================================================================== BUG: KASAN: global-out-of-bounds in fib6_ifdown+0x7f5/0x8f0 net/ipv6/route.c:4901 Read of size 8 at addr ffffffff9af80c50 by task syz.5.2410/19889 CPU: 3 UID: 0 PID: 19889 Comm: syz.5.2410 Not tainted 6.15.0-rc5-syzkaller-00353-gcd802e7e5f1e #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 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 fib6_ifdown+0x7f5/0x8f0 net/ipv6/route.c:4901 fib6_clean_node+0x2a4/0x5b0 net/ipv6/ip6_fib.c:2199 fib6_walk_continue+0x44f/0x8d0 net/ipv6/ip6_fib.c:2124 fib6_walk+0x182/0x370 net/ipv6/ip6_fib.c:2172 fib6_clean_tree+0xd4/0x110 net/ipv6/ip6_fib.c:2252 __fib6_clean_all+0x107/0x2d0 net/ipv6/ip6_fib.c:2268 rt6_sync_down_dev net/ipv6/route.c:4951 [inline] rt6_disable_ip+0x2ec/0x990 net/ipv6/route.c:4956 addrconf_ifdown.isra.0+0x11d/0x1a90 net/ipv6/addrconf.c:3857 addrconf_notify+0x220/0x19e0 net/ipv6/addrconf.c:3780 notifier_call_chain+0xb9/0x410 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2176 call_netdevice_notifiers_extack net/core/dev.c:2214 [inline] call_netdevice_notifiers net/core/dev.c:2228 [inline] unregister_netdevice_many_notify+0xf9a/0x26f0 net/core/dev.c:11970 unregister_netdevice_many net/core/dev.c:12034 [inline] unregister_netdevice_queue+0x305/0x3f0 net/core/dev.c:11877 unregister_netdevice include/linux/netdevice.h:3374 [inline] __tun_detach+0x1249/0x1540 drivers/net/tun.c:620 tun_detach drivers/net/tun.c:636 [inline] tun_chr_close+0xc2/0x230 drivers/net/tun.c:3390 __fput+0x3ff/0xb70 fs/file_table.c:465 task_work_run+0x14d/0x240 kernel/task_work.c:227 get_signal+0x1d1/0x26d0 kernel/signal.c:2807 arch_do_signal_or_restart+0x8f/0x7a0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 __do_fast_syscall_32+0x80/0x120 arch/x86/entry/syscall_32.c:309 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf705e579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f500c55c EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: fffffffffffffff2 RBX: 0000000000000008 RCX: 00000000400454ca RDX: 00000000800000c0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 The buggy address belongs to the variable: __key.0+0x30/0x40 The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1af80 flags: 0xfff00000002000(reserved|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000002000 ffffea00006be008 ffffea00006be008 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner info is not present (never set?) Memory state around the buggy address: ffffffff9af80b00: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 ffffffff9af80b80: f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 >ffffffff9af80c00: f9 f9 f9 f9 00 00 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 ^ ffffffff9af80c80: f9 f9 f9 f9 00 00 00 00 00 00 00 00 00 00 00 00 ffffffff9af80d00: 00 00 00 f9 f9 f9 f9 f9 00 00 f9 f9 f9 f9 f9 f9 ================================================================== ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi