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BUG: KASAN: stack-out-of-bounds in ft260_smbus_write+0x1e3/0x250 drivers/hid/hid-ft260.c:486
Read of size 42 at addr ffffc90003dffd79 by task syz.4.22/6683

CPU: 0 UID: 0 PID: 6683 Comm: syz.4.22 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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+0x156/0x4c9 mm/kasan/report.c:482
 kasan_report+0xdf/0x1a0 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:186 [inline]
 kasan_check_range+0x10f/0x1e0 mm/kasan/generic.c:200
 __asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105
 ft260_smbus_write+0x1e3/0x250 drivers/hid/hid-ft260.c:486
 ft260_smbus_xfer+0x222/0x600 drivers/hid/hid-ft260.c:736
 __i2c_smbus_xfer+0x4c3/0xf10 drivers/i2c/i2c-core-smbus.c:591
 i2c_smbus_xfer+0x185/0x3c0 drivers/i2c/i2c-core-smbus.c:546
 i2cdev_ioctl_smbus+0x233/0xac0 drivers/i2c/i2c-dev.c:389
 i2cdev_ioctl+0x3cf/0x830 drivers/i2c/i2c-dev.c:478
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcb3e19aef9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcb3ef99028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fcb3e405fa0 RCX: 00007fcb3e19aef9
RDX: 0000200000000200 RSI: 0000000000000720 RDI: 0000000000000004
RBP: 00007fcb3e22fee0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcb3e406038 R14: 00007fcb3e405fa0 R15: 00007fff757a4fc8
 </TASK>

The buggy address belongs to stack of task syz.4.22/6683
 and is located at offset 49 in frame:
 i2cdev_ioctl_smbus+0x0/0xac0 drivers/i2c/i2c-dev.c:632

This frame has 1 object:
 [48, 82) 'temp'

The buggy address belongs to a vmalloc virtual mapping
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7732f
memcg:ffff8880373cb702
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff ffff8880373cb702
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 5476, tgid 5476 (dhcpcd), ts 90580469351, free_ts 88678369553
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1e1/0x250 mm/page_alloc.c:1884
 prep_new_page mm/page_alloc.c:1892 [inline]
 get_page_from_freelist+0xe3d/0x2e10 mm/page_alloc.c:3945
 __alloc_frozen_pages_noprof+0x26c/0x2410 mm/page_alloc.c:5240
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486
 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline]
 alloc_pages_noprof+0x131/0x390 mm/mempolicy.c:2577
 vm_area_alloc_pages mm/vmalloc.c:3649 [inline]
 __vmalloc_area_node mm/vmalloc.c:3863 [inline]
 __vmalloc_node_range_noprof+0xe5c/0x1530 mm/vmalloc.c:4051
 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4111
 alloc_thread_stack_node kernel/fork.c:354 [inline]
 dup_task_struct kernel/fork.c:923 [inline]
 copy_process+0x5ec/0x7890 kernel/fork.c:2052
 kernel_clone+0xfc/0x930 kernel/fork.c:2651
 __do_sys_clone+0xd9/0x120 kernel/fork.c:2792
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 6054 tgid 6054 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0x822/0x1130 mm/page_alloc.c:2973
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 __do_kmalloc_node mm/slub.c:5656 [inline]
 __kmalloc_noprof+0x300/0x9c0 mm/slub.c:5669
 kmalloc_noprof include/linux/slab.h:961 [inline]
 tomoyo_realpath_from_path+0xb6/0x690 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x276/0x460 security/tomoyo/file.c:822
 security_inode_getattr+0x116/0x280 security/security.c:1869
 vfs_getattr fs/stat.c:259 [inline]
 vfs_fstat+0x4b/0xe0 fs/stat.c:281
 __do_sys_newfstat+0x8b/0x110 fs/stat.c:555
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffffc90003dffc80: f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90003dffd00: 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 f1 f1 00
>ffffc90003dffd80: 00 00 00 02 f3 f3 f3 f3 f3 00 00 00 00 00 00 00
                            ^
 ffffc90003dffe00: 00 00 00 00 00 f1 f1 f1 f1 f1 f1 04 f2 00 00 f3
 ffffc90003dffe80: f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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