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BUG: KASAN: use-after-free in dev_uevent+0x521/0x540 drivers/base/core.c:1888
Read of size 8 at addr ffff88809436c098 by task systemd-udevd/24472

CPU: 0 PID: 24472 Comm: systemd-udevd Not tainted 5.9.0-syzkaller #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+0x198/0x1fd lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 dev_uevent+0x521/0x540 drivers/base/core.c:1888
 uevent_show+0x1bb/0x380 drivers/base/core.c:1959
 dev_attr_show+0x4b/0x90 drivers/base/core.c:1663
 sysfs_kf_seq_show+0x1f8/0x400 fs/sysfs/file.c:60
 seq_read+0x432/0x1070 fs/seq_file.c:208
 kernfs_fop_read+0xe9/0x590 fs/kernfs/file.c:251
 vfs_read+0x1df/0x5a0 fs/read_write.c:479
 ksys_read+0x12d/0x250 fs/read_write.c:615
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f7c70320910
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:00007fffa5332628 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000055f72dba1d90 RCX: 00007f7c70320910
RDX: 0000000000001000 RSI: 000055f72dba7490 RDI: 0000000000000007
RBP: 00007f7c705db440 R08: 00007f7c705df1f8 R09: 0000000000001010
R10: 000055f72dba1d90 R11: 0000000000000246 R12: 0000000000001000
R13: 0000000000000d68 R14: 000055f72dba7490 R15: 00007f7c705da900

Allocated by task 24404:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
 kmem_cache_alloc_trace+0x174/0x300 mm/slab.c:3554
 kmalloc include/linux/slab.h:554 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 dev_new drivers/usb/gadget/legacy/raw_gadget.c:182 [inline]
 raw_open+0x8d/0x4d0 drivers/usb/gadget/legacy/raw_gadget.c:372
 misc_open+0x372/0x4a0 drivers/char/misc.c:141
 chrdev_open+0x266/0x770 fs/char_dev.c:414
 do_dentry_open+0x4b9/0x11b0 fs/open.c:817
 do_open fs/namei.c:3251 [inline]
 path_openat+0x1b9a/0x2730 fs/namei.c:3368
 do_filp_open+0x17e/0x3c0 fs/namei.c:3395
 do_sys_openat2+0x16d/0x420 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_open fs/open.c:1192 [inline]
 __se_sys_open fs/open.c:1188 [inline]
 __x64_sys_open+0x119/0x1c0 fs/open.c:1188
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 24403:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
 __cache_free mm/slab.c:3422 [inline]
 kfree+0x10e/0x2b0 mm/slab.c:3760
 kref_put include/linux/kref.h:65 [inline]
 raw_release+0x218/0x290 drivers/usb/gadget/legacy/raw_gadget.c:411
 __fput+0x285/0x920 fs/file_table.c:281
 task_work_run+0xdd/0x190 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:165 [inline]
 exit_to_user_mode_prepare+0x1e1/0x200 kernel/entry/common.c:192
 syscall_exit_to_user_mode+0x7e/0x2e0 kernel/entry/common.c:267
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88809436c000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 152 bytes inside of
 4096-byte region [ffff88809436c000, ffff88809436d000)
The buggy address belongs to the page:
page:0000000023d8ed39 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9436c
head:0000000023d8ed39 order:1 compound_mapcount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea0002a33708 ffffea00029cc108 ffff8880aa040900
raw: 0000000000000000 ffff88809436c000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809436bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809436c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88809436c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88809436c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809436c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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