================================================================== BUG: KASAN: use-after-free in tcp_retransmit_timer+0x6ee/0x2890 net/ipv4/tcp_timer.c:515 Read of size 8 at addr ffff8880205b8258 by task swapper/1/0 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.15.107-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 print_address_description+0x63/0x3b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:434 [inline] kasan_report+0x16b/0x1c0 mm/kasan/report.c:451 tcp_retransmit_timer+0x6ee/0x2890 net/ipv4/tcp_timer.c:515 tcp_write_timer_handler+0x1f7/0x9c0 net/ipv4/tcp_timer.c:626 tcp_write_timer+0x12e/0x280 net/ipv4/tcp_timer.c:646 call_timer_fn+0x16d/0x560 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1737 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1750 __do_softirq+0x3b3/0x93a kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x155/0x240 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:tick_nohz_idle_enter+0x22c/0x2f0 kernel/time/tick-sched.c:1116 Code: 00 4d 89 3c 24 42 0f b6 04 2b 84 c0 0f 85 a2 00 00 00 41 80 0e 04 e8 53 d8 e6 ff e8 4e 9a 13 00 fb 48 c7 44 24 20 0e 36 e0 45 <48> 8b 44 24 18 49 c7 44 05 00 00 00 00 00 65 48 8b 04 25 28 00 00 RSP: 0018:ffffc90000d67c80 EFLAGS: 00000282 RAX: 16d910d2223e6e00 RBX: 1ffff11017365582 RCX: ffffffff913aef03 RDX: dffffc0000000000 RSI: ffffffff8a8af0e0 RDI: ffffffff8ad85240 RBP: ffffc90000d67d30 R08: ffffffff81862a70 R09: ffffffff8f5ba048 R10: ffffffff8f5ba058 R11: ffffffff8f5ba050 R12: ffff8880b9b2ac40 R13: dffffc0000000000 R14: ffff8880b9b2ac14 R15: 00000047842cd8a2 do_idle+0xa7/0x670 kernel/sched/idle.c:280 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403 start_secondary+0x371/0x500 arch/x86/kernel/smpboot.c:270 secondary_startup_64_no_verify+0xb1/0xbb Allocated by task 3608: 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+0x8e/0xc0 mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook+0x53/0x380 mm/slab.h:519 slab_alloc_node mm/slub.c:3220 [inline] slab_alloc mm/slub.c:3228 [inline] kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233 kmem_cache_zalloc include/linux/slab.h:711 [inline] net_alloc net/core/net_namespace.c:405 [inline] copy_net_ns+0x143/0x5d0 net/core/net_namespace.c:460 create_new_namespaces+0x425/0x7a0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x11e/0x170 kernel/nsproxy.c:226 ksys_unshare+0x580/0xb20 kernel/fork.c:3094 __do_sys_unshare kernel/fork.c:3168 [inline] __se_sys_unshare kernel/fork.c:3166 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3166 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff8880205b8000 which belongs to the cache net_namespace of size 6464 The buggy address is located 600 bytes inside of 6464-byte region [ffff8880205b8000, ffff8880205b9940) The buggy address belongs to the page: page:ffffea0000816e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880205b8000 pfn:0x205b8 head:ffffea0000816e00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888011dc63c0 raw: ffff8880205b8000 0000000080040003 00000001ffffffff 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3608, ts 51079148664, free_ts 51077849518 prep_new_page mm/page_alloc.c:2426 [inline] get_page_from_freelist+0x322a/0x33c0 mm/page_alloc.c:4159 __alloc_pages+0x272/0x700 mm/page_alloc.c:5421 alloc_slab_page mm/slub.c:1775 [inline] allocate_slab mm/slub.c:1912 [inline] new_slab+0xbb/0x4b0 mm/slub.c:1975 ___slab_alloc+0x6f6/0xe10 mm/slub.c:3008 __slab_alloc mm/slub.c:3095 [inline] slab_alloc_node mm/slub.c:3186 [inline] slab_alloc mm/slub.c:3228 [inline] kmem_cache_alloc+0x18e/0x280 mm/slub.c:3233 kmem_cache_zalloc include/linux/slab.h:711 [inline] net_alloc net/core/net_namespace.c:405 [inline] copy_net_ns+0x143/0x5d0 net/core/net_namespace.c:460 create_new_namespaces+0x425/0x7a0 kernel/nsproxy.c:110 unshare_nsproxy_namespaces+0x11e/0x170 kernel/nsproxy.c:226 ksys_unshare+0x580/0xb20 kernel/fork.c:3094 __do_sys_unshare kernel/fork.c:3168 [inline] __se_sys_unshare kernel/fork.c:3166 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3166 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb 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+0xc34/0xcf0 mm/page_alloc.c:3317 free_unref_page+0x95/0x2d0 mm/page_alloc.c:3396 free_nonslab_page+0xe4/0x150 mm/slub.c:3535 kfree+0x1cf/0x270 mm/slub.c:4556 skb_free_head net/core/skbuff.c:655 [inline] skb_release_data+0x73a/0x8a0 net/core/skbuff.c:677 skb_release_all net/core/skbuff.c:742 [inline] __kfree_skb net/core/skbuff.c:756 [inline] consume_skb+0xa3/0x140 net/core/skbuff.c:914 skb_free_datagram+0x24/0xe0 net/core/datagram.c:325 netlink_recvmsg+0x5ef/0x1140 net/netlink/af_netlink.c:2030 ____sys_recvmsg+0x286/0x530 ___sys_recvmsg+0x1ec/0x690 net/socket.c:2673 __sys_recvmsg net/socket.c:2703 [inline] __do_sys_recvmsg net/socket.c:2713 [inline] __se_sys_recvmsg net/socket.c:2710 [inline] __x64_sys_recvmsg+0x1dc/0x2b0 net/socket.c:2710 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x61/0xcb Memory state around the buggy address: ffff8880205b8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880205b8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880205b8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880205b8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880205b8300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: 00 4d 89 add %cl,-0x77(%rbp) 3: 3c 24 cmp $0x24,%al 5: 42 0f b6 04 2b movzbl (%rbx,%r13,1),%eax a: 84 c0 test %al,%al c: 0f 85 a2 00 00 00 jne 0xb4 12: 41 80 0e 04 orb $0x4,(%r14) 16: e8 53 d8 e6 ff callq 0xffe6d86e 1b: e8 4e 9a 13 00 callq 0x139a6e 20: fb sti 21: 48 c7 44 24 20 0e 36 movq $0x45e0360e,0x20(%rsp) 28: e0 45 * 2a: 48 8b 44 24 18 mov 0x18(%rsp),%rax <-- trapping instruction 2f: 49 c7 44 05 00 00 00 movq $0x0,0x0(%r13,%rax,1) 36: 00 00 38: 65 gs 39: 48 rex.W 3a: 8b .byte 0x8b 3b: 04 25 add $0x25,%al 3d: 28 00 sub %al,(%rax)