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BUG: KASAN: use-after-free in dev_uevent+0x712/0x780 drivers/base/core.c:2278
Read of size 8 at addr ffff88802dc8c098 by task systemd-udevd/3251

CPU: 0 PID: 3251 Comm: systemd-udevd Not tainted 5.13.0-rc2-next-20210518-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x13e/0x1d6 lib/dump_stack.c:129
 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
 dev_uevent+0x712/0x780 drivers/base/core.c:2278
 uevent_show+0x1bb/0x390 drivers/base/core.c:2349
 dev_attr_show+0x4b/0x90 drivers/base/core.c:2051
 sysfs_kf_seq_show+0x1f8/0x400 fs/sysfs/file.c:61
 seq_read_iter+0x4d3/0x1220 fs/seq_file.c:227
 kernfs_fop_read_iter+0x44f/0x5f0 fs/kernfs/file.c:241
 call_read_iter include/linux/fs.h:2108 [inline]
 new_sync_read+0x41e/0x6e0 fs/read_write.c:415
 vfs_read+0x35c/0x570 fs/read_write.c:496
 ksys_read+0x12d/0x250 fs/read_write.c:634
 do_syscall_64+0x31/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fbb9a32f910
Code: b6 fe ff ff 48 8d 3d 0f be 08 00 48 83 ec 08 e8 06 db 01 00 66 0f 1f 44 00 00 83 3d f9 2d 2c 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 de 9b 01 00 48 89 04 24
RSP: 002b:00007ffdb39ac7e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000556127366be0 RCX: 00007fbb9a32f910
RDX: 0000000000001000 RSI: 0000556127362250 RDI: 0000000000000007
RBP: 00007fbb9a5ea440 R08: 00007fbb9a5ee1d8 R09: 0000000000001010
R10: 0000556127366be0 R11: 0000000000000246 R12: 0000000000001000
R13: 0000000000000d68 R14: 0000556127362250 R15: 00007fbb9a5e9900

Allocated by task 3205:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:431 [inline]
 ____kasan_kmalloc mm/kasan/common.c:510 [inline]
 ____kasan_kmalloc mm/kasan/common.c:469 [inline]
 __kasan_kmalloc+0x9b/0xd0 mm/kasan/common.c:519
 kmalloc include/linux/slab.h:590 [inline]
 kzalloc include/linux/slab.h:720 [inline]
 dev_new drivers/usb/gadget/legacy/raw_gadget.c:183 [inline]
 raw_open+0x8d/0x4d0 drivers/usb/gadget/legacy/raw_gadget.c:373
 misc_open+0x372/0x4a0 drivers/char/misc.c:141
 chrdev_open+0x266/0x770 fs/char_dev.c:414
 do_dentry_open+0x4b9/0x11c0 fs/open.c:826
 do_open fs/namei.c:3361 [inline]
 path_openat+0x1c09/0x27d0 fs/namei.c:3494
 do_filp_open+0x190/0x3d0 fs/namei.c:3521
 do_sys_openat2+0x16d/0x420 fs/open.c:1196
 do_sys_open fs/open.c:1212 [inline]
 __do_sys_openat fs/open.c:1228 [inline]
 __se_sys_openat fs/open.c:1223 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1223
 do_syscall_64+0x31/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 3204:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357
 ____kasan_slab_free mm/kasan/common.c:363 [inline]
 ____kasan_slab_free mm/kasan/common.c:328 [inline]
 __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:371
 kasan_slab_free include/linux/kasan.h:212 [inline]
 slab_free_hook mm/slub.c:1623 [inline]
 slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1648
 slab_free mm/slub.c:3208 [inline]
 kfree+0xeb/0x650 mm/slub.c:4274
 kref_put include/linux/kref.h:65 [inline]
 raw_release+0x218/0x290 drivers/usb/gadget/legacy/raw_gadget.c:412
 __fput+0x288/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0xbfc/0x2a70 kernel/exit.c:826
 do_group_exit+0x125/0x310 kernel/exit.c:923
 __do_sys_exit_group kernel/exit.c:934 [inline]
 __se_sys_exit_group kernel/exit.c:932 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:932
 do_syscall_64+0x31/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff88802dc8c000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 152 bytes inside of
 4096-byte region [ffff88802dc8c000, ffff88802dc8d000)
The buggy address belongs to the page:
page:ffffea0000b72200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2dc88
head:ffffea0000b72200 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888011042140
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 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4858, ts 363165571727, free_ts 363129945771
 prep_new_page mm/page_alloc.c:2377 [inline]
 get_page_from_freelist+0x125c/0x2ed0 mm/page_alloc.c:4038
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5239
 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2272
 alloc_slab_page mm/slub.c:1686 [inline]
 allocate_slab+0x2c2/0x4c0 mm/slub.c:1826
 new_slab mm/slub.c:1889 [inline]
 new_slab_objects mm/slub.c:2635 [inline]
 ___slab_alloc+0x4ba/0x820 mm/slub.c:2798
 __slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2838
 slab_alloc_node mm/slub.c:2920 [inline]
 slab_alloc mm/slub.c:2962 [inline]
 __kmalloc+0x312/0x330 mm/slub.c:4112
 kmalloc include/linux/slab.h:595 [inline]
 tomoyo_realpath_from_path+0xc3/0x620 security/tomoyo/realpath.c:254
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x21b/0x400 security/tomoyo/file.c:822
 security_inode_getattr+0xcf/0x140 security/security.c:1332
 vfs_getattr fs/stat.c:139 [inline]
 vfs_statx+0x164/0x390 fs/stat.c:207
 vfs_fstatat fs/stat.c:225 [inline]
 vfs_lstat include/linux/fs.h:3384 [inline]
 __do_sys_newlstat+0x91/0x110 fs/stat.c:380
 do_syscall_64+0x31/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1305 [inline]
 __free_pages_ok+0x4cb/0xf30 mm/page_alloc.c:1586
 unfreeze_partials+0x17c/0x1d0 mm/slub.c:2416
 put_cpu_partial+0x13d/0x230 mm/slub.c:2452
 qlink_free mm/kasan/quarantine.c:146 [inline]
 qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165
 kasan_quarantine_reduce+0x180/0x200 mm/kasan/quarantine.c:272
 __kasan_slab_alloc+0x8e/0xa0 mm/kasan/common.c:441
 kasan_slab_alloc include/linux/kasan.h:236 [inline]
 slab_post_alloc_hook mm/slab.h:512 [inline]
 slab_alloc_node mm/slub.c:2954 [inline]
 slab_alloc mm/slub.c:2962 [inline]
 __kmalloc+0x1f4/0x330 mm/slub.c:4112
 kmalloc include/linux/slab.h:595 [inline]
 tomoyo_realpath_from_path+0xc3/0x620 security/tomoyo/realpath.c:254
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x21b/0x400 security/tomoyo/file.c:822
 security_inode_getattr+0xcf/0x140 security/security.c:1332
 vfs_getattr fs/stat.c:139 [inline]
 vfs_fstat+0x43/0xb0 fs/stat.c:164
 __do_sys_newfstat+0x81/0x100 fs/stat.c:404
 do_syscall_64+0x31/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Memory state around the buggy address:
 ffff88802dc8bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802dc8c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802dc8c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88802dc8c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802dc8c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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