==================================================================
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+0x1380/0x15d0 fs/afs/addr_prefs.c:415
Read of size 1 at addr ffff88801dab1f07 by task syz.2.1793/14961

CPU: 1 UID: 0 PID: 14961 Comm: syz.2.1793 Not tainted 6.14.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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+0xd9/0x110 mm/kasan/report.c:634
 afs_split_string fs/afs/addr_prefs.c:51 [inline]
 afs_proc_addr_prefs_write+0x1380/0x15d0 fs/afs/addr_prefs.c:415
 proc_simple_write+0x114/0x1b0 fs/proc/generic.c:817
 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:843 [inline]
 do_loop_readv_writev fs/read_write.c:828 [inline]
 vfs_writev+0x6da/0xdd0 fs/read_write.c:1052
 do_writev+0x133/0x340 fs/read_write.c:1096
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3a9e18d169
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:00007f3a9f044038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f3a9e3a5fa0 RCX: 00007f3a9e18d169
RDX: 0000000000000003 RSI: 0000400000000080 RDI: 0000000000000005
RBP: 00007f3a9e20e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3a9e3a5fa0 R15: 00007fff99793d48
 </TASK>

Allocated by task 14961:
 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:4294 [inline]
 __kmalloc_node_track_caller_noprof+0x222/0x510 mm/slub.c:4313
 memdup_user_nul+0x2b/0x110 mm/util.c:301
 proc_simple_write+0xc7/0x1b0 fs/proc/generic.c:814
 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:843 [inline]
 do_loop_readv_writev fs/read_write.c:828 [inline]
 vfs_writev+0x6da/0xdd0 fs/read_write.c:1052
 do_writev+0x133/0x340 fs/read_write.c:1096
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88801dab1f00
 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 [ffff88801dab1f00, ffff88801dab1f07)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1dab1
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b041500 dead000000000100 dead000000000122
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 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid 1 (swapper/0), ts 3449383443, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1551
 prep_new_page mm/page_alloc.c:1559 [inline]
 get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3477
 __alloc_frozen_pages_noprof+0x221/0x2470 mm/page_alloc.c:4740
 alloc_pages_mpol+0x1fc/0x540 mm/mempolicy.c:2270
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab mm/slub.c:2587 [inline]
 new_slab+0x23d/0x330 mm/slub.c:2640
 ___slab_alloc+0xc5d/0x1720 mm/slub.c:3826
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3916
 __slab_alloc_node mm/slub.c:3991 [inline]
 slab_alloc_node mm/slub.c:4152 [inline]
 __do_kmalloc_node mm/slub.c:4293 [inline]
 __kmalloc_node_track_caller_noprof+0x2f1/0x510 mm/slub.c:4313
 __kmemdup_nul mm/util.c:62 [inline]
 kstrdup+0x53/0x100 mm/util.c:82
 kstrdup_const+0x63/0x80 mm/util.c:102
 __kernfs_new_node+0x9c/0x890 fs/kernfs/dir.c:620
 kernfs_new_node+0x186/0x240 fs/kernfs/dir.c:700
 kernfs_create_link+0xcc/0x240 fs/kernfs/symlink.c:39
 sysfs_do_create_link_sd+0x90/0x140 fs/sysfs/symlink.c:44
 sysfs_do_create_link fs/sysfs/symlink.c:80 [inline]
 sysfs_create_link+0x61/0xc0 fs/sysfs/symlink.c:92
 device_add_class_symlinks drivers/base/core.c:3425 [inline]
 device_add+0x62e/0x1a70 drivers/base/core.c:3617
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88801dab1e00: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc
 ffff88801dab1e80: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc
>ffff88801dab1f00: 07 fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc
                   ^
 ffff88801dab1f80: fa fc fc fc fa fc fc fc 05 fc fc fc fa fc fc fc
 ffff88801dab2000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================