Hello, syzbot found the following issue on: HEAD commit: a747e02430df ipv6: avoid possible NULL deref in modify_pre.. git tree: net console output: https://syzkaller.appspot.com/x/log.txt?x=10f77f78580000 kernel config: https://syzkaller.appspot.com/x/.config?x=3891b550f14aea0f dashboard link: https://syzkaller.appspot.com/bug?extid=55d58a05f0b5fd2ea0c7 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/34080a6fadb0/disk-a747e024.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/bc6aa3daa047/vmlinux-a747e024.xz kernel image: https://storage.googleapis.com/syzbot-assets/7defcc489e27/bzImage-a747e024.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+55d58a05f0b5fd2ea0c7@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: slab-use-after-free in sco_conn_free net/bluetooth/sco.c:87 [inline] BUG: KASAN: slab-use-after-free in kref_put include/linux/kref.h:65 [inline] BUG: KASAN: slab-use-after-free in sco_conn_put+0xad/0x210 net/bluetooth/sco.c:107 Write of size 8 at addr ffff8880226d05a0 by task syz-executor/5862 CPU: 0 UID: 0 PID: 5862 Comm: syz-executor Not tainted 6.12.0-syzkaller-10695-ga747e02430df #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x169/0x550 mm/kasan/report.c:489 kasan_report+0x143/0x180 mm/kasan/report.c:602 sco_conn_free net/bluetooth/sco.c:87 [inline] kref_put include/linux/kref.h:65 [inline] sco_conn_put+0xad/0x210 net/bluetooth/sco.c:107 hci_disconn_cfm include/net/bluetooth/hci_core.h:2050 [inline] hci_conn_hash_flush+0xff/0x240 net/bluetooth/hci_conn.c:2698 hci_dev_close_sync+0xa42/0x11c0 net/bluetooth/hci_sync.c:5212 hci_dev_do_close net/bluetooth/hci_core.c:483 [inline] hci_unregister_dev+0x20b/0x510 net/bluetooth/hci_core.c:2698 vhci_release+0x80/0xd0 drivers/bluetooth/hci_vhci.c:664 __fput+0x23c/0xa50 fs/file_table.c:450 task_work_run+0x24f/0x310 kernel/task_work.c:239 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0xa2f/0x28e0 kernel/exit.c:938 do_group_exit+0x207/0x2c0 kernel/exit.c:1087 __do_sys_exit_group kernel/exit.c:1098 [inline] __se_sys_exit_group kernel/exit.c:1096 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1096 x64_sys_call+0x26a8/0x26b0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8252380849 Code: Unable to access opcode bytes at 0x7f825238081f. RSP: 002b:00007fff0c285e98 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f8252380849 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043 RBP: 00007f82523dd978 R08: 00007fff0c283c37 R09: 000000000001abe9 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 000000000001abe9 R14: 0000000000000000 R15: 00007fff0c286720 </TASK> Allocated by task 7965: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x243/0x390 mm/slub.c:4314 kmalloc_noprof include/linux/slab.h:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] copy_verifier_state+0x944/0xec0 kernel/bpf/verifier.c:1514 is_state_visited kernel/bpf/verifier.c:18413 [inline] do_check+0x4522/0xfcd0 kernel/bpf/verifier.c:18575 do_check_common+0x1564/0x2010 kernel/bpf/verifier.c:21848 do_check_main kernel/bpf/verifier.c:21939 [inline] bpf_check+0x19380/0x1f1b0 kernel/bpf/verifier.c:22656 bpf_prog_load+0x1667/0x20f0 kernel/bpf/syscall.c:2947 __sys_bpf+0x4ee/0x810 kernel/bpf/syscall.c:5790 __do_sys_bpf kernel/bpf/syscall.c:5897 [inline] __se_sys_bpf kernel/bpf/syscall.c:5895 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5895 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 7965: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2338 [inline] slab_free mm/slub.c:4598 [inline] kfree+0x196/0x420 mm/slub.c:4746 free_func_state kernel/bpf/verifier.c:1452 [inline] free_verifier_state kernel/bpf/verifier.c:1461 [inline] free_states kernel/bpf/verifier.c:21729 [inline] do_check_common+0x19b2/0x2010 kernel/bpf/verifier.c:21860 do_check_main kernel/bpf/verifier.c:21939 [inline] bpf_check+0x19380/0x1f1b0 kernel/bpf/verifier.c:22656 bpf_prog_load+0x1667/0x20f0 kernel/bpf/syscall.c:2947 __sys_bpf+0x4ee/0x810 kernel/bpf/syscall.c:5790 __do_sys_bpf kernel/bpf/syscall.c:5897 [inline] __se_sys_bpf kernel/bpf/syscall.c:5895 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5895 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff8880226d0000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 1440 bytes inside of freed 2048-byte region [ffff8880226d0000, ffff8880226d0800) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x226d0 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801ac42000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000080008 00000001f5000000 0000000000000000 head: 00fff00000000040 ffff88801ac42000 dead000000000100 dead000000000122 head: 0000000000000000 0000000000080008 00000001f5000000 0000000000000000 head: 00fff00000000003 ffffea000089b401 ffffffffffffffff 0000000000000000 head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5855, tgid 5855 (syz-executor), ts 65737422958, free_ts 65730381330 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556 prep_new_page mm/page_alloc.c:1564 [inline] get_page_from_freelist+0x3649/0x3790 mm/page_alloc.c:3474 __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265 alloc_slab_page+0x6a/0x140 mm/slub.c:2408 allocate_slab+0x5a/0x2f0 mm/slub.c:2574 new_slab mm/slub.c:2627 [inline] ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3815 __slab_alloc+0x58/0xa0 mm/slub.c:3905 __slab_alloc_node mm/slub.c:3980 [inline] slab_alloc_node mm/slub.c:4141 [inline] __do_kmalloc_node mm/slub.c:4282 [inline] __kmalloc_node_track_caller_noprof+0x2e9/0x4c0 mm/slub.c:4302 kmalloc_reserve+0x111/0x2a0 net/core/skbuff.c:609 __alloc_skb+0x1f3/0x440 net/core/skbuff.c:678 alloc_skb include/linux/skbuff.h:1323 [inline] nlmsg_new include/net/netlink.h:1018 [inline] inet6_ifinfo_notify+0x72/0x120 net/ipv6/addrconf.c:6178 addrconf_notify+0xc6b/0x1020 net/ipv6/addrconf.c:3784 notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:85 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:9020 page last free pid 5848 tgid 5848 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1127 [inline] free_unref_page+0xdf9/0x1140 mm/page_alloc.c:2657 discard_slab mm/slub.c:2673 [inline] __put_partials+0xeb/0x130 mm/slub.c:3142 put_cpu_partial+0x17c/0x250 mm/slub.c:3217 __slab_free+0x2ea/0x3d0 mm/slub.c:4468 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4104 [inline] slab_alloc_node mm/slub.c:4153 [inline] __kmalloc_cache_noprof+0x1d9/0x390 mm/slub.c:4309 kmalloc_noprof include/linux/slab.h:901 [inline] kzalloc_noprof include/linux/slab.h:1037 [inline] ____ip_mc_inc_group+0x5a2/0xe50 net/ipv4/igmp.c:1468 __ip_mc_inc_group net/ipv4/igmp.c:1503 [inline] ip_mc_inc_group net/ipv4/igmp.c:1509 [inline] ip_mc_up+0x124/0x300 net/ipv4/igmp.c:1808 inetdev_event+0xfa4/0x1550 net/ipv4/devinet.c:1638 notifier_call_chain+0x19f/0x3e0 kernel/notifier.c:85 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:9020 do_setlink+0xc90/0x4210 net/core/rtnetlink.c:3109 rtnl_changelink net/core/rtnetlink.c:3723 [inline] __rtnl_newlink net/core/rtnetlink.c:3875 [inline] rtnl_newlink+0x171c/0x24f0 net/core/rtnetlink.c:4007 Memory state around the buggy address: ffff8880226d0480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880226d0500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880226d0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880226d0600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880226d0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
