================================================================== BUG: KASAN: use-after-free in tcp_retransmit_timer+0x6ee/0x2890 net/ipv4/tcp_timer.c:515 Read of size 8 at addr ffff8880440d9c98 by task kworker/u4:6/1450 CPU: 1 PID: 1450 Comm: kworker/u4:6 Not tainted 5.15.119-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 Workqueue: netns cleanup_net 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:1096 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_acquire+0xec/0x4f0 kernel/locking/lockdep.c:5595 Code: be 08 00 00 00 e8 84 ff 66 00 89 d8 48 0f a3 05 62 82 81 0c 73 0d e8 b3 66 08 00 84 c0 0f 84 b9 02 00 00 48 c7 c0 44 24 e4 8d <48> c1 e8 03 42 0f b6 04 28 84 c0 0f 85 dd 02 00 00 83 3d d0 b5 81 RSP: 0018:ffffc90005d078e0 EFLAGS: 00000202 RAX: ffffffff8de42444 RBX: 0000000000000001 RCX: ffffffff81626e3c RDX: 0000000000000000 RSI: ffffffff8ad86260 RDI: ffffffff8ad86220 RBP: ffffc90005d07a40 R08: dffffc0000000000 R09: fffffbfff1bc7e16 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000ba0f24 R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:269 rcu_read_lock include/linux/rcupdate.h:696 [inline] inet_twsk_purge+0x11e/0xa20 net/ipv4/inet_timewait_sock.c:268 ops_exit_list net/core/net_namespace.c:174 [inline] cleanup_net+0x763/0xb60 net/core/net_namespace.c:596 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2307 worker_thread+0xaca/0x1280 kernel/workqueue.c:2454 kthread+0x3f6/0x4f0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Allocated by task 8949: 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 ffff8880440d9a40 which belongs to the cache net_namespace of size 6464 The buggy address is located 600 bytes inside of 6464-byte region [ffff8880440d9a40, ffff8880440db380) The buggy address belongs to the page: page:ffffea0001103600 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880440dcec0 pfn:0x440d8 head:ffffea0001103600 order:3 compound_mapcount:0 compound_pincount:0 memcg:ffff8880771668c1 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 ffffea00011b6008 ffffea00011d0208 ffff888011dc63c0 raw: ffff8880440dcec0 0000000000040000 00000001ffffffff ffff8880771668c1 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 6738, ts 263723295527, free_ts 263708201124 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 copy_namespaces+0x365/0x3b0 kernel/nsproxy.c:178 copy_process+0x1841/0x3ef0 kernel/fork.c:2201 kernel_clone+0x210/0x960 kernel/fork.c:2601 __do_sys_clone kernel/fork.c:2718 [inline] __se_sys_clone kernel/fork.c:2702 [inline] __x64_sys_clone+0x23f/0x290 kernel/fork.c:2702 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_slab mm/slub.c:2015 [inline] discard_slab mm/slub.c:2021 [inline] __unfreeze_partials+0x1b7/0x210 mm/slub.c:2507 put_cpu_partial+0x132/0x1a0 mm/slub.c:2587 do_slab_free mm/slub.c:3487 [inline] ___cache_free+0xe3/0x100 mm/slub.c:3506 qlist_free_all+0x36/0x90 mm/kasan/quarantine.c:176 kasan_quarantine_reduce+0x162/0x180 mm/kasan/quarantine.c:283 __kasan_slab_alloc+0x2f/0xc0 mm/kasan/common.c:444 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 ptlock_alloc+0x1c/0x60 mm/memory.c:5510 ptlock_init include/linux/mm.h:2230 [inline] pgtable_pte_page_ctor include/linux/mm.h:2257 [inline] __pte_alloc_one include/asm-generic/pgalloc.h:66 [inline] pte_alloc_one+0xd1/0x360 arch/x86/mm/pgtable.c:33 __pte_alloc+0x75/0x210 mm/memory.c:439 copy_pte_range mm/memory.c:1021 [inline] copy_pmd_range mm/memory.c:1156 [inline] copy_pud_range mm/memory.c:1193 [inline] copy_p4d_range mm/memory.c:1217 [inline] copy_page_range+0x37cc/0x43b0 mm/memory.c:1290 dup_mmap kernel/fork.c:614 [inline] dup_mm+0xad6/0x1230 kernel/fork.c:1457 copy_mm+0x101/0x190 kernel/fork.c:1509 Memory state around the buggy address: ffff8880440d9b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880440d9c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880440d9c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880440d9d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880440d9d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: be 08 00 00 00 mov $0x8,%esi 5: e8 84 ff 66 00 callq 0x66ff8e a: 89 d8 mov %ebx,%eax c: 48 0f a3 05 62 82 81 bt %rax,0xc818262(%rip) # 0xc818276 13: 0c 14: 73 0d jae 0x23 16: e8 b3 66 08 00 callq 0x866ce 1b: 84 c0 test %al,%al 1d: 0f 84 b9 02 00 00 je 0x2dc 23: 48 c7 c0 44 24 e4 8d mov $0xffffffff8de42444,%rax * 2a: 48 c1 e8 03 shr $0x3,%rax <-- trapping instruction 2e: 42 0f b6 04 28 movzbl (%rax,%r13,1),%eax 33: 84 c0 test %al,%al 35: 0f 85 dd 02 00 00 jne 0x318 3b: 83 .byte 0x83 3c: 3d .byte 0x3d 3d: d0 .byte 0xd0 3e: b5 81 mov $0x81,%ch