Re: [syzbot] KASAN: slab-use-after-free Read in vhci_send_cmd_submit

[syzbot <syzbot+ecbb1750082f7528b507@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in vhci_send_cmd_submit

==================================================================
BUG: KASAN: slab-use-after-free in vhci_send_cmd_submit+0xed2/0x10c0 drivers/usb/usbip/vhci_tx.c:91
Read of size 4 at addr ffff88802ae62784 by task vhci_tx/6047

CPU: 0 UID: 0 PID: 6047 Comm: vhci_tx Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 vhci_send_cmd_submit+0xed2/0x10c0 drivers/usb/usbip/vhci_tx.c:91
 vhci_tx_loop+0xff/0x460 drivers/usb/usbip/vhci_tx.c:241
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 6032:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5337 [inline]
 __kmalloc_noprof+0x324/0x820 mm/slub.c:5362
 _kmalloc_noprof include/linux/slab.h:992 [inline]
 usb_alloc_urb+0x66/0xa0 drivers/usb/core/urb.c:75
 alloc_async drivers/usb/core/devio.c:408 [inline]
 proc_do_submiturb+0x741/0x3820 drivers/usb/core/devio.c:1781
 proc_submiturb drivers/usb/core/devio.c:2003 [inline]
 usbdev_do_ioctl drivers/usb/core/devio.c:2703 [inline]
 usbdev_ioctl+0x2ae7/0x3a90 drivers/usb/core/devio.c:2827
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6032:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2678 [inline]
 slab_free mm/slub.c:6372 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6687
 urb_destroy drivers/usb/core/urb.c:27 [inline]
 kref_put include/linux/kref.h:65 [inline]
 usb_free_urb.part.0+0xa5/0x110 drivers/usb/core/urb.c:96
 usb_free_urb+0x1f/0x30 drivers/usb/core/urb.c:95
 free_async+0x37d/0x570 drivers/usb/core/devio.c:436
 proc_reapurbnonblock drivers/usb/core/devio.c:2130 [inline]
 usbdev_do_ioctl drivers/usb/core/devio.c:2622 [inline]
 usbdev_ioctl+0x2e7/0x3a90 drivers/usb/core/devio.c:2827
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802ae62700
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 132 bytes inside of
 freed 192-byte region [ffff88802ae62700, ffff88802ae627c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2ae62
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801c0423c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 9072505480
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x110d/0x35b0 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x2eb/0x3300 mm/page_alloc.c:5436
 alloc_slab_page mm/slub.c:3267 [inline]
 allocate_slab mm/slub.c:3382 [inline]
 new_slab+0xa5/0x640 mm/slub.c:3428
 refill_objects+0xe3/0x410 mm/slub.c:7305
 refill_sheaf mm/slub.c:2805 [inline]
 __pcs_replace_empty_main+0x372/0x680 mm/slub.c:4677
 alloc_from_pcs mm/slub.c:4775 [inline]
 slab_alloc_node mm/slub.c:4907 [inline]
 __do_kmalloc_node mm/slub.c:5336 [inline]
 __kmalloc_noprof+0x66b/0x820 mm/slub.c:5362
 _kmalloc_noprof include/linux/slab.h:992 [inline]
 _kzalloc_noprof include/linux/slab.h:1309 [inline]
 new_dir fs/proc/proc_sysctl.c:965 [inline]
 get_subdir fs/proc/proc_sysctl.c:1009 [inline]
 sysctl_mkdir_p fs/proc/proc_sysctl.c:1319 [inline]
 __register_sysctl_table+0xbe4/0x1650 fs/proc/proc_sysctl.c:1394
 register_net_sysctl_sz+0x325/0x420 net/sysctl_net.c:172
 neigh_sysctl_register+0x326/0x660 net/core/neighbour.c:3915
 devinet_sysctl_register+0xb6/0x210 net/ipv4/devinet.c:2781
 inetdev_init+0x2b8/0x570 net/ipv4/devinet.c:291
 inetdev_event+0x827/0x17f0 net/ipv4/devinet.c:1590
 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2275
 call_netdevice_notifiers_extack net/core/dev.c:2313 [inline]
 call_netdevice_notifiers net/core/dev.c:2327 [inline]
 register_netdevice+0x1998/0x25a0 net/core/dev.c:11541
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88802ae62680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88802ae62700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802ae62780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                   ^
 ffff88802ae62800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802ae62880: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


Tested on:

commit:         818bebeb drm/xe: Don't hand out the flat CCS storage a..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=148c0179580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ccca94d2c01b9e78
dashboard link: https://syzkaller.appspot.com/bug?extid=ecbb1750082f7528b507
compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
patch:          https://syzkaller.appspot.com/x/patch.diff?x=16c30415580000