KMSAN: uninit-value in dib3000mb_attach (2)

KMSAN: uninit-value in dib3000mb_attach (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    3351e2b9 usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=1249ce95a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=40511ad0c5945201
dashboard link: https://syzkaller.appspot.com/bug?extid=c88fc0ebe0d5935c70da
compiler:       clang version 9.0.0 (/home/glider/llvm/clang 80fee25776c2fb61e74c1ecb1a523375c2500b69)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14f81fb9a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13577d85a00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c88fc0ebe0d5935c70da@syzkaller.appspotmail.com

dvb-usb: will use the device's hardware PID filter (table count: 16).
dvbdev: DVB: registering new adapter (Grandtec USB1.1 DVB-T)
usb 1-1: media controller created
dvbdev: dvb_create_media_entity: media entity 'dvb-demux' registered.
dvb-usb: bulk message failed: -22 (6/-30592)
==================================================================
BUG: KMSAN: uninit-value in dib3000mb_attach+0x340/0x450 drivers/media/dvb-frontends/dib3000mb.c:762
CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.2.0-rc4+ #5
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+0x191/0x1f0 lib/dump_stack.c:113
 kmsan_report+0x162/0x2d0 mm/kmsan/kmsan.c:611
 __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:304
 dib3000mb_attach+0x340/0x450 drivers/media/dvb-frontends/dib3000mb.c:762
 dibusb_dib3000mb_frontend_attach+0x1af/0x3b0 drivers/media/usb/dvb-usb/dibusb-mb.c:34
 dvb_usb_adapter_frontend_init+0x105/0xa00 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:291
 dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:84 [inline]
 dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:160 [inline]
 dvb_usb_device_init+0x2297/0x2cc0 drivers/media/usb/dvb-usb/dvb-usb-init.c:274
 dibusb_probe+0x75/0x280 drivers/media/usb/dvb-usb/dibusb-mb.c:113
 usb_probe_interface+0xd19/0x1310 drivers/usb/core/driver.c:361
 really_probe+0x1344/0x1d90 drivers/base/dd.c:513
 driver_probe_device+0x1ba/0x510 drivers/base/dd.c:670
 __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:777
 bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
 __device_attach+0x489/0x750 drivers/base/dd.c:843
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:890
 bus_probe_device+0x131/0x390 drivers/base/bus.c:514
 device_add+0x25b5/0x2df0 drivers/base/core.c:2111
 usb_set_configuration+0x309f/0x3710 drivers/usb/core/message.c:2027
 generic_probe+0xe7/0x280 drivers/usb/core/generic.c:210
 usb_probe_device+0x146/0x200 drivers/usb/core/driver.c:266
 really_probe+0x1344/0x1d90 drivers/base/dd.c:513
 driver_probe_device+0x1ba/0x510 drivers/base/dd.c:670
 __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:777
 bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
 __device_attach+0x489/0x750 drivers/base/dd.c:843
 device_initial_probe+0x4a/0x60 drivers/base/dd.c:890
 bus_probe_device+0x131/0x390 drivers/base/bus.c:514
 device_add+0x25b5/0x2df0 drivers/base/core.c:2111
 usb_new_device+0x23e5/0x2fb0 drivers/usb/core/hub.c:2534
 hub_port_connect drivers/usb/core/hub.c:5089 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5204 [inline]
 port_event drivers/usb/core/hub.c:5350 [inline]
 hub_event+0x5853/0x7320 drivers/usb/core/hub.c:5432
 process_one_work+0x1572/0x1f00 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

Local variable description: ----rb@dib3000_read_reg
Variable was created at:
 dib3000_read_reg+0xdb/0x540 drivers/media/dvb-frontends/dib3000mb.c:58
 dib3000mb_attach+0x17d/0x450 drivers/media/dvb-frontends/dib3000mb.c:762
==================================================================


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