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([2600:1700:6cf8:1240:57df:3a91:11ad:dcd]) by smtp.gmail.com with ESMTPSA id x125-20020a817c83000000b005a4da74b869sm225104ywc.139.2023.12.07.15.02.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 07 Dec 2023 15:02:06 -0800 (PST) Message-ID: <2133401f-2ba5-42eb-9158-dcc74db744f5@gmail.com> Date: Thu, 7 Dec 2023 15:02:05 -0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next] ipv6: add debug checks in fib6_info_release() Content-Language: en-US To: Eric Dumazet , "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: David Ahern , netdev@vger.kernel.org, eric.dumazet@gmail.com References: <20231205173250.2982846-1-edumazet@google.com> From: Kui-Feng Lee In-Reply-To: <20231205173250.2982846-1-edumazet@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Eric, could you also open a bug for this incident? On 12/5/23 09:32, Eric Dumazet wrote: > Some elusive syzbot reports are hinting to fib6_info_release(), > with a potential dangling f6i->gc_link anchor. > > Add debug checks so that syzbot can catch the issue earlier eventually. > > BUG: KASAN: slab-use-after-free in __hlist_del include/linux/list.h:990 [inline] > BUG: KASAN: slab-use-after-free in hlist_del_init include/linux/list.h:1016 [inline] > BUG: KASAN: slab-use-after-free in fib6_clean_expires_locked include/net/ip6_fib.h:533 [inline] > BUG: KASAN: slab-use-after-free in fib6_purge_rt+0x986/0x9c0 net/ipv6/ip6_fib.c:1064 > Write of size 8 at addr ffff88802805a840 by task syz-executor.1/10057 > > CPU: 1 PID: 10057 Comm: syz-executor.1 Not tainted 6.7.0-rc2-syzkaller-00029-g9b6de136b5f0 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 > Call Trace: > > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 > print_address_description mm/kasan/report.c:364 [inline] > print_report+0xc4/0x620 mm/kasan/report.c:475 > kasan_report+0xda/0x110 mm/kasan/report.c:588 > __hlist_del include/linux/list.h:990 [inline] > hlist_del_init include/linux/list.h:1016 [inline] > fib6_clean_expires_locked include/net/ip6_fib.h:533 [inline] > fib6_purge_rt+0x986/0x9c0 net/ipv6/ip6_fib.c:1064 > fib6_del_route net/ipv6/ip6_fib.c:1993 [inline] > fib6_del+0xa7a/0x1750 net/ipv6/ip6_fib.c:2038 > __ip6_del_rt net/ipv6/route.c:3866 [inline] > ip6_del_rt+0xf7/0x200 net/ipv6/route.c:3881 > ndisc_router_discovery+0x295b/0x3560 net/ipv6/ndisc.c:1372 > ndisc_rcv+0x3de/0x5f0 net/ipv6/ndisc.c:1856 > icmpv6_rcv+0x1470/0x19c0 net/ipv6/icmp.c:979 > ip6_protocol_deliver_rcu+0x170/0x13e0 net/ipv6/ip6_input.c:438 > ip6_input_finish+0x14f/0x2f0 net/ipv6/ip6_input.c:483 > NF_HOOK include/linux/netfilter.h:314 [inline] > NF_HOOK include/linux/netfilter.h:308 [inline] > ip6_input+0xa1/0xc0 net/ipv6/ip6_input.c:492 > ip6_mc_input+0x48b/0xf40 net/ipv6/ip6_input.c:586 > dst_input include/net/dst.h:461 [inline] > ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline] > NF_HOOK include/linux/netfilter.h:314 [inline] > NF_HOOK include/linux/netfilter.h:308 [inline] > ipv6_rcv+0x24e/0x380 net/ipv6/ip6_input.c:310 > __netif_receive_skb_one_core+0x115/0x180 net/core/dev.c:5529 > __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5643 > netif_receive_skb_internal net/core/dev.c:5729 [inline] > netif_receive_skb+0x133/0x700 net/core/dev.c:5788 > tun_rx_batched+0x429/0x780 drivers/net/tun.c:1579 > tun_get_user+0x29e3/0x3bc0 drivers/net/tun.c:2002 > tun_chr_write_iter+0xe8/0x210 drivers/net/tun.c:2048 > call_write_iter include/linux/fs.h:2020 [inline] > new_sync_write fs/read_write.c:491 [inline] > vfs_write+0x64f/0xdf0 fs/read_write.c:584 > ksys_write+0x12f/0x250 fs/read_write.c:637 > do_syscall_x64 arch/x86/entry/common.c:51 [inline] > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 > entry_SYSCALL_64_after_hwframe+0x63/0x6b > RIP: 0033:0x7f38e387b82f > Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 b9 80 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 0c 81 02 00 48 > RSP: 002b:00007f38e45c9090 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 > RAX: ffffffffffffffda RBX: 00007f38e399bf80 RCX: 00007f38e387b82f > RDX: 00000000000003b6 RSI: 0000000020000680 RDI: 00000000000000c8 > RBP: 00007f38e38c847a R08: 0000000000000000 R09: 0000000000000000 > R10: 00000000000003b6 R11: 0000000000000293 R12: 0000000000000000 > R13: 000000000000000b R14: 00007f38e399bf80 R15: 00007f38e3abfa48 > > > Allocated by task 10044: > kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 > kasan_set_track+0x25/0x30 mm/kasan/common.c:52 > ____kasan_kmalloc mm/kasan/common.c:374 [inline] > __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383 > kasan_kmalloc include/linux/kasan.h:198 [inline] > __do_kmalloc_node mm/slab_common.c:1007 [inline] > __kmalloc+0x59/0x90 mm/slab_common.c:1020 > kmalloc include/linux/slab.h:604 [inline] > kzalloc include/linux/slab.h:721 [inline] > fib6_info_alloc+0x40/0x160 net/ipv6/ip6_fib.c:155 > ip6_route_info_create+0x337/0x1e70 net/ipv6/route.c:3749 > ip6_route_add+0x26/0x150 net/ipv6/route.c:3843 > rt6_add_route_info+0x2e7/0x4b0 net/ipv6/route.c:4316 > rt6_route_rcv+0x76c/0xbf0 net/ipv6/route.c:985 > ndisc_router_discovery+0x138b/0x3560 net/ipv6/ndisc.c:1529 > ndisc_rcv+0x3de/0x5f0 net/ipv6/ndisc.c:1856 > icmpv6_rcv+0x1470/0x19c0 net/ipv6/icmp.c:979 > ip6_protocol_deliver_rcu+0x170/0x13e0 net/ipv6/ip6_input.c:438 > ip6_input_finish+0x14f/0x2f0 net/ipv6/ip6_input.c:483 > NF_HOOK include/linux/netfilter.h:314 [inline] > NF_HOOK include/linux/netfilter.h:308 [inline] > ip6_input+0xa1/0xc0 net/ipv6/ip6_input.c:492 > ip6_mc_input+0x48b/0xf40 net/ipv6/ip6_input.c:586 > dst_input include/net/dst.h:461 [inline] > ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline] > NF_HOOK include/linux/netfilter.h:314 [inline] > NF_HOOK include/linux/netfilter.h:308 [inline] > ipv6_rcv+0x24e/0x380 net/ipv6/ip6_input.c:310 > __netif_receive_skb_one_core+0x115/0x180 net/core/dev.c:5529 > __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5643 > netif_receive_skb_internal net/core/dev.c:5729 [inline] > netif_receive_skb+0x133/0x700 net/core/dev.c:5788 > tun_rx_batched+0x429/0x780 drivers/net/tun.c:1579 > tun_get_user+0x29e3/0x3bc0 drivers/net/tun.c:2002 > tun_chr_write_iter+0xe8/0x210 drivers/net/tun.c:2048 > call_write_iter include/linux/fs.h:2020 [inline] > new_sync_write fs/read_write.c:491 [inline] > vfs_write+0x64f/0xdf0 fs/read_write.c:584 > ksys_write+0x12f/0x250 fs/read_write.c:637 > do_syscall_x64 arch/x86/entry/common.c:51 [inline] > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 > entry_SYSCALL_64_after_hwframe+0x63/0x6b > > Freed by task 5123: > kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 > kasan_set_track+0x25/0x30 mm/kasan/common.c:52 > kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:522 > ____kasan_slab_free mm/kasan/common.c:236 [inline] > ____kasan_slab_free+0x15b/0x1b0 mm/kasan/common.c:200 > kasan_slab_free include/linux/kasan.h:164 [inline] > slab_free_hook mm/slub.c:1800 [inline] > slab_free_freelist_hook+0x114/0x1e0 mm/slub.c:1826 > slab_free mm/slub.c:3809 [inline] > __kmem_cache_free+0xc0/0x180 mm/slub.c:3822 > rcu_do_batch kernel/rcu/tree.c:2158 [inline] > rcu_core+0x819/0x1680 kernel/rcu/tree.c:2431 > __do_softirq+0x21a/0x8de kernel/softirq.c:553 > > Last potentially related work creation: > kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 > __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:492 > __call_rcu_common.constprop.0+0x9a/0x7a0 kernel/rcu/tree.c:2681 > fib6_info_release include/net/ip6_fib.h:332 [inline] > fib6_info_release include/net/ip6_fib.h:329 [inline] > rt6_route_rcv+0xa4e/0xbf0 net/ipv6/route.c:997 > ndisc_router_discovery+0x138b/0x3560 net/ipv6/ndisc.c:1529 > ndisc_rcv+0x3de/0x5f0 net/ipv6/ndisc.c:1856 > icmpv6_rcv+0x1470/0x19c0 net/ipv6/icmp.c:979 > ip6_protocol_deliver_rcu+0x170/0x13e0 net/ipv6/ip6_input.c:438 > ip6_input_finish+0x14f/0x2f0 net/ipv6/ip6_input.c:483 > NF_HOOK include/linux/netfilter.h:314 [inline] > NF_HOOK include/linux/netfilter.h:308 [inline] > ip6_input+0xa1/0xc0 net/ipv6/ip6_input.c:492 > ip6_mc_input+0x48b/0xf40 net/ipv6/ip6_input.c:586 > dst_input include/net/dst.h:461 [inline] > ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline] > NF_HOOK include/linux/netfilter.h:314 [inline] > NF_HOOK include/linux/netfilter.h:308 [inline] > ipv6_rcv+0x24e/0x380 net/ipv6/ip6_input.c:310 > __netif_receive_skb_one_core+0x115/0x180 net/core/dev.c:5529 > __netif_receive_skb+0x1f/0x1b0 net/core/dev.c:5643 > netif_receive_skb_internal net/core/dev.c:5729 [inline] > netif_receive_skb+0x133/0x700 net/core/dev.c:5788 > tun_rx_batched+0x429/0x780 drivers/net/tun.c:1579 > tun_get_user+0x29e3/0x3bc0 drivers/net/tun.c:2002 > tun_chr_write_iter+0xe8/0x210 drivers/net/tun.c:2048 > call_write_iter include/linux/fs.h:2020 [inline] > new_sync_write fs/read_write.c:491 [inline] > vfs_write+0x64f/0xdf0 fs/read_write.c:584 > ksys_write+0x12f/0x250 fs/read_write.c:637 > do_syscall_x64 arch/x86/entry/common.c:51 [inline] > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 > entry_SYSCALL_64_after_hwframe+0x63/0x6b > > Second to last potentially related work creation: > kasan_save_stack+0x33/0x50 mm/kasan/common.c:45 > __kasan_record_aux_stack+0xbc/0xd0 mm/kasan/generic.c:492 > insert_work+0x38/0x230 kernel/workqueue.c:1647 > __queue_work+0xcdc/0x11f0 kernel/workqueue.c:1803 > call_timer_fn+0x193/0x590 kernel/time/timer.c:1700 > expire_timers kernel/time/timer.c:1746 [inline] > __run_timers+0x585/0xb20 kernel/time/timer.c:2022 > run_timer_softirq+0x58/0xd0 kernel/time/timer.c:2035 > __do_softirq+0x21a/0x8de kernel/softirq.c:553 > > The buggy address belongs to the object at ffff88802805a800 > which belongs to the cache kmalloc-512 of size 512 > The buggy address is located 64 bytes inside of > freed 512-byte region [ffff88802805a800, ffff88802805aa00) > > The buggy address belongs to the physical page: > page:ffffea0000a01600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28058 > head:ffffea0000a01600 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0 > flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff) > page_type: 0xffffffff() > raw: 00fff00000000840 ffff888013041c80 ffffea0001e02600 dead000000000002 > raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > page_owner tracks the page as allocated > page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 18706, tgid 18699 (syz-executor.2), ts 999991973280, free_ts 996884464281 > set_page_owner include/linux/page_owner.h:31 [inline] > post_alloc_hook+0x2d0/0x350 mm/page_alloc.c:1537 > prep_new_page mm/page_alloc.c:1544 [inline] > get_page_from_freelist+0xa25/0x36d0 mm/page_alloc.c:3312 > __alloc_pages+0x22e/0x2420 mm/page_alloc.c:4568 > alloc_pages_mpol+0x258/0x5f0 mm/mempolicy.c:2133 > alloc_slab_page mm/slub.c:1870 [inline] > allocate_slab mm/slub.c:2017 [inline] > new_slab+0x283/0x3c0 mm/slub.c:2070 > ___slab_alloc+0x979/0x1500 mm/slub.c:3223 > __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3322 > __slab_alloc_node mm/slub.c:3375 [inline] > slab_alloc_node mm/slub.c:3468 [inline] > __kmem_cache_alloc_node+0x131/0x310 mm/slub.c:3517 > __do_kmalloc_node mm/slab_common.c:1006 [inline] > __kmalloc+0x49/0x90 mm/slab_common.c:1020 > kmalloc include/linux/slab.h:604 [inline] > kzalloc include/linux/slab.h:721 [inline] > copy_splice_read+0x1ac/0x8f0 fs/splice.c:338 > vfs_splice_read fs/splice.c:992 [inline] > vfs_splice_read+0x2ea/0x3b0 fs/splice.c:962 > splice_direct_to_actor+0x2a5/0xa30 fs/splice.c:1069 > do_splice_direct+0x1af/0x280 fs/splice.c:1194 > do_sendfile+0xb3e/0x1310 fs/read_write.c:1254 > __do_sys_sendfile64 fs/read_write.c:1322 [inline] > __se_sys_sendfile64 fs/read_write.c:1308 [inline] > __x64_sys_sendfile64+0x1d6/0x220 fs/read_write.c:1308 > do_syscall_x64 arch/x86/entry/common.c:51 [inline] > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82 > page last free stack trace: > reset_page_owner include/linux/page_owner.h:24 [inline] > free_pages_prepare mm/page_alloc.c:1137 [inline] > free_unref_page_prepare+0x4fa/0xaa0 mm/page_alloc.c:2347 > free_unref_page_list+0xe6/0xb40 mm/page_alloc.c:2533 > release_pages+0x32a/0x14f0 mm/swap.c:1042 > tlb_batch_pages_flush+0x9a/0x190 mm/mmu_gather.c:98 > tlb_flush_mmu_free mm/mmu_gather.c:293 [inline] > tlb_flush_mmu mm/mmu_gather.c:300 [inline] > tlb_finish_mmu+0x14b/0x6f0 mm/mmu_gather.c:392 > exit_mmap+0x38b/0xa70 mm/mmap.c:3321 > __mmput+0x12a/0x4d0 kernel/fork.c:1349 > mmput+0x62/0x70 kernel/fork.c:1371 > exit_mm kernel/exit.c:567 [inline] > do_exit+0x9ad/0x2ae0 kernel/exit.c:858 > do_group_exit+0xd4/0x2a0 kernel/exit.c:1021 > get_signal+0x23be/0x2790 kernel/signal.c:2904 > arch_do_signal_or_restart+0x90/0x7f0 arch/x86/kernel/signal.c:309 > exit_to_user_mode_loop kernel/entry/common.c:168 [inline] > exit_to_user_mode_prepare+0x121/0x240 kernel/entry/common.c:204 > irqentry_exit_to_user_mode+0xa/0x40 kernel/entry/common.c:309 > asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 > > Signed-off-by: Eric Dumazet > --- > include/net/ip6_fib.h | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h > index 1ba9f4ddf2f6db6c6ebf0a0675ca74fea2273fd9..e1e7a894863a7891610ce5afb2034473cc208d3e 100644 > --- a/include/net/ip6_fib.h > +++ b/include/net/ip6_fib.h > @@ -328,8 +328,11 @@ static inline bool fib6_info_hold_safe(struct fib6_info *f6i) > > static inline void fib6_info_release(struct fib6_info *f6i) > { > - if (f6i && refcount_dec_and_test(&f6i->fib6_ref)) > + if (f6i && refcount_dec_and_test(&f6i->fib6_ref)) { > + DEBUG_NET_WARN_ON_ONCE(fib6_has_expires(f6i)); > + DEBUG_NET_WARN_ON_ONCE(!hlist_unhashed(&f6i->gc_link)); > call_rcu(&f6i->rcu, fib6_info_destroy_rcu); > + } > } > > enum fib6_walk_state {