[syzbot] [kernel?] KASAN: slab-use-after-free Read in class_register

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syzbot

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Apr 1, 2023, 4:12:53 AM4/1/23
to gre...@linuxfoundation.org, linux-...@vger.kernel.org, raf...@kernel.org, syzkall...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: 198925fae644 Add linux-next specific files for 20230329
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17f9a03ec80000
kernel config: https://syzkaller.appspot.com/x/.config?x=91e70627549fd509
dashboard link: https://syzkaller.appspot.com/bug?extid=41d665317c811d4d88aa
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=105d5a2ec80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11ab4895c80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/53c685bee82f/disk-198925fa.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/45e82baa3bc5/vmlinux-198925fa.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7c31fbc6acb9/bzImage-198925fa.xz

The issue was bisected to:

commit dcfbb67e48a2becfce7990386e985b9c45098ee5
Author: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Date: Fri Mar 24 10:01:31 2023 +0000

driver core: class: use lock_class_key already present in struct subsys_private

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=173f4ab9c80000
final oops: https://syzkaller.appspot.com/x/report.txt?x=14bf4ab9c80000
console output: https://syzkaller.appspot.com/x/log.txt?x=10bf4ab9c80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+41d665...@syzkaller.appspotmail.com
Fixes: dcfbb67e48a2 ("driver core: class: use lock_class_key already present in struct subsys_private")

usb 1-1: New USB device strings: Mfr=0, Product=106, SerialNumber=59
usb 1-1: Product: syz
usb 1-1: SerialNumber: syz
hub 1-1:250.228: bad descriptor, ignoring hub
hub: probe of 1-1:250.228 failed with error -5
==================================================================
BUG: KASAN: slab-use-after-free in lockdep_register_key+0x396/0x410 kernel/locking/lockdep.c:1231
Read of size 8 at addr ffff888020bbc360 by task kworker/1:2/2492

CPU: 1 PID: 2492 Comm: kworker/1:2 Not tainted 6.3.0-rc4-next-20230329-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
print_report mm/kasan/report.c:462 [inline]
kasan_report+0x11c/0x130 mm/kasan/report.c:572
lockdep_register_key+0x396/0x410 kernel/locking/lockdep.c:1231
class_register+0xed/0x530 drivers/base/class.c:172
class_create+0x99/0x100 drivers/base/class.c:249
init_usb_class drivers/usb/core/file.c:91 [inline]
usb_register_dev+0x4e7/0x860 drivers/usb/core/file.c:179
usblp_probe+0xc91/0x16d0 drivers/usb/class/usblp.c:1208
usb_probe_interface+0x30f/0x960 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:579 [inline]
really_probe+0x240/0xca0 drivers/base/dd.c:658
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:795
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:825
__device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:953
bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:457
__device_attach+0x1e4/0x4b0 drivers/base/dd.c:1025
bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
device_add+0x11c4/0x1c50 drivers/base/core.c:3611
usb_set_configuration+0x10ee/0x1af0 drivers/usb/core/message.c:2171
usb_generic_driver_probe+0xcf/0x130 drivers/usb/core/generic.c:238
usb_probe_device+0xd8/0x2c0 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:579 [inline]
really_probe+0x240/0xca0 drivers/base/dd.c:658
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:795
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:825
__device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:953
bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:457
__device_attach+0x1e4/0x4b0 drivers/base/dd.c:1025
bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
device_add+0x11c4/0x1c50 drivers/base/core.c:3611
usb_new_device+0xcb2/0x19d0 drivers/usb/core/hub.c:2575
hub_port_connect drivers/usb/core/hub.c:5407 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5551 [inline]
port_event drivers/usb/core/hub.c:5711 [inline]
hub_event+0x2d9e/0x4e40 drivers/usb/core/hub.c:5793
process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
process_scheduled_works kernel/workqueue.c:2468 [inline]
worker_thread+0x881/0x10c0 kernel/workqueue.c:2554
kthread+0x33e/0x440 kernel/kthread.c:379
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>

Allocated by task 2492:
kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:374 [inline]
____kasan_kmalloc mm/kasan/common.c:333 [inline]
__kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383
kmalloc include/linux/slab.h:559 [inline]
kzalloc include/linux/slab.h:680 [inline]
class_register+0x55/0x530 drivers/base/class.c:165
class_create+0x99/0x100 drivers/base/class.c:249
init_usb_class drivers/usb/core/file.c:91 [inline]
usb_register_dev+0x4e7/0x860 drivers/usb/core/file.c:179
usblp_probe+0xc91/0x16d0 drivers/usb/class/usblp.c:1208
usb_probe_interface+0x30f/0x960 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:579 [inline]
really_probe+0x240/0xca0 drivers/base/dd.c:658
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:795
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:825
__device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:953
bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:457
__device_attach+0x1e4/0x4b0 drivers/base/dd.c:1025
bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
device_add+0x11c4/0x1c50 drivers/base/core.c:3611
usb_set_configuration+0x10ee/0x1af0 drivers/usb/core/message.c:2171
usb_generic_driver_probe+0xcf/0x130 drivers/usb/core/generic.c:238
usb_probe_device+0xd8/0x2c0 drivers/usb/core/driver.c:293
call_driver_probe drivers/base/dd.c:579 [inline]
really_probe+0x240/0xca0 drivers/base/dd.c:658
__driver_probe_device+0x1df/0x4d0 drivers/base/dd.c:795
driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:825
__device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:953
bus_for_each_drv+0x149/0x1d0 drivers/base/bus.c:457
__device_attach+0x1e4/0x4b0 drivers/base/dd.c:1025
bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532
device_add+0x11c4/0x1c50 drivers/base/core.c:3611
usb_new_device+0xcb2/0x19d0 drivers/usb/core/hub.c:2575
hub_port_connect drivers/usb/core/hub.c:5407 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5551 [inline]
port_event drivers/usb/core/hub.c:5711 [inline]
hub_event+0x2d9e/0x4e40 drivers/usb/core/hub.c:5793
process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
process_scheduled_works kernel/workqueue.c:2468 [inline]
worker_thread+0x881/0x10c0 kernel/workqueue.c:2554
kthread+0x33e/0x440 kernel/kthread.c:379
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

Freed by task 2492:
kasan_save_stack+0x22/0x40 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
kasan_save_free_info+0x2e/0x40 mm/kasan/generic.c:521
____kasan_slab_free mm/kasan/common.c:236 [inline]
____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200
kasan_slab_free include/linux/kasan.h:162 [inline]
slab_free_hook mm/slub.c:1781 [inline]
slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1807
slab_free mm/slub.c:3787 [inline]
__kmem_cache_free+0xaf/0x2d0 mm/slub.c:3800
kobject_cleanup lib/kobject.c:683 [inline]
kobject_release lib/kobject.c:714 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1c2/0x4d0 lib/kobject.c:731
kset_unregister+0x64/0x80 lib/kobject.c:880
class_destroy+0x3c/0x50 drivers/base/class.c:273
release_usb_class drivers/usb/core/file.c:108 [inline]
kref_put include/linux/kref.h:65 [inline]
destroy_usb_class drivers/usb/core/file.c:116 [inline]
usb_deregister_dev+0x274/0x320 drivers/usb/core/file.c:245
usblp_disconnect+0x4a/0x330 drivers/usb/class/usblp.c:1396
usb_unbind_interface+0x1dc/0x8e0 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:569 [inline]
device_remove+0x11f/0x170 drivers/base/dd.c:561
__device_release_driver drivers/base/dd.c:1267 [inline]
device_release_driver_internal+0x443/0x610 drivers/base/dd.c:1290
bus_remove_device+0x22c/0x420 drivers/base/bus.c:574
device_del+0x48a/0xb80 drivers/base/core.c:3797
usb_disable_device+0x35a/0x7b0 drivers/usb/core/message.c:1420
usb_disconnect+0x2db/0x8a0 drivers/usb/core/hub.c:2238
hub_port_connect drivers/usb/core/hub.c:5246 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5551 [inline]
port_event drivers/usb/core/hub.c:5711 [inline]
hub_event+0x1fbf/0x4e40 drivers/usb/core/hub.c:5793
process_one_work+0x99a/0x15e0 kernel/workqueue.c:2405
process_scheduled_works kernel/workqueue.c:2468 [inline]
worker_thread+0x881/0x10c0 kernel/workqueue.c:2554
kthread+0x33e/0x440 kernel/kthread.c:379
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

The buggy address belongs to the object at ffff888020bbc000
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 864 bytes inside of
freed 1024-byte region [ffff888020bbc000, ffff888020bbc400)

The buggy address belongs to the physical page:
page:ffffea000082ee00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x20bb8
head:ffffea000082ee00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000010200 ffff888012441dc0 ffffea0001dcf600 dead000000000002
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 46, tgid 46 (kworker/u4:3), ts 9746960068, free_ts 0
prep_new_page mm/page_alloc.c:1729 [inline]
get_page_from_freelist+0xf75/0x2aa0 mm/page_alloc.c:3493
__alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:4759
__alloc_pages_node include/linux/gfp.h:237 [inline]
alloc_slab_page mm/slub.c:1853 [inline]
allocate_slab+0xa7/0x380 mm/slub.c:1998
new_slab mm/slub.c:2051 [inline]
___slab_alloc+0xa91/0x1400 mm/slub.c:3193
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3292
__slab_alloc_node mm/slub.c:3345 [inline]
slab_alloc_node mm/slub.c:3442 [inline]
__kmem_cache_alloc_node+0x136/0x320 mm/slub.c:3491
kmalloc_node_trace+0x21/0xd0 mm/slab_common.c:1070
kmalloc_node include/linux/slab.h:575 [inline]
kzalloc_node include/linux/slab.h:691 [inline]
blk_mq_alloc_hctx block/blk-mq.c:3628 [inline]
blk_mq_alloc_and_init_hctx+0x6bc/0x11d0 block/blk-mq.c:4105
blk_mq_realloc_hw_ctxs+0x47d/0x5e0 block/blk-mq.c:4138
blk_mq_init_allocated_queue+0x299/0x1280 block/blk-mq.c:4191
blk_mq_init_queue_data block/blk-mq.c:4010 [inline]
blk_mq_init_queue+0x88/0xf0 block/blk-mq.c:4020
scsi_alloc_sdev+0x852/0xd60 drivers/scsi/scsi_scan.c:335
scsi_probe_and_add_lun+0x1506/0x2670 drivers/scsi/scsi_scan.c:1187
__scsi_scan_target+0x249/0xe50 drivers/scsi/scsi_scan.c:1673
scsi_scan_channel drivers/scsi/scsi_scan.c:1761 [inline]
scsi_scan_channel+0x148/0x1e0 drivers/scsi/scsi_scan.c:1737
scsi_scan_host_selected+0x2e3/0x3f0 drivers/scsi/scsi_scan.c:1790
page_owner free stack trace missing

Memory state around the buggy address:
ffff888020bbc200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888020bbc280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888020bbc300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888020bbc380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888020bbc400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
This report 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 syzk...@googlegroups.com.

syzbot will keep track of this issue. 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 issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

Greg KH

unread,
Apr 1, 2023, 4:27:22 AM4/1/23
to syzbot, linux-...@vger.kernel.org, raf...@kernel.org, syzkall...@googlegroups.com
Ah, I forgot to unregister the lock, let me go fix this up, nice find
bot!


Greg KH

unread,
Apr 1, 2023, 5:06:15 AM4/1/23
to syzbot, linux-...@vger.kernel.org, raf...@kernel.org, syzkall...@googlegroups.com
On Sat, Apr 01, 2023 at 01:12:51AM -0700, syzbot wrote:
Reference: https://syzkaller.appspot.com/bug?extid=41d665317c811d4d88aa

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git/ driver-core-next


diff --git a/drivers/base/class.c b/drivers/base/class.c
index 2991936c80db..ac1808d1a2e8 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -103,6 +103,7 @@ static void class_release(struct kobject *kobj)
pr_debug("class '%s' does not have a release() function, "
"be careful\n", class->name);

+ lockdep_unregister_key(&cp->lock_key);
kfree(cp);
}


syzbot

unread,
Apr 1, 2023, 5:29:23 AM4/1/23
to gre...@linuxfoundation.org, linux-...@vger.kernel.org, raf...@kernel.org, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+41d665...@syzkaller.appspotmail.com

Tested on:

commit: 980c0561 driver core: make sysfs_dev_char_kobj static
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git/ driver-core-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1188bdd1c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=495034798c39316a
dashboard link: https://syzkaller.appspot.com/bug?extid=41d665317c811d4d88aa
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=115da421c80000

Note: testing is done by a robot and is best-effort only.
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