================================================================== 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 ffff8880279488e7 by task syz.0.58/6176 CPU: 1 UID: 0 PID: 6176 Comm: syz.0.58 Not tainted 6.15.0-rc5-syzkaller-00032-g0d8d44db295c #0 PREEMPT(full) 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: 0033:0x7fda0b98e969 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:00007fda0c805038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007fda0bbb5fa0 RCX: 00007fda0b98e969 RDX: 0000000000000003 RSI: 0000200000000080 RDI: 0000000000000006 RBP: 00007fda0ba10ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fda0bbb5fa0 R15: 00007fff930f61f8 Allocated by task 6176: 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 ffff8880279488e0 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 [ffff8880279488e0, ffff8880279488e7) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888027948fe0 pfn:0x27948 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000000 ffff88801b441500 ffffea000502bdc0 0000000000000002 raw: ffff888027948fe0 000000008080006b 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 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 12, tgid 12 (kworker/u8:0), ts 93798982106, free_ts 93659861902 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_noprof+0x2f2/0x510 mm/slub.c:4339 kmalloc_noprof include/linux/slab.h:909 [inline] kmalloc_array_noprof include/linux/slab.h:948 [inline] nsim_fib6_event_init drivers/net/netdevsim/fib.c:810 [inline] nsim_fib6_prepare_event drivers/net/netdevsim/fib.c:947 [inline] nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:1003 [inline] nsim_fib_event_nb+0x45e/0x10d0 drivers/net/netdevsim/fib.c:1043 notifier_call_chain+0xb9/0x410 kernel/notifier.c:85 atomic_notifier_call_chain+0x71/0x1c0 kernel/notifier.c:223 call_fib_notifiers+0x33/0x70 net/core/fib_notifier.c:35 call_fib6_entry_notifiers net/ipv6/ip6_fib.c:397 [inline] fib6_add_rt2node net/ipv6/ip6_fib.c:1231 [inline] fib6_add+0x25ef/0x4b60 net/ipv6/ip6_fib.c:1488 __ip6_ins_rt net/ipv6/route.c:1351 [inline] ip6_ins_rt+0xb5/0x110 net/ipv6/route.c:1361 __ipv6_ifa_notify+0xa6b/0xd60 net/ipv6/addrconf.c:6283 ipv6_ifa_notify net/ipv6/addrconf.c:6322 [inline] addrconf_dad_completed+0x19a/0x10d0 net/ipv6/addrconf.c:4321 page last free pid 5923 tgid 5917 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 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:4147 [inline] slab_alloc_node mm/slub.c:4196 [inline] kmem_cache_alloc_node_noprof+0x1d5/0x3b0 mm/slub.c:4248 __alloc_skb+0x2b2/0x380 net/core/skbuff.c:658 alloc_skb include/linux/skbuff.h:1340 [inline] __ip_append_data+0x3102/0x41e0 net/ipv4/ip_output.c:1125 ip_append_data net/ipv4/ip_output.c:1371 [inline] ip_append_data+0x10f/0x1a0 net/ipv4/ip_output.c:1350 raw_sendmsg+0xeed/0x38b0 net/ipv4/raw.c:651 inet_sendmsg+0x119/0x140 net/ipv4/af_inet.c:851 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0x973/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620 __sys_sendmmsg+0x200/0x420 net/socket.c:2709 __do_sys_sendmmsg net/socket.c:2736 [inline] __se_sys_sendmmsg net/socket.c:2733 [inline] __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2733 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: ffff888027948780: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc ffff888027948800: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc >ffff888027948880: fa fc fc fc fa fc fc fc fa fc fc fc 07 fc fc fc ^ ffff888027948900: 05 fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc ffff888027948980: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc ==================================================================