Message-ID: <000000000000361fc90592b00fa4@google.com>
Date:   Mon, 16 Sep 2019 11:49:10 -0700
From:   syzbot <syzbot+2a4f0b034e05c34252d0@...kaller.appspotmail.com>
To:     bhelgaas@...gle.com, enric.balletbo@...labora.com,
        glider@...gle.com, gregkh@...uxfoundation.org, kirr@...edi.com,
        linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
        lkundrak@...sk, logang@...tatee.com,
        syzkaller-bugs@...glegroups.com
Subject: KMSAN: uninit-value in ld_usb_read

Hello,

syzbot found the following crash on:

HEAD commit:    014077b5 DO-NOT-SUBMIT: usb-fuzzer: main usb gadget fuzzer..
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=1510d63a600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f03c659d0830ab8d
dashboard link: https://syzkaller.appspot.com/bug?extid=2a4f0b034e05c34252d0
compiler:       clang version 9.0.0 (/home/glider/llvm/clang  
80fee25776c2fb61e74c1ecb1a523375c2500b69)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13887b71600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14761d99600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+2a4f0b034e05c34252d0@...kaller.appspotmail.com

ldusb 4-1:0.28: Read buffer overflow, -414328874449497579 bytes dropped
==================================================================
BUG: KMSAN: uninit-value in _copy_to_user+0x1aa/0x1f0 lib/usercopy.c:29
CPU: 0 PID: 12202 Comm: syz-executor155 Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
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_report.c:109
  __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294
  _copy_to_user+0x1aa/0x1f0 lib/usercopy.c:29
  copy_to_user include/linux/uaccess.h:174 [inline]
  ld_usb_read+0x58d/0xc40 drivers/usb/misc/ldusb.c:495
  __vfs_read+0x1a9/0xc90 fs/read_write.c:425
  vfs_read+0x359/0x6f0 fs/read_write.c:461
  ksys_read+0x265/0x430 fs/read_write.c:587
  __do_sys_read fs/read_write.c:597 [inline]
  __se_sys_read+0x92/0xb0 fs/read_write.c:595
  __x64_sys_read+0x4a/0x70 fs/read_write.c:595
  do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:297
  entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x441839
Code: e8 8c e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 cb 08 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd47c58b68 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441839
RDX: 0000001788000335 RSI: 0000000020000140 RDI: 0000000000000004
RBP: 0000000000017997 R08: 000000000000000f R09: 00000009004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402590
R13: 0000000000402620 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
  kmsan_save_stack_with_flags+0x37/0x70 mm/kmsan/kmsan.c:189
  kmsan_internal_alloc_meta_for_pages+0x123/0x510 mm/kmsan/kmsan_hooks.c:114
  kmsan_alloc_page+0x7a/0xf0 mm/kmsan/kmsan_hooks.c:244
  __alloc_pages_nodemask+0x142d/0x5fa0 mm/page_alloc.c:4757
  alloc_pages_current+0x68d/0x9a0 mm/mempolicy.c:2153
  alloc_pages include/linux/gfp.h:511 [inline]
  kmalloc_order mm/slab_common.c:1257 [inline]
  kmalloc_order_trace+0x87/0x320 mm/slab_common.c:1269
  kmalloc_large include/linux/slab.h:485 [inline]
  __kmalloc+0x2e6/0x430 mm/slub.c:3823
  kmalloc_array+0x86/0x110 include/linux/slab.h:676
  ld_usb_probe+0x650/0x1650 drivers/usb/misc/ldusb.c:700
  usb_probe_interface+0xd19/0x1310 drivers/usb/core/driver.c:361
  really_probe+0x1373/0x1dc0 drivers/base/dd.c:552
  driver_probe_device+0x1ba/0x510 drivers/base/dd.c:709
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:816
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
  __device_attach+0x489/0x750 drivers/base/dd.c:882
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:929
  bus_probe_device+0x131/0x390 drivers/base/bus.c:514
  device_add+0x25b5/0x2df0 drivers/base/core.c:2165
  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+0x1373/0x1dc0 drivers/base/dd.c:552
  driver_probe_device+0x1ba/0x510 drivers/base/dd.c:709
  __device_attach_driver+0x5b8/0x790 drivers/base/dd.c:816
  bus_for_each_drv+0x28e/0x3b0 drivers/base/bus.c:454
  __device_attach+0x489/0x750 drivers/base/dd.c:882
  device_initial_probe+0x4a/0x60 drivers/base/dd.c:929
  bus_probe_device+0x131/0x390 drivers/base/bus.c:514
  device_add+0x25b5/0x2df0 drivers/base/core.c:2165
  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
==================================================================


---
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