================================================================== 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 ffff8880790b8647 by task syz.1.1197/11300 CPU: 0 UID: 0 PID: 11300 Comm: syz.1.1197 Tainted: G U 6.16.0-rc2-syzkaller-00162-g41687a5c6f8b #0 PREEMPT(full) Tainted: [U]=USER Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 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+0xcd/0x680 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+0x240/0x330 fs/proc/inode.c:342 do_loop_readv_writev fs/read_write.c:850 [inline] do_loop_readv_writev fs/read_write.c:835 [inline] vfs_writev+0x5dc/0xde0 fs/read_write.c:1059 do_writev+0x132/0x340 fs/read_write.c:1103 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fec9798e929 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:00007fec98801038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007fec97bb5fa0 RCX: 00007fec9798e929 RDX: 0000000000000003 RSI: 0000200000000080 RDI: 0000000000000005 RBP: 00007fec97a10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fec97bb5fa0 R15: 00007ffea18bdfa8 Allocated by task 11300: 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:4328 [inline] __kmalloc_node_track_caller_noprof+0x221/0x510 mm/slub.c:4347 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+0x240/0x330 fs/proc/inode.c:342 do_loop_readv_writev fs/read_write.c:850 [inline] do_loop_readv_writev fs/read_write.c:835 [inline] vfs_writev+0x5dc/0xde0 fs/read_write.c:1059 do_writev+0x132/0x340 fs/read_write.c:1103 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880790b8640 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 [ffff8880790b8640, ffff8880790b8647) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x790b8 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801b841500 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 5834, tgid 5834 (syz-executor), ts 237897324389, free_ts 237897312190 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1704 prep_new_page mm/page_alloc.c:1712 [inline] get_page_from_freelist+0x1321/0x3890 mm/page_alloc.c:3669 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:4959 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2419 alloc_slab_page mm/slub.c:2451 [inline] allocate_slab mm/slub.c:2619 [inline] new_slab+0x23b/0x330 mm/slub.c:2673 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3859 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3949 __slab_alloc_node mm/slub.c:4024 [inline] slab_alloc_node mm/slub.c:4185 [inline] __do_kmalloc_node mm/slub.c:4327 [inline] __kmalloc_node_noprof+0x2ed/0x500 mm/slub.c:4334 kmalloc_node_noprof include/linux/slab.h:932 [inline] __vmalloc_area_node mm/vmalloc.c:3690 [inline] __vmalloc_node_range_noprof+0x3e5/0x14b0 mm/vmalloc.c:3885 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:3948 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+0xa1/0x100 net/ipv4/tcp.c:4760 do_sock_getsockopt+0x3ff/0x800 net/socket.c:2357 __sys_getsockopt+0x123/0x1b0 net/socket.c:2386 page last free pid 5834 tgid 5834 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1248 [inline] __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706 __kasan_populate_vmalloc mm/kasan/shadow.c:383 [inline] kasan_populate_vmalloc+0x13d/0x1f0 mm/kasan/shadow.c:417 alloc_vmap_area+0x959/0x29c0 mm/vmalloc.c:2084 __get_vm_area_node+0x1ca/0x330 mm/vmalloc.c:3179 __vmalloc_node_range_noprof+0x271/0x14b0 mm/vmalloc.c:3845 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:3948 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+0xa1/0x100 net/ipv4/tcp.c:4760 do_sock_getsockopt+0x3ff/0x800 net/socket.c:2357 __sys_getsockopt+0x123/0x1b0 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/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff8880790b8500: fa fc fc fc 05 fc fc fc fa fc fc fc 06 fc fc fc ffff8880790b8580: fa fc fc fc 05 fc fc fc fa fc fc fc fa fc fc fc >ffff8880790b8600: 05 fc fc fc fa fc fc fc 07 fc fc fc 05 fc fc fc ^ ffff8880790b8680: fa fc fc fc fa fc fc fc fa fc fc fc 05 fc fc fc ffff8880790b8700: 05 fc fc fc fa fc fc fc 07 fc fc fc 05 fc fc fc 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