================================================================== 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 ffff888035f401a5 by task syz.2.3865/25221 CPU: 1 UID: 0 PID: 25221 Comm: syz.2.3865 Tainted: G U 6.15.0-rc5-syzkaller-00032-g0d8d44db295c #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025 Call Trace: __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: 0033:0x7f060918e969 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:00007f0609f7e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007f06093b5fa0 RCX: 00007f060918e969 RDX: 0000000000000003 RSI: 0000200000000040 RDI: 0000000000000003 RBP: 00007f0609210ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f06093b5fa0 R15: 00007ffcfcc56868 Allocated by task 25221: 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 ffff888035f401a0 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 0 bytes to the right of allocated 5-byte region [ffff888035f401a0, ffff888035f401a5) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x35f40 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801b441500 ffffea000079ac40 dead000000000002 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 5822, tgid 5822 (syz-executor), ts 392746586452, free_ts 392746507667 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] __do_kmalloc_node mm/slub.c:4326 [inline] __kmalloc_node_noprof+0x2ed/0x500 mm/slub.c:4333 kmalloc_node_noprof include/linux/slab.h:932 [inline] __vmalloc_area_node mm/vmalloc.c:3647 [inline] __vmalloc_node_range_noprof+0x3eb/0x1540 mm/vmalloc.c:3844 __vmalloc_node_noprof mm/vmalloc.c:3907 [inline] vzalloc_noprof+0x6b/0x90 mm/vmalloc.c:3980 alloc_counters net/ipv6/netfilter/ip6_tables.c:815 [inline] copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:837 [inline] get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline] do_ip6t_get_ctl+0x63f/0xa50 net/ipv6/netfilter/ip6_tables.c:1677 nf_getsockopt+0x79/0xe0 net/netfilter/nf_sockopt.c:116 ipv6_getsockopt+0x1f7/0x280 net/ipv6/ipv6_sockglue.c:1493 tcp_getsockopt+0x9e/0x100 net/ipv4/tcp.c:4727 do_sock_getsockopt+0x3fc/0x800 net/socket.c:2357 __sys_getsockopt+0x123/0x1a0 net/socket.c:2386 page last free pid 5822 tgid 5822 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725 vfree+0x176/0x960 mm/vmalloc.c:3383 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:882 [inline] get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline] do_ip6t_get_ctl+0x869/0xa50 net/ipv6/netfilter/ip6_tables.c:1677 nf_getsockopt+0x79/0xe0 net/netfilter/nf_sockopt.c:116 ipv6_getsockopt+0x1f7/0x280 net/ipv6/ipv6_sockglue.c:1493 tcp_getsockopt+0x9e/0x100 net/ipv4/tcp.c:4727 do_sock_getsockopt+0x3fc/0x800 net/socket.c:2357 __sys_getsockopt+0x123/0x1a0 net/socket.c:2386 __do_sys_getsockopt net/socket.c:2393 [inline] __se_sys_getsockopt net/socket.c:2390 [inline] __x64_sys_getsockopt+0xbd/0x160 net/socket.c:2390 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 Memory state around the buggy address: ffff888035f40080: 05 fc fc fc 06 fc fc fc 05 fc fc fc 06 fc fc fc ffff888035f40100: fa fc fc fc 05 fc fc fc 05 fc fc fc 05 fc fc fc >ffff888035f40180: fa fc fc fc 05 fc fc fc fa fc fc fc 06 fc fc fc ^ ffff888035f40200: 00 fc fc fc 05 fc fc fc 05 fc fc fc fa fc fc fc ffff888035f40280: 05 fc fc fc 06 fc fc fc 00 fc fc fc 05 fc fc fc ==================================================================