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BUG: KASAN: slab-out-of-bounds in afs_split_string fs/afs/addr_prefs.c:51 [inline]
BUG: KASAN: slab-out-of-bounds in afs_proc_addr_prefs_write+0x13a9/0x15f0 fs/afs/addr_prefs.c:415
Read of size 1 at addr ffff888145b4afa7 by task syz.0.1103/10943

CPU: 0 UID: 0 PID: 10943 Comm: syz.0.1103 Not tainted 6.15.0-rc5-syzkaller-00136-g9c69f8884904 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 afs_split_string fs/afs/addr_prefs.c:51 [inline]
 afs_proc_addr_prefs_write+0x13a9/0x15f0 fs/afs/addr_prefs.c:415
 proc_simple_write+0x114/0x1b0 fs/proc/generic.c:825
 pde_write fs/proc/inode.c:330 [inline]
 proc_reg_write+0x23d/0x330 fs/proc/inode.c:342
 do_loop_readv_writev fs/read_write.c:848 [inline]
 do_loop_readv_writev fs/read_write.c:833 [inline]
 vfs_writev+0x6c4/0xdc0 fs/read_write.c:1057
 do_writev+0x132/0x330 fs/read_write.c:1101
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd0ce38e969
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:00007fd0cf13d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007fd0ce5b6080 RCX: 00007fd0ce38e969
RDX: 0000000000000003 RSI: 0000200000000080 RDI: 000000000000000c
RBP: 00007fd0ce410ab1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd0ce5b6080 R15: 00007ffe9844a588
 </TASK>

Allocated by task 10943:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_node_track_caller_noprof+0x221/0x510 mm/slub.c:4346
 memdup_user_nul+0x2b/0x120 mm/util.c:302
 proc_simple_write+0xc7/0x1b0 fs/proc/generic.c:822
 pde_write fs/proc/inode.c:330 [inline]
 proc_reg_write+0x23d/0x330 fs/proc/inode.c:342
 do_loop_readv_writev fs/read_write.c:848 [inline]
 do_loop_readv_writev fs/read_write.c:833 [inline]
 vfs_writev+0x6c4/0xdc0 fs/read_write.c:1057
 do_writev+0x132/0x330 fs/read_write.c:1101
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888145b4afa0
 which belongs to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes to the right of
 allocated 7-byte region [ffff888145b4afa0, ffff888145b4afa7)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x145b4a
anon flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000000 ffff88801b441500 0000000000000000 dead000000000001
raw: 0000000000000000 0000000080800080 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52c00(GFP_NOIO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid 1 (swapper/0), ts 21338923270, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 usb_control_msg+0xbc/0x4a0 drivers/usb/core/message.c:144
 set_port_feature drivers/usb/core/hub.c:464 [inline]
 hub_power_on+0x1c3/0x4e0 drivers/usb/core/hub.c:977
 hub_activate+0x13cb/0x1be0 drivers/usb/core/hub.c:1136
 hub_configure drivers/usb/core/hub.c:1743 [inline]
 hub_probe+0x213b/0x3340 drivers/usb/core/hub.c:1977
 usb_probe_interface+0x300/0x9c0 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:579 [inline]
 really_probe+0x23e/0xa90 drivers/base/dd.c:657
 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:799
 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:829
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888145b4ae80: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc
 ffff888145b4af00: fa fc fc fc 06 fc fc fc 06 fc fc fc fa fc fc fc
>ffff888145b4af80: fa fc fc fc 07 fc fc fc fa fc fc fc fa fc fc fc
                               ^
 ffff888145b4b000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888145b4b080: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc 00 00
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