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BUG: KASAN: global-out-of-bounds in kobject_action_type lib/kobject_uevent.c:86 [inline]
BUG: KASAN: global-out-of-bounds in kobject_synth_uevent+0x79d/0x7d0 lib/kobject_uevent.c:200
Read of size 1 at addr ffffffff8d71057e by task syz.4.4576/25314

CPU: 3 UID: 0 PID: 25314 Comm: syz.4.4576 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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
 kobject_action_type lib/kobject_uevent.c:86 [inline]
 kobject_synth_uevent+0x79d/0x7d0 lib/kobject_uevent.c:200
 uevent_store+0x46/0x90 drivers/base/bus.c:723
 drv_attr_store+0x74/0xb0 drivers/base/bus.c:125
 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6af/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:79 [inline]
 __do_fast_syscall_32+0x13a/0x8b0 arch/x86/entry/syscall_32.c:291
 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:316
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf708efec
Code: Unable to access opcode bytes at 0xf708efc2.
RSP: 002b:00000000f547d50c EFLAGS: 00000292 ORIG_RAX: 0000000000000004
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000080000300
RDX: 000000000000003f RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

The buggy address belongs to the variable:
 uevent_helper_sysctl_table+0xde/0x2a0

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xd710
flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000002000 ffffea000035c408 ffffea000035c408 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffffffff8d710400: f9 f9 f9 f9 00 00 03 f9 f9 f9 f9 f9 00 f9 f9 f9
 ffffffff8d710480: f9 f9 f9 f9 00 00 00 00 00 00 00 f9 f9 f9 f9 f9
>ffffffff8d710500: 00 07 f9 f9 f9 f9 f9 f9 04 f9 f9 f9 f9 f9 f9 f9
                                                                ^
 ffffffff8d710580: 07 f9 f9 f9 f9 f9 f9 f9 07 f9 f9 f9 f9 f9 f9 f9
 ffffffff8d710600: 05 f9 f9 f9 f9 f9 f9 f9 07 f9 f9 f9 f9 f9 f9 f9
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