================================================================== BUG: KASAN: use-after-free in tcp_probe_timer net/ipv4/tcp_timer.c:384 [inline] BUG: KASAN: use-after-free in tcp_write_timer_handler+0x882/0x9c0 net/ipv4/tcp_timer.c:648 Read of size 1 at addr ffff888073773b8d by task syz.0.4137/15429 CPU: 0 PID: 15429 Comm: syz.0.4137 Not tainted 5.15.162-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 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_probe_timer net/ipv4/tcp_timer.c:384 [inline] tcp_write_timer_handler+0x882/0x9c0 net/ipv4/tcp_timer.c:648 tcp_write_timer+0x12e/0x280 net/ipv4/tcp_timer.c:664 call_timer_fn+0x16d/0x560 kernel/time/timer.c:1451 expire_timers kernel/time/timer.c:1496 [inline] __run_timers+0x67c/0x890 kernel/time/timer.c:1767 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780 handle_softirqs+0x3a7/0x930 kernel/softirq.c:558 __do_softirq kernel/softirq.c:592 [inline] invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x157/0x240 kernel/softirq.c:641 irq_exit_rcu+0x5/0x20 kernel/softirq.c:653 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1096 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_acquire+0x252/0x4f0 kernel/locking/lockdep.c:5627 Code: 2b 00 74 08 4c 89 f7 e8 ac 7e 67 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc900031f7540 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff9200063eeb4 RCX: 1ffff9200063ee54 RDX: dffffc0000000000 RSI: ffffffff8a8b3ca0 RDI: ffffffff8ad8f680 RBP: ffffc900031f7698 R08: dffffc0000000000 R09: fffffbfff1f7f219 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff9200063eeb0 R13: dffffc0000000000 R14: ffffc900031f75a0 R15: 0000000000000246 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:739 [inline] workingset_activation+0x20/0x750 mm/workingset.c:403 mark_page_accessed+0xe0a/0x1330 mm/swap.c:426 zap_pte_range mm/memory.c:1370 [inline] zap_pmd_range mm/memory.c:1494 [inline] zap_pud_range mm/memory.c:1523 [inline] zap_p4d_range mm/memory.c:1544 [inline] unmap_page_range+0xe4f/0x2630 mm/memory.c:1565 unmap_vmas+0x1f8/0x390 mm/memory.c:1642 exit_mmap+0x3b6/0x670 mm/mmap.c:3186 __mmput+0x112/0x3b0 kernel/fork.c:1126 exit_mm+0x688/0x7f0 kernel/exit.c:548 do_exit+0x626/0x2480 kernel/exit.c:859 do_group_exit+0x144/0x310 kernel/exit.c:994 __do_sys_exit_group kernel/exit.c:1005 [inline] __se_sys_exit_group kernel/exit.c:1003 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1003 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f251987abd9 Code: Unable to access opcode bytes at RIP 0x7f251987abaf. RSP: 002b:00007ffdc8c16cb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f251987abd9 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000bc8c16ddf R09: 0000000000000000 R10: 00007f2518f02000 R11: 0000000000000246 R12: 00007ffdc8c16da0 R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffdc8c16da0 Allocated by task 3859: 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:408 [inline] copy_net_ns+0x140/0x5d0 net/core/net_namespace.c:463 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:3101 __do_sys_unshare kernel/fork.c:3175 [inline] __se_sys_unshare kernel/fork.c:3173 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3173 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff888073773500 which belongs to the cache net_namespace of size 6528 The buggy address is located 1677 bytes inside of 6528-byte region [ffff888073773500, ffff888073774e80) The buggy address belongs to the page: page:ffffea0001cddc00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888073773500 pfn:0x73770 head:ffffea0001cddc00 order:3 compound_mapcount:0 compound_pincount:0 memcg:ffff88801a6a7141 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 0000000100000001 ffff888011dec3c0 raw: ffff888073773500 0000000080040001 00000001ffffffff ffff88801a6a7141 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 3510, ts 40580644304, free_ts 40579545534 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:5423 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:408 [inline] copy_net_ns+0x140/0x5d0 net/core/net_namespace.c:463 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:3101 __do_sys_unshare kernel/fork.c:3175 [inline] __se_sys_unshare kernel/fork.c:3173 [inline] __x64_sys_unshare+0x34/0x40 kernel/fork.c:3173 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 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+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/0x1190 net/netlink/af_netlink.c:1999 ____sys_recvmsg+0x286/0x530 ___sys_recvmsg+0x1ec/0x690 net/socket.c:2692 __sys_recvmsg net/socket.c:2722 [inline] __do_sys_recvmsg net/socket.c:2732 [inline] __se_sys_recvmsg net/socket.c:2729 [inline] __x64_sys_recvmsg+0x1dc/0x2b0 net/socket.c:2729 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 Memory state around the buggy address: ffff888073773a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888073773b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888073773b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888073773c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888073773c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: 2b 00 sub (%rax),%eax 2: 74 08 je 0xc 4: 4c 89 f7 mov %r14,%rdi 7: e8 ac 7e 67 00 call 0x677eb8 c: f6 44 24 61 02 testb $0x2,0x61(%rsp) 11: 0f 85 84 01 00 00 jne 0x19b 17: 41 f7 c7 00 02 00 00 test $0x200,%r15d 1e: 74 01 je 0x21 20: fb sti 21: 48 c7 44 24 40 0e 36 movq $0x45e0360e,0x40(%rsp) 28: e0 45 * 2a: 4b c7 44 25 00 00 00 movq $0x0,0x0(%r13,%r12,1) <-- trapping instruction 31: 00 00 33: 43 c7 44 25 09 00 00 movl $0x0,0x9(%r13,%r12,1) 3a: 00 00 3c: 43 rex.XB 3d: c7 .byte 0xc7 3e: 44 rex.R 3f: 25 .byte 0x25