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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+0x123b/0x14e0 fs/afs/addr_prefs.c:415
Read of size 1 at addr ffff88801fae0167 by task syz.3.4419/26371

CPU: 1 UID: 0 PID: 26371 Comm: syz.3.4419 Not tainted 6.13.0-rc3-syzkaller-00136-g8faabc041a00 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
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:378 [inline]
 print_report+0xc3/0x620 mm/kasan/report.c:489
 kasan_report+0xd9/0x110 mm/kasan/report.c:602
 afs_split_string fs/afs/addr_prefs.c:51 [inline]
 afs_proc_addr_prefs_write+0x123b/0x14e0 fs/afs/addr_prefs.c:415
 proc_simple_write+0x114/0x1b0 fs/proc/generic.c:815
 pde_write fs/proc/inode.c:330 [inline]
 proc_reg_write+0x23d/0x330 fs/proc/inode.c:342
 vfs_write+0x24c/0x1150 fs/read_write.c:677
 ksys_write+0x12b/0x250 fs/read_write.c:731
 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: 0033:0x7f0b99785d29
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:00007f0b9a58e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f0b99975fa0 RCX: 00007f0b99785d29
RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f0b99801aa8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f0b99975fa0 R15: 00007ffe0df1cfb8
 </TASK>

Allocated by task 26371:
 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:4298 [inline]
 __kmalloc_node_track_caller_noprof+0x21d/0x520 mm/slub.c:4317
 memdup_user_nul+0x2b/0x110 mm/util.c:305
 proc_simple_write+0xc7/0x1b0 fs/proc/generic.c:812
 pde_write fs/proc/inode.c:330 [inline]
 proc_reg_write+0x23d/0x330 fs/proc/inode.c:342
 vfs_write+0x24c/0x1150 fs/read_write.c:677
 ksys_write+0x12b/0x250 fs/read_write.c:731
 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 ffff88801fae0160
 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 [ffff88801fae0160, ffff88801fae0167)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1fae0
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801ac41500 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080800080 00000001f5000000 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 5922, tgid 5918 (syz.2.12), ts 76182236151, free_ts 76169050358
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1556
 prep_new_page mm/page_alloc.c:1564 [inline]
 get_page_from_freelist+0xfce/0x2f80 mm/page_alloc.c:3474
 __alloc_pages_noprof+0x223/0x25b0 mm/page_alloc.c:4751
 alloc_pages_mpol_noprof+0x2c9/0x610 mm/mempolicy.c:2269
 alloc_slab_page mm/slub.c:2423 [inline]
 allocate_slab mm/slub.c:2589 [inline]
 new_slab+0x2c9/0x410 mm/slub.c:2642
 ___slab_alloc+0xce2/0x1650 mm/slub.c:3830
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3920
 __slab_alloc_node mm/slub.c:3995 [inline]
 slab_alloc_node mm/slub.c:4156 [inline]
 __do_kmalloc_node mm/slub.c:4297 [inline]
 __kmalloc_node_track_caller_noprof+0x2ee/0x520 mm/slub.c:4317
 __kmemdup_nul mm/util.c:61 [inline]
 kstrdup+0x42/0xb0 mm/util.c:81
 kstrdup_const+0x63/0x80 mm/util.c:101
 __kernfs_new_node+0x9c/0x890 fs/kernfs/dir.c:620
 kernfs_new_node+0x186/0x240 fs/kernfs/dir.c:700
 kernfs_create_dir_ns+0x4c/0x150 fs/kernfs/dir.c:1061
 sysfs_create_dir_ns+0x13b/0x2b0 fs/sysfs/dir.c:59
 create_dir lib/kobject.c:73 [inline]
 kobject_add_internal+0x2c8/0x990 lib/kobject.c:240
 kobject_add_varg lib/kobject.c:374 [inline]
 kobject_add+0x16f/0x240 lib/kobject.c:426
page last free pid 11 tgid 11 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_page+0x661/0x1080 mm/page_alloc.c:2657
 __put_partials+0x14c/0x170 mm/slub.c:3157
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4119 [inline]
 slab_alloc_node mm/slub.c:4168 [inline]
 __kmalloc_cache_noprof+0x202/0x420 mm/slub.c:4324
 kmalloc_noprof include/linux/slab.h:901 [inline]
 kzalloc_noprof include/linux/slab.h:1037 [inline]
 ref_tracker_alloc+0x17c/0x5b0 lib/ref_tracker.c:203
 __netns_tracker_alloc include/net/net_namespace.h:341 [inline]
 netlink_release+0x17a6/0x2130 net/netlink/af_netlink.c:805
 __sock_release net/socket.c:640 [inline]
 sock_release+0x8e/0x1d0 net/socket.c:668
 netlink_kernel_release+0x4e/0x60 net/netlink/af_netlink.c:2075
 nfnetlink_net_exit_batch+0x101/0x360 net/netfilter/nfnetlink.c:790
 ops_exit_list+0x128/0x180 net/core/net_namespace.c:177
 cleanup_net+0x5b7/0xbd0 net/core/net_namespace.c:648
 process_one_work+0x958/0x1b30 kernel/workqueue.c:3229
 process_scheduled_works kernel/workqueue.c:3310 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
 kthread+0x2c1/0x3a0 kernel/kthread.c:389

Memory state around the buggy address:
 ffff88801fae0000: 05 fc fc fc fa fc fc fc 05 fc fc fc 05 fc fc fc
 ffff88801fae0080: 05 fc fc fc 05 fc fc fc 05 fc fc fc 00 fc fc fc
>ffff88801fae0100: 00 fc fc fc 02 fc fc fc fa fc fc fc 07 fc fc fc
                                                       ^
 ffff88801fae0180: fa fc fc fc 00 fc fc fc 05 fc fc fc 05 fc fc fc
 ffff88801fae0200: 07 fc fc fc 06 fc fc fc 05 fc fc fc 05 fc fc fc
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