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SubjectKASAN: slab-out-of-bounds Read in mark_lock
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Hello,

syzbot found the following crash on:

HEAD commit: d2f8825a Merge tag 'for_linus' of git://git.kernel.org/pub..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=132ed272100000
kernel config: https://syzkaller.appspot.com/x/.config?x=c33c7f7c5471fd39
dashboard link: https://syzkaller.appspot.com/bug?extid=31610284091be1bf04f4
compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14797b81100000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11f86d6e100000

The bug was bisected to:

commit f2c2e717642c66f7fe7e5dd69b2e8ff5849f4d10
Author: Andrey Konovalov <andreyknvl@google.com>
Date: Mon Feb 24 16:13:03 2020 +0000

usb: gadget: add raw-gadget interface

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1277ece2100000
final crash: https://syzkaller.appspot.com/x/report.txt?x=1177ece2100000
console output: https://syzkaller.appspot.com/x/log.txt?x=1677ece2100000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+31610284091be1bf04f4@syzkaller.appspotmail.com
Fixes: f2c2e717642c ("usb: gadget: add raw-gadget interface")

usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-1: Product: syz
usb 1-1: Manufacturer: syz
usb 1-1: SerialNumber: syz
usb 1-1: config 0 descriptor??
==================================================================
BUG: KASAN: slab-out-of-bounds in hex_string+0x416/0x520 lib/vsprintf.c:1144
Read of size 1 at addr ffff8880a6c1301b by task kworker/1:8/4076

CPU: 1 PID: 4076 Comm: kworker/1:8 Not tainted 5.7.0-rc6-syzkaller #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+0x1e9/0x30e lib/dump_stack.c:118
print_address_description+0x74/0x5c0 mm/kasan/report.c:382
printk+0x62/0x83 kernel/printk/printk.c:2081
__kasan_report+0x103/0x1a0 mm/kasan/report.c:511
hex_string+0x416/0x520 lib/vsprintf.c:1144
test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
hlock_class kernel/locking/lockdep.c:179 [inline]
mark_lock+0x102/0x1b00 kernel/locking/lockdep.c:3912
hex_string+0x416/0x520 lib/vsprintf.c:1144
kasan_report+0x4d/0x80 mm/kasan/common.c:625
test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
hlock_class kernel/locking/lockdep.c:179 [inline]
mark_lock+0x102/0x1b00 kernel/locking/lockdep.c:3912
hex_string+0x416/0x520 lib/vsprintf.c:1144
pointer+0x539/0x970 lib/vsprintf.c:2204
vsnprintf+0xbf4/0x1aa0 lib/vsprintf.c:2597
va_format lib/vsprintf.c:1659 [inline]
pointer+0x12d/0x970 lib/vsprintf.c:2232
vsnprintf+0xbf4/0x1aa0 lib/vsprintf.c:2597
vscnprintf+0x29/0x80 lib/vsprintf.c:2696
vprintk_store+0x4b/0x680 kernel/printk/printk.c:1942
vprintk_emit+0x128/0x3c0 kernel/printk/printk.c:2003
dev_vprintk_emit+0x494/0x512 drivers/base/core.c:3774
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0xb4/0xd0 kernel/locking/spinlock.c:191
__debug_check_no_obj_freed lib/debugobjects.c:977 [inline]
debug_check_no_obj_freed+0x592/0x640 lib/debugobjects.c:998
mark_held_locks kernel/locking/lockdep.c:3628 [inline]
__trace_hardirqs_on_caller kernel/locking/lockdep.c:3657 [inline]
lockdep_hardirqs_on+0x4a4/0x8a0 kernel/locking/lockdep.c:3702
dev_printk_emit+0x6a/0x8c drivers/base/core.c:3785
usb_control_msg+0x2f3/0x420 drivers/usb/core/message.c:159
_dev_info+0xb9/0xdb drivers/base/core.c:3843
dlfb_parse_vendor_descriptor drivers/video/fbdev/udlfb.c:1588 [inline]
dlfb_usb_probe+0x3ee/0x2080 drivers/video/fbdev/udlfb.c:1672
dlfb_parse_vendor_descriptor drivers/video/fbdev/udlfb.c:1589 [inline]
dlfb_usb_probe+0x443/0x2080 drivers/video/fbdev/udlfb.c:1672
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
_raw_spin_unlock_irqrestore+0x6f/0xd0 kernel/locking/spinlock.c:191
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0xb4/0xd0 kernel/locking/spinlock.c:191
__pm_runtime_set_status+0x89e/0xb50 drivers/base/power/runtime.c:1251
usb_probe_interface+0x614/0xac0 drivers/usb/core/driver.c:374
really_probe+0x761/0xf60 drivers/base/dd.c:524
driver_probe_device+0xe6/0x230 drivers/base/dd.c:697
coredump_store+0x90/0x90 drivers/base/dd.c:373
bus_for_each_drv+0x108/0x170 drivers/base/bus.c:431
__device_attach+0x20c/0x3a0 drivers/base/dd.c:870
bus_probe_device+0xb8/0x1f0 drivers/base/bus.c:491
device_add+0x14a4/0x1ba0 drivers/base/core.c:2529
device_add+0x1828/0x1ba0 drivers/base/core.c:2538
usb_set_configuration+0x19d2/0x1f20 drivers/usb/core/message.c:2032
usb_generic_driver_probe+0x82/0x140 drivers/usb/core/generic.c:241
usb_probe_device+0x12d/0x1d0 drivers/usb/core/driver.c:272
really_probe+0x761/0xf60 drivers/base/dd.c:524
driver_probe_device+0xe6/0x230 drivers/base/dd.c:697
coredump_store+0x90/0x90 drivers/base/dd.c:373
bus_for_each_drv+0x108/0x170 drivers/base/bus.c:431
__device_attach+0x20c/0x3a0 drivers/base/dd.c:870
bus_probe_device+0xb8/0x1f0 drivers/base/bus.c:491
device_add+0x14a4/0x1ba0 drivers/base/core.c:2529
device_add+0x1828/0x1ba0 drivers/base/core.c:2538
usb_new_device+0xcc3/0x1650 drivers/usb/core/hub.c:2554
hub_port_connect drivers/usb/core/hub.c:5208 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5348 [inline]
port_event drivers/usb/core/hub.c:5494 [inline]
hub_event+0x2823/0x4cb0 drivers/usb/core/hub.c:5576
lock_is_held include/linux/lockdep.h:406 [inline]
rcu_read_lock_sched_held+0x106/0x170 kernel/rcu/update.c:121
process_one_work+0x76e/0xfd0 kernel/workqueue.c:2268
worker_thread+0xa7f/0x1450 kernel/workqueue.c:2414
kthread+0x353/0x380 kernel/kthread.c:268
rcu_lock_release+0x20/0x20 include/linux/rcupdate.h:213
kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1247
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351

Allocated by task 4076:
save_stack mm/kasan/common.c:49 [inline]
set_track mm/kasan/common.c:57 [inline]
__kasan_kmalloc+0x114/0x160 mm/kasan/common.c:495
__do_kmalloc mm/slab.c:3656 [inline]
__kmalloc+0x24b/0x330 mm/slab.c:3665
kmalloc include/linux/slab.h:560 [inline]
usb_get_configuration+0x2d7/0x48e0 drivers/usb/core/config.c:919
usb_enumerate_device drivers/usb/core/hub.c:2387 [inline]
usb_new_device+0xf4/0x1650 drivers/usb/core/hub.c:2523
hub_port_connect drivers/usb/core/hub.c:5208 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5348 [inline]
port_event drivers/usb/core/hub.c:5494 [inline]
hub_event+0x2823/0x4cb0 drivers/usb/core/hub.c:5576
process_one_work+0x76e/0xfd0 kernel/workqueue.c:2268
worker_thread+0xa7f/0x1450 kernel/workqueue.c:2414
kthread+0x353/0x380 kernel/kthread.c:268
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351

Freed by task 5147:
save_stack mm/kasan/common.c:49 [inline]
set_track mm/kasan/common.c:57 [inline]
kasan_set_free_info mm/kasan/common.c:317 [inline]
__kasan_slab_free+0x125/0x190 mm/kasan/common.c:456
__cache_free mm/slab.c:3426 [inline]
kfree+0x10a/0x220 mm/slab.c:3757
tomoyo_check_open_permission+0x6e2/0x900 security/tomoyo/file.c:786
security_file_open+0x50/0xc0 security/security.c:1548
do_dentry_open+0x35d/0x10b0 fs/open.c:784
do_open fs/namei.c:3229 [inline]
path_openat+0x2790/0x38b0 fs/namei.c:3346
do_filp_open+0x191/0x3a0 fs/namei.c:3373
do_sys_openat2+0x463/0x770 fs/open.c:1148
do_sys_open fs/open.c:1164 [inline]
ksys_open include/linux/syscalls.h:1386 [inline]
__do_sys_open fs/open.c:1170 [inline]
__se_sys_open fs/open.c:1168 [inline]
__x64_sys_open+0x1af/0x1e0 fs/open.c:1168
do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
entry_SYSCALL_64_after_hwframe+0x49/0xb3

The buggy address belongs to the object at ffff8880a6c13000
which belongs to the cache kmalloc-32 of size 32
The buggy address is located 27 bytes inside of
32-byte region [ffff8880a6c13000, ffff8880a6c13020)
The buggy address belongs to the page:
page:ffffea00029b04c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a6c13fc1
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00025f7e88 ffffea0002a6ff48 ffff8880aa4001c0
raw: ffff8880a6c13fc1 ffff8880a6c13000 000000010000003e 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8880a6c12f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff8880a6c12f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880a6c13000: 00 00 00 03 fc fc fc fc 00 00 01 fc fc fc fc fc
^
ffff8880a6c13080: fb fb fb fb fc fc fc fc 00 00 01 fc fc fc fc fc
ffff8880a6c13100: 00 00 01 fc fc fc fc fc 00 00 01 fc fc fc fc fc
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

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