KMSAN: uninit-value in dvb_usb_adapter_dvb_init

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 6f88939b kmsan: don't unpoison memory in do_read_cache_pag..
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=101311a2e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9e324dfe9c7b0360
dashboard link: https://syzkaller.appspot.com/bug?extid=ec869945d3dde5f33b43
compiler: clang version 9.0.0 (/home/glider/llvm/clang
80fee25776c2fb61e74c1ecb1a523375c2500b69)

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+ec8699...@syzkaller.appspotmail.com

vp7045: USB control message 'out' went wrong.
vp7045: USB control message 'out' went wrong.
vp7045: USB control message 'out' went wrong.
vp7045: USB control message 'out' went wrong.
=====================================================
BUG: KMSAN: uninit-value in mac_address_string+0xcd5/0x1000
lib/vsprintf.c:604
CPU: 0 PID: 13542 Comm: kworker/0:7 Not tainted 5.4.0-rc5+ #0
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+0x128/0x220 mm/kmsan/kmsan_report.c:108
__msan_warning+0x73/0xe0 mm/kmsan/kmsan_instr.c:245
mac_address_string+0xcd5/0x1000 lib/vsprintf.c:604
pointer+0x56d/0x1d10 lib/vsprintf.c:2148
vsnprintf+0x1c0c/0x3210 lib/vsprintf.c:2514
vscnprintf+0xc2/0x180 lib/vsprintf.c:2613
vprintk_store+0xef/0x11e0 kernel/printk/printk.c:1922
vprintk_emit+0x2c6/0x860 kernel/printk/printk.c:1984
vprintk_default+0x90/0xa0 kernel/printk/printk.c:2029
vprintk_func+0x635/0x810 kernel/printk/printk_safe.c:386
printk+0x180/0x1c3 kernel/printk/printk.c:2062
dvb_usb_adapter_dvb_init+0x90e/0x13f0
drivers/media/usb/dvb-usb/dvb-usb-dvb.c:166
dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:83 [inline]
dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:173 [inline]
dvb_usb_device_init+0x22fe/0x2e10
drivers/media/usb/dvb-usb/dvb-usb-init.c:287
vp7045_usb_probe+0x73/0x80 drivers/media/usb/dvb-usb/vp7045.c:164
usb_probe_interface+0xd19/0x1310 drivers/usb/core/driver.c:361
really_probe+0xd91/0x1f90 drivers/base/dd.c:552
driver_probe_device+0x1ba/0x510 drivers/base/dd.c:721
__device_attach_driver+0x5b8/0x790 drivers/base/dd.c:828
bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:430
__device_attach+0x489/0x750 drivers/base/dd.c:894
device_initial_probe+0x4a/0x60 drivers/base/dd.c:941
bus_probe_device+0x131/0x390 drivers/base/bus.c:490
device_add+0x25b5/0x2df0 drivers/base/core.c:2202
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+0xd91/0x1f90 drivers/base/dd.c:552
driver_probe_device+0x1ba/0x510 drivers/base/dd.c:721
__device_attach_driver+0x5b8/0x790 drivers/base/dd.c:828
bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:430
__device_attach+0x489/0x750 drivers/base/dd.c:894
device_initial_probe+0x4a/0x60 drivers/base/dd.c:941
bus_probe_device+0x131/0x390 drivers/base/bus.c:490
device_add+0x25b5/0x2df0 drivers/base/core.c:2202
usb_new_device+0x23e5/0x2fb0 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+0x581d/0x72f0 drivers/usb/core/hub.c:5441
process_one_work+0x1572/0x1ef0 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

Uninit was stored to memory at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:151 [inline]
kmsan_internal_chain_origin+0xbd/0x180 mm/kmsan/kmsan.c:319
__msan_chain_origin+0x6b/0xd0 mm/kmsan/kmsan_instr.c:179
vp7045_read_eeprom drivers/media/usb/dvb-usb/vp7045.c:123 [inline]
vp7045_read_mac_addr+0x62e/0xbe0 drivers/media/usb/dvb-usb/vp7045.c:132
dvb_usb_adapter_dvb_init+0x890/0x13f0
drivers/media/usb/dvb-usb/dvb-usb-dvb.c:165
dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:83 [inline]
dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:173 [inline]
dvb_usb_device_init+0x22fe/0x2e10
drivers/media/usb/dvb-usb/dvb-usb-init.c:287
vp7045_usb_probe+0x73/0x80 drivers/media/usb/dvb-usb/vp7045.c:164
usb_probe_interface+0xd19/0x1310 drivers/usb/core/driver.c:361
really_probe+0xd91/0x1f90 drivers/base/dd.c:552
driver_probe_device+0x1ba/0x510 drivers/base/dd.c:721
__device_attach_driver+0x5b8/0x790 drivers/base/dd.c:828
bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:430
__device_attach+0x489/0x750 drivers/base/dd.c:894
device_initial_probe+0x4a/0x60 drivers/base/dd.c:941
bus_probe_device+0x131/0x390 drivers/base/bus.c:490
device_add+0x25b5/0x2df0 drivers/base/core.c:2202
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+0xd91/0x1f90 drivers/base/dd.c:552
driver_probe_device+0x1ba/0x510 drivers/base/dd.c:721
__device_attach_driver+0x5b8/0x790 drivers/base/dd.c:828
bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:430
__device_attach+0x489/0x750 drivers/base/dd.c:894
device_initial_probe+0x4a/0x60 drivers/base/dd.c:941
bus_probe_device+0x131/0x390 drivers/base/bus.c:490
device_add+0x25b5/0x2df0 drivers/base/core.c:2202
usb_new_device+0x23e5/0x2fb0 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+0x581d/0x72f0 drivers/usb/core/hub.c:5441
process_one_work+0x1572/0x1ef0 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: ----br.i@vp7045_read_mac_addr
Variable was created at:
vp7045_read_eeprom drivers/media/usb/dvb-usb/vp7045.c:119 [inline]
vp7045_read_mac_addr+0x7b/0xbe0 drivers/media/usb/dvb-usb/vp7045.c:132
vp7045_read_eeprom drivers/media/usb/dvb-usb/vp7045.c:119 [inline]
vp7045_read_mac_addr+0x7b/0xbe0 drivers/media/usb/dvb-usb/vp7045.c:132
=====================================================


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[syzbot]

> #syz test: https://github.com/google/kmsan.git master

This crash does not have a reproducer. I cannot test it.