================================================================== BUG: KASAN: use-after-free in skb_clear_hash include/linux/skbuff.h:1317 [inline] BUG: KASAN: use-after-free in tcf_ct_handle_fragments net/sched/act_ct.c:768 [inline] BUG: KASAN: use-after-free in tcf_ct_act+0x361f/0x3b40 net/sched/act_ct.c:1012 Write of size 4 at addr ffff88807d0ec454 by task syz.0.18/4318 CPU: 1 PID: 4318 Comm: syz.0.18 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106 print_address_description+0x60/0x2d0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0xdf/0x130 mm/kasan/report.c:451 skb_clear_hash include/linux/skbuff.h:1317 [inline] tcf_ct_handle_fragments net/sched/act_ct.c:768 [inline] tcf_ct_act+0x361f/0x3b40 net/sched/act_ct.c:1012 tcf_action_exec+0x177/0x570 net/sched/act_api.c:761 __tcf_classify net/sched/cls_api.c:1550 [inline] tcf_classify+0x218/0xad0 net/sched/cls_api.c:1616 sch_handle_ingress net/core/dev.c:5199 [inline] __netif_receive_skb_core+0x1cd8/0x3670 net/core/dev.c:5412 __netif_receive_skb_one_core net/core/dev.c:5549 [inline] __netif_receive_skb+0x74/0x290 net/core/dev.c:5665 netif_receive_skb_internal net/core/dev.c:5751 [inline] netif_receive_skb+0x19e/0x700 net/core/dev.c:5810 tun_rx_batched+0x606/0x760 drivers/net/tun.c:-1 tun_get_user+0x2bf4/0x3b10 drivers/net/tun.c:2000 tun_chr_write_iter+0x112/0x1e0 drivers/net/tun.c:2030 call_write_iter include/linux/fs.h:2179 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x748/0xd70 fs/read_write.c:594 ksys_write+0x153/0x260 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f02a7ad0159 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffeaf430408 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f02a7d57fa0 RCX: 00007f02a7ad0159 RDX: 0000000000000fce RSI: 0000200000001280 RDI: 0000000000000003 RBP: 00007f02a7b6706b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f02a7d57fac R14: 00007f02a7d57fa0 R15: 00007f02a7d57fa0 Allocated by task 4318: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x92/0xc0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3225 [inline] kmem_cache_alloc_node+0x184/0x2c0 mm/slub.c:3261 __alloc_skb+0xf4/0x750 net/core/skbuff.c:415 alloc_skb include/linux/skbuff.h:1162 [inline] alloc_skb_with_frags+0xa7/0x720 net/core/skbuff.c:6199 sock_alloc_send_pskb+0x87f/0x9a0 net/core/sock.c:2535 tun_alloc_skb drivers/net/tun.c:1515 [inline] tun_get_user+0x8f7/0x3b10 drivers/net/tun.c:1827 tun_chr_write_iter+0x112/0x1e0 drivers/net/tun.c:2030 call_write_iter include/linux/fs.h:2179 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x748/0xd70 fs/read_write.c:594 ksys_write+0x153/0x260 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Freed by task 4318: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1710 [inline] slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736 slab_free mm/slub.c:3504 [inline] kmem_cache_free+0x8f/0x210 mm/slub.c:3520 kfree_skb include/linux/skbuff.h:1118 [inline] nf_ct_frag6_queue net/ipv6/netfilter/nf_conntrack_reasm.c:261 [inline] nf_ct_frag6_gather+0x1002/0x1da0 net/ipv6/netfilter/nf_conntrack_reasm.c:486 tcf_ct_handle_fragments net/sched/act_ct.c:752 [inline] tcf_ct_act+0xc8d/0x3b40 net/sched/act_ct.c:1012 tcf_action_exec+0x177/0x570 net/sched/act_api.c:761 __tcf_classify net/sched/cls_api.c:1550 [inline] tcf_classify+0x218/0xad0 net/sched/cls_api.c:1616 sch_handle_ingress net/core/dev.c:5199 [inline] __netif_receive_skb_core+0x1cd8/0x3670 net/core/dev.c:5412 __netif_receive_skb_one_core net/core/dev.c:5549 [inline] __netif_receive_skb+0x74/0x290 net/core/dev.c:5665 netif_receive_skb_internal net/core/dev.c:5751 [inline] netif_receive_skb+0x19e/0x700 net/core/dev.c:5810 tun_rx_batched+0x606/0x760 drivers/net/tun.c:-1 tun_get_user+0x2bf4/0x3b10 drivers/net/tun.c:2000 tun_chr_write_iter+0x112/0x1e0 drivers/net/tun.c:2030 call_write_iter include/linux/fs.h:2179 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x748/0xd70 fs/read_write.c:594 ksys_write+0x153/0x260 fs/read_write.c:647 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff88807d0ec3c0 which belongs to the cache skbuff_head_cache of size 232 The buggy address is located 148 bytes inside of 232-byte region [ffff88807d0ec3c0, ffff88807d0ec4a8) The buggy address belongs to the page: page:ffffea0001f43b00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7d0ec flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 0000000000000000 0000000300000001 ffff88801bbe6140 raw: 0000000000000000 00000000800c000c 00000001ffffffff 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 0x12cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY), pid 3546, ts 15549732293, free_ts 15548596064 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501 alloc_slab_page mm/slub.c:1780 [inline] allocate_slab mm/slub.c:1917 [inline] new_slab+0xc0/0x4b0 mm/slub.c:1980 ___slab_alloc+0x807/0xdd0 mm/slub.c:3013 __slab_alloc mm/slub.c:3100 [inline] slab_alloc_node mm/slub.c:3191 [inline] kmem_cache_alloc_node+0x118/0x2c0 mm/slub.c:3261 __alloc_skb+0xf4/0x750 net/core/skbuff.c:415 alloc_skb include/linux/skbuff.h:1162 [inline] alloc_skb_with_frags+0xa7/0x720 net/core/skbuff.c:6199 sock_alloc_send_pskb+0x87f/0x9a0 net/core/sock.c:2535 unix_dgram_sendmsg+0x6f8/0x19c0 net/unix/af_unix.c:1809 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] __sys_sendto+0x46d/0x620 net/socket.c:2073 __do_sys_sendto net/socket.c:2085 [inline] __se_sys_sendto net/socket.c:2081 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2081 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1340 [inline] free_pcp_prepare mm/page_alloc.c:1391 [inline] free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317 free_unref_page+0x8f/0x2a0 mm/page_alloc.c:3396 sd_uninit_command+0x89/0x170 drivers/scsi/sd.c:1381 scsi_uninit_cmd drivers/scsi/scsi_lib.c:489 [inline] scsi_mq_uninit_cmd drivers/scsi/scsi_lib.c:507 [inline] scsi_end_request+0x3ac/0xa40 drivers/scsi/scsi_lib.c:570 scsi_io_completion+0x173/0x480 drivers/scsi/scsi_lib.c:940 blk_complete_reqs block/blk-mq.c:588 [inline] blk_done_softirq+0xfa/0x140 block/blk-mq.c:593 handle_softirqs+0x336/0x830 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 common_interrupt+0xb5/0xd0 arch/x86/kernel/irq.c:242 asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:667 unwind_get_return_address+0x27/0x80 arch/x86/kernel/unwind_orc.c:320 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:46 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360 Memory state around the buggy address: ffff88807d0ec300: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc ffff88807d0ec380: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb >ffff88807d0ec400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88807d0ec480: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc ffff88807d0ec500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================