:944
> [<30d501c1>] bus_probe_device+0x1e1/0x280 drivers/base/bus.c:491
> [<5bd7adef>] device_add+0x131d/0x1c40 drivers/base/core.c:2504
> [] usb_set_configuration+0xe84/0x1ab0
> drivers/usb/core/message.c:2030
> [] generic_probe+0x6a/0xe0
> drivers/usb/core/generic.c:210
> [<98ade0f1>] usb_probe_device+0x90/0xd0
> drivers/usb/core/driver.c:266
> [<7806c118>] really_probe+0x48d/0x8f0 drivers/base/dd.c:551
> [] driver_probe_device+0xfc/0x2a0 drivers/base/dd.c:724
> ==
Can you send a patch to fix this so that you get full credit for
finding, and fixing the issue?
thanks,
greg k-h
