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Date:   Wed, 20 Jul 2022 11:03:24 -0700
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Message-ID: <000000000000d36e8705e4406a16@google.com>
Subject: Re: [syzbot] KASAN: use-after-free Read in usb_udc_uevent
From:   syzbot <syzbot+b0de012ceb1e2a97891b@syzkaller.appspotmail.com>
To:     andriy.shevchenko@linux.intel.com, balbi@kernel.org,
        gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
        linux-usb@vger.kernel.org, rogerq@ti.com,
        stern@rowland.harvard.edu, syzkaller-bugs@googlegroups.com,
        zhengdejin5@gmail.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

syzbot has found a reproducer for the following issue on:

HEAD commit:    cb71b93c2dc3 Add linux-next specific files for 20220628
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=172591aa080000
kernel config:  https://syzkaller.appspot.com/x/.config?x=badbc1adb2d582eb
dashboard link: https://syzkaller.appspot.com/bug?extid=b0de012ceb1e2a97891b
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=13ab4d62080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b0de012ceb1e2a97891b@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in usb_udc_uevent+0x11f/0x130 drivers/usb/gadget/udc/core.c:1732
Read of size 8 at addr ffff888078ce2050 by task udevd/2968

CPU: 1 PID: 2968 Comm: udevd Not tainted 5.19.0-rc4-next-20220628-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:317 [inline]
 print_report.cold+0x2ba/0x719 mm/kasan/report.c:433
 kasan_report+0xbe/0x1f0 mm/kasan/report.c:495
 usb_udc_uevent+0x11f/0x130 drivers/usb/gadget/udc/core.c:1732
 dev_uevent+0x290/0x770 drivers/base/core.c:2424
 uevent_show+0x1b8/0x380 drivers/base/core.c:2480
 dev_attr_show+0x4b/0x90 drivers/base/core.c:2183
 sysfs_kf_seq_show+0x219/0x3d0 fs/sysfs/file.c:59
 seq_read_iter+0x4f5/0x1280 fs/seq_file.c:230
 kernfs_fop_read_iter+0x506/0x6e0 fs/kernfs/file.c:235
 call_read_iter include/linux/fs.h:2182 [inline]
 new_sync_read+0x314/0x560 fs/read_write.c:401
 vfs_read+0x492/0x5d0 fs/read_write.c:482
 ksys_read+0x127/0x250 fs/read_write.c:620
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f996d1258fe
Code: c0 e9 e6 fe ff ff 50 48 8d 3d 0e c7 09 00 e8 c9 cf 01 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28
RSP: 002b:00007ffcfcbe6368 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000055ca13b297a0 RCX: 00007f996d1258fe
RDX: 0000000000001000 RSI: 000055ca13b5a4e0 RDI: 000000000000000c
RBP: 00007f996d1f2380 R08: 000000000000000c R09: 00007f996d1f5a60
R10: 0000000000000800 R11: 0000000000000246 R12: 000055ca13b297a0
R13: 0000000000000d68 R14: 00007f996d1f1780 R15: 0000000000000d68
 </TASK>

Allocated by task 4797:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:436 [inline]
 ____kasan_kmalloc mm/kasan/common.c:515 [inline]
 ____kasan_kmalloc mm/kasan/common.c:474 [inline]
 __kasan_kmalloc+0xa9/0xd0 mm/kasan/common.c:524
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:733 [inline]
 dev_new drivers/usb/gadget/legacy/raw_gadget.c:191 [inline]
 raw_open+0x87/0x500 drivers/usb/gadget/legacy/raw_gadget.c:385
 misc_open+0x376/0x4a0 drivers/char/misc.c:143
 chrdev_open+0x266/0x770 fs/char_dev.c:414
 do_dentry_open+0x4a1/0x11f0 fs/open.c:878
 do_open fs/namei.c:3520 [inline]
 path_openat+0x1c71/0x2930 fs/namei.c:3653
 do_filp_open+0x1aa/0x400 fs/namei.c:3680
 do_sys_openat2+0x16d/0x4c0 fs/open.c:1308
 do_sys_open fs/open.c:1324 [inline]
 __do_sys_openat fs/open.c:1340 [inline]
 __se_sys_openat fs/open.c:1335 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1335
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Freed by task 4797:
 kasan_save_stack+0x1e/0x40 mm/kasan/common.c:38
 kasan_set_track+0x21/0x30 mm/kasan/common.c:45
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:370
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free+0x166/0x1c0 mm/kasan/common.c:328
 kasan_slab_free include/linux/kasan.h:200 [inline]
 slab_free_hook mm/slub.c:1754 [inline]
 slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1780
 slab_free mm/slub.c:3534 [inline]
 kfree+0xe2/0x4d0 mm/slub.c:4562
 kref_put include/linux/kref.h:65 [inline]
 raw_release+0x219/0x290 drivers/usb/gadget/legacy/raw_gadget.c:424
 __fput+0x277/0x9d0 fs/file_table.c:317
 task_work_run+0xdd/0x1a0 kernel/task_work.c:177
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xaf1/0x29f0 kernel/exit.c:795
 do_group_exit+0xd2/0x2f0 kernel/exit.c:925
 get_signal+0x2542/0x2600 kernel/signal.c:2857
 arch_do_signal_or_restart+0x82/0x2300 arch/x86/kernel/signal.c:869
 exit_to_user_mode_loop kernel/entry/common.c:166 [inline]
 exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:294
 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

The buggy address belongs to the object at ffff888078ce2000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 80 bytes inside of
 4096-byte region [ffff888078ce2000, ffff888078ce3000)

The buggy address belongs to the physical page:
page:ffffea0001e33800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78ce0
head:ffffea0001e33800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000001 ffff888011842140
raw: 0000000000000000 0000000000040004 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3618, tgid 3618 (syz-executor.2), ts 66675676094, free_ts 28120915618
 prep_new_page mm/page_alloc.c:2535 [inline]
 get_page_from_freelist+0x210d/0x3a30 mm/page_alloc.c:4282
 __alloc_pages+0x1c7/0x510 mm/page_alloc.c:5506
 alloc_pages+0x1aa/0x310 mm/mempolicy.c:2280
 alloc_slab_page mm/slub.c:1824 [inline]
 allocate_slab+0x27e/0x3d0 mm/slub.c:1969
 new_slab mm/slub.c:2029 [inline]
 ___slab_alloc+0x89d/0xef0 mm/slub.c:3031
 __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3118
 slab_alloc_node mm/slub.c:3209 [inline]
 slab_alloc mm/slub.c:3251 [inline]
 kmem_cache_alloc_trace+0x323/0x3e0 mm/slub.c:3282
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:733 [inline]
 kobject_uevent_env+0x230/0x1640 lib/kobject_uevent.c:524
 netdev_queue_add_kobject net/core/net-sysfs.c:1677 [inline]
 netdev_queue_update_kobjects+0x3d1/0x4e0 net/core/net-sysfs.c:1718
 register_queue_kobjects net/core/net-sysfs.c:1779 [inline]
 netdev_register_kobject+0x330/0x400 net/core/net-sysfs.c:2019
 register_netdevice+0xd9d/0x15e0 net/core/dev.c:10065
 bond_newlink drivers/net/bonding/bond_netlink.c:560 [inline]
 bond_newlink+0x47/0xa0 drivers/net/bonding/bond_netlink.c:550
 rtnl_newlink_create net/core/rtnetlink.c:3363 [inline]
 __rtnl_newlink+0x1087/0x17e0 net/core/rtnetlink.c:3580
 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3593
 rtnetlink_rcv_msg+0x43a/0xc90 net/core/rtnetlink.c:6089
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2501
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1453 [inline]
 free_pcp_prepare+0x5e4/0xd20 mm/page_alloc.c:1503
 free_unref_page_prepare mm/page_alloc.c:3383 [inline]
 free_unref_page+0x19/0x4d0 mm/page_alloc.c:3479
 __unfreeze_partials+0x17c/0x1a0 mm/slub.c:2548
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x6a/0x170 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0xa2/0xc0 mm/kasan/common.c:446
 kasan_slab_alloc include/linux/kasan.h:224 [inline]
 slab_post_alloc_hook mm/slab.h:736 [inline]
 kmem_cache_alloc_bulk+0x383/0x730 mm/slub.c:3735
 mt_alloc_bulk lib/maple_tree.c:151 [inline]
 mas_alloc_nodes+0x2b0/0x6b0 lib/maple_tree.c:1244
 mas_preallocate+0xff/0x2d0 lib/maple_tree.c:5662
 __vma_adjust+0x226/0x1900 mm/mmap.c:765
 vma_adjust include/linux/mm.h:2678 [inline]
 __split_vma+0x295/0x530 mm/mmap.c:2305
 split_vma+0x9f/0xe0 mm/mmap.c:2335
 mprotect_fixup+0x746/0x960 mm/mprotect.c:613
 do_mprotect_pkey+0x70f/0xa80 mm/mprotect.c:781
 __do_sys_mprotect mm/mprotect.c:808 [inline]
 __se_sys_mprotect mm/mprotect.c:805 [inline]
 __x64_sys_mprotect+0x74/0xb0 mm/mprotect.c:805
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80

Memory state around the buggy address:
 ffff888078ce1f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888078ce1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888078ce2000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff888078ce2080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888078ce2100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================