KMSAN: uninit-value in rt2500usb_bbp_read

From: syzbot
Date: Thu Jun 06 2019 - 05:46:11 EST

Hello,

syzbot found the following crash on:

HEAD commit: f75e4cfe kmsan: use kmsan_handle_urb() in urb.c
git tree: kmsan
console output: https://syzkaller.appspot.com/x/log.txt?x=12f8b01ea00000
kernel config: https://syzkaller.appspot.com/x/.config?x=602468164ccdc30a
dashboard link: https://syzkaller.appspot.com/bug?extid=a106a5b084a6890d2607
compiler: clang version 9.0.0 (/home/glider/llvm/clang 06d00afa61eef8f7f501ebdb4e8612ea43ec2d78)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14f746f2a00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=153072d2a00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+a106a5b084a6890d2607@xxxxxxxxxxxxxxxxxxxxxxxxx

usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 1-1: config 0 descriptor??
usb 1-1: reset high-speed USB device number 2 using dummy_hcd
usb 1-1: device descriptor read/64, error -71
ieee80211 phy3: rt2x00usb_vendor_request: Error - Vendor Request 0x09 failed for offset 0x0000 with error -71
ieee80211 phy3: rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x04d0 with error -71
==================================================================
BUG: KMSAN: uninit-value in rt2500usb_regbusy_read drivers/net/wireless/ralink/rt2x00/rt2500usb.c:116 [inline]
BUG: KMSAN: uninit-value in rt2500usb_bbp_read+0x174/0x640 drivers/net/wireless/ralink/rt2x00/rt2500usb.c:172
CPU: 1 PID: 4943 Comm: kworker/1:2 Not tainted 5.1.0+ #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+0x191/0x1f0 lib/dump_stack.c:113
kmsan_report+0x130/0x2a0 mm/kmsan/kmsan.c:622
__msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:310
rt2500usb_regbusy_read drivers/net/wireless/ralink/rt2x00/rt2500usb.c:116 [inline]
rt2500usb_bbp_read+0x174/0x640 drivers/net/wireless/ralink/rt2x00/rt2500usb.c:172
rt2500usb_validate_eeprom drivers/net/wireless/ralink/rt2x00/rt2500usb.c:1387 [inline]
rt2500usb_probe_hw+0x3b1/0x2230 drivers/net/wireless/ralink/rt2x00/rt2500usb.c:1764
rt2x00lib_probe_dev+0xb81/0x3090 drivers/net/wireless/ralink/rt2x00/rt2x00dev.c:1427
rt2x00usb_probe+0x7c7/0xf70 drivers/net/wireless/ralink/rt2x00/rt2x00usb.c:837
rt2500usb_probe+0x50/0x60 drivers/net/wireless/ralink/rt2x00/rt2500usb.c:1977
usb_probe_interface+0xd66/0x1320 drivers/usb/core/driver.c:361
really_probe+0xdae/0x1d80 drivers/base/dd.c:513
driver_probe_device+0x1b3/0x4f0 drivers/base/dd.c:671
__device_attach_driver+0x5b8/0x790 drivers/base/dd.c:778
bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
__device_attach+0x454/0x730 drivers/base/dd.c:844
device_initial_probe+0x4a/0x60 drivers/base/dd.c:891
bus_probe_device+0x137/0x390 drivers/base/bus.c:514
device_add+0x288d/0x30e0 drivers/base/core.c:2106
usb_set_configuration+0x30dc/0x3750 drivers/usb/core/message.c:2027
generic_probe+0xe7/0x280 drivers/usb/core/generic.c:210
usb_probe_device+0x14c/0x200 drivers/usb/core/driver.c:266
really_probe+0xdae/0x1d80 drivers/base/dd.c:513
driver_probe_device+0x1b3/0x4f0 drivers/base/dd.c:671
__device_attach_driver+0x5b8/0x790 drivers/base/dd.c:778
bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
__device_attach+0x454/0x730 drivers/base/dd.c:844
device_initial_probe+0x4a/0x60 drivers/base/dd.c:891
bus_probe_device+0x137/0x390 drivers/base/bus.c:514
device_add+0x288d/0x30e0 drivers/base/core.c:2106
usb_new_device+0x23e5/0x2ff0 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+0x48d1/0x7290 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:254
ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:355

Local variable description: ----reg.i.i@rt2500usb_bbp_read
Variable was created at:
rt2500usb_register_read_lock drivers/net/wireless/ralink/rt2x00/rt2500usb.c:72 [inline]
rt2500usb_regbusy_read drivers/net/wireless/ralink/rt2x00/rt2500usb.c:115 [inline]
rt2500usb_bbp_read+0xa4/0x640 drivers/net/wireless/ralink/rt2x00/rt2500usb.c:172
rt2500usb_validate_eeprom drivers/net/wireless/ralink/rt2x00/rt2500usb.c:1387 [inline]
rt2500usb_probe_hw+0x3b1/0x2230 drivers/net/wireless/ralink/rt2x00/rt2500usb.c:1764
==================================================================


---
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