KASAN: slab-out-of-bounds Read in read_descriptors

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    22be26f7 usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=17bf83e8e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=387eccb7ac68ec5
dashboard link: https://syzkaller.appspot.com/bug?extid=11eed0a63c4f31acd096
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)

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+11eed0a63c4f31acd096@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: slab-out-of-bounds in read_descriptors+0x256/0x270  
drivers/usb/core/sysfs.c:903
Read of size 8 at addr ffff8881ce6e4350 by task udevd/9454

CPU: 1 PID: 9454 Comm: udevd Not tainted 5.4.0-rc3+ #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+0xca/0x13e lib/dump_stack.c:113
 print_address_description.constprop.0+0x36/0x50 mm/kasan/report.c:374
 __kasan_report.cold+0x1a/0x33 mm/kasan/report.c:506
 kasan_report+0xe/0x20 mm/kasan/common.c:634
 read_descriptors+0x256/0x270 drivers/usb/core/sysfs.c:903
 sysfs_kf_bin_read+0x196/0x270 fs/sysfs/file.c:99
 kernfs_file_direct_read fs/kernfs/file.c:213 [inline]
 kernfs_fop_read+0x2eb/0x560 fs/kernfs/file.c:253
 __vfs_read+0x76/0x100 fs/read_write.c:425
 vfs_read+0x1ea/0x430 fs/read_write.c:461
 ksys_read+0x127/0x250 fs/read_write.c:587
 do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f10f2702310
Code: 73 01 c3 48 8b 0d 28 4b 2b 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb  
ea 90 90 83 3d e5 a2 2b 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff  
ff 73 31 c3 48 83 ec 08 e8 6e 8a 01 00 48 89 04 24
RSP: 002b:00007ffd6a810e48 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007f10f2702310
RDX: 0000000000010011 RSI: 00007ffd6a810e80 RDI: 0000000000000005
RBP: 000000000174e640 R08: 000000000000000c R09: 75642f6d726f6674
R10: 2e6463685f796d6d R11: 0000000000000246 R12: 00007ffd6a821590
R13: 0000000001741250 R14: 0000000000000000 R15: 00000000017421c0

Allocated by task 22:
 save_stack+0x1b/0x80 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc mm/kasan/common.c:510 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:483
 kmalloc include/linux/slab.h:561 [inline]
 kzalloc include/linux/slab.h:690 [inline]
 usb_get_configuration+0x184/0x3050 drivers/usb/core/config.c:825
 usb_enumerate_device drivers/usb/core/hub.c:2369 [inline]
 usb_new_device+0xd3/0x160 drivers/usb/core/hub.c:2505
 hub_port_connect drivers/usb/core/hub.c:5183 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5323 [inline]
 port_event drivers/usb/core/hub.c:5469 [inline]
 hub_event+0x1dd0/0x37e0 drivers/usb/core/hub.c:5551
 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
 worker_thread+0x96/0xe20 kernel/workqueue.c:2415
 kthread+0x318/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 2807:
 save_stack+0x1b/0x80 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 kasan_set_free_info mm/kasan/common.c:332 [inline]
 __kasan_slab_free+0x130/0x180 mm/kasan/common.c:471
 slab_free_hook mm/slub.c:1424 [inline]
 slab_free_freelist_hook mm/slub.c:1475 [inline]
 slab_free mm/slub.c:3018 [inline]
 kfree+0xe4/0x320 mm/slub.c:3967
 usb_set_configuration+0xba8/0x1670 drivers/usb/core/message.c:1962
 generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
 usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
 really_probe+0x281/0x6d0 drivers/base/dd.c:548
 driver_probe_device+0x104/0x210 drivers/base/dd.c:721
 __device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
 bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
 __device_attach+0x217/0x360 drivers/base/dd.c:894
 bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
 device_add+0xae6/0x16f0 drivers/base/core.c:2201
 usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2536
 hub_port_connect drivers/usb/core/hub.c:5183 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5323 [inline]
 port_event drivers/usb/core/hub.c:5469 [inline]
 hub_event+0x1dd0/0x37e0 drivers/usb/core/hub.c:5551
 process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
 worker_thread+0x96/0xe20 kernel/workqueue.c:2415
 kthread+0x318/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8881ce6e4348
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes to the right of
 8-byte region [ffff8881ce6e4348, ffff8881ce6e4350)
The buggy address belongs to the page:
page:ffffea000739b900 refcount:1 mapcount:0 mapping:ffff8881da003900  
index:0x0
flags: 0x200000000000200(slab)
raw: 0200000000000200 ffffea0007632e40 0000000a0000000a ffff8881da003900
raw: 0000000000000000 0000000000aa00aa 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881ce6e4200: fc fc fb fc fc fb fc fc fb fc fc fb fc fc fb fc
 ffff8881ce6e4280: fc fb fc fc fb fc fc fb fc fc fb fc fc fb fc fc
> ffff8881ce6e4300: fb fc fc fb fc fc fb fc fc 00 fc fc fb fc fc fb
                                                 ^
 ffff8881ce6e4380: fc fc fb fc fc fb fc fc fb fc fc fb fc fc fb fc
 ffff8881ce6e4400: fc fb fc fc fb fc fc fb fc fc fb fc fc fb fc fc
==================================================================


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