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BUG: KASAN: stack-out-of-bounds in ft260_smbus_write+0x156/0x2f0 drivers/hid/hid-ft260.c:486
Read of size 42 at addr ffffc9000ce27d21 by task syz.0.163/6206

CPU: 0 UID: 0 PID: 6206 Comm: syz.0.163 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:200
 __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
 ft260_smbus_write+0x156/0x2f0 drivers/hid/hid-ft260.c:486
 ft260_smbus_xfer+0x8bc/0xdd0 drivers/hid/hid-ft260.c:-1
 __i2c_smbus_xfer+0x557/0x1e20 drivers/i2c/i2c-core-smbus.c:591
 i2c_smbus_xfer+0x1f4/0x310 drivers/i2c/i2c-core-smbus.c:546
 i2cdev_ioctl_smbus+0x3db/0x750 drivers/i2c/i2c-dev.c:389
 i2cdev_ioctl+0x5d3/0x820 drivers/i2c/i2c-dev.c:478
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f97ac58f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcc9dab998 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f97ac7e5fa0 RCX: 00007f97ac58f749
RDX: 0000200000000200 RSI: 0000000000000720 RDI: 0000000000000004
RBP: 00007f97ac613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f97ac7e5fa0 R14: 00007f97ac7e5fa0 R15: 0000000000000003
 </TASK>

The buggy address belongs to stack of task syz.0.163/6206
 and is located at offset 33 in frame:
 i2cdev_ioctl_smbus+0x0/0x750 drivers/i2c/i2c-dev.c:317

This frame has 1 object:
 [32, 66) 'temp'

The buggy address belongs to a 8-page vmalloc region starting at 0xffffc9000ce20000 allocated at copy_process+0x4e8/0x3ba0 kernel/fork.c:2049
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x27477
memcg:ffff888031c54a82
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 ffffea00009d1dc8 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff ffff888031c54a82
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x29c2(GFP_NOWAIT|__GFP_HIGHMEM|__GFP_IO|__GFP_FS|__GFP_ZERO), pid 5945, tgid 5945 (syz-executor), ts 175695068797, free_ts 175571170414
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x23d/0x2a0 mm/page_alloc.c:1887
 prep_new_page mm/page_alloc.c:1895 [inline]
 get_page_from_freelist+0x23a5/0x2440 mm/page_alloc.c:3948
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5236
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486
 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline]
 alloc_pages_noprof+0xa9/0x190 mm/mempolicy.c:2577
 vm_area_alloc_pages mm/vmalloc.c:3662 [inline]
 __vmalloc_area_node mm/vmalloc.c:3876 [inline]
 __vmalloc_node_range_noprof+0x795/0x16a0 mm/vmalloc.c:4064
 __vmalloc_node_noprof+0xc2/0x110 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:354 [inline]
 dup_task_struct+0x228/0x9a0 kernel/fork.c:923
 copy_process+0x4e8/0x3ba0 kernel/fork.c:2049
 kernel_clone+0x21e/0x820 kernel/fork.c:2648
 __do_sys_clone kernel/fork.c:2789 [inline]
 __se_sys_clone kernel/fork.c:2773 [inline]
 __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2773
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 6195 tgid 6195 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1436 [inline]
 __free_frozen_pages+0xb99/0xd10 mm/page_alloc.c:2976
 discard_slab mm/slub.c:3580 [inline]
 __put_partials+0x146/0x170 mm/slub.c:4120
 __slab_free+0x294/0x320 mm/slub.c:6193
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:5187 [inline]
 slab_alloc_node mm/slub.c:5500 [inline]
 __do_kmalloc_node mm/slub.c:5893 [inline]
 __kmalloc_noprof+0x3cf/0x800 mm/slub.c:5906
 kmalloc_noprof include/linux/slab.h:972 [inline]
 tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_number_perm+0x1e8/0x5a0 security/tomoyo/file.c:728
 security_file_ioctl+0xcb/0x2d0 security/security.c:2435
 __do_sys_ioctl fs/ioctl.c:591 [inline]
 __se_sys_ioctl+0x47/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffffc9000ce27c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000ce27c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc9000ce27d00: f1 f1 f1 f1 00 00 00 00 02 f3 f3 f3 f3 f3 f3 f3
                                           ^
 ffffc9000ce27d80: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
 ffffc9000ce27e00: 04 f2 00 00 f2 f2 00 00 f3 f3 f3 f3 00 00 00 00
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