================================================================== BUG: KASAN: use-after-free in tcp_retransmit_timer+0x6ee/0x2890 net/ipv4/tcp_timer.c:515 Read of size 8 at addr ffff888020d50258 by task dhcpcd/3174 CPU: 0 PID: 3174 Comm: dhcpcd Not tainted 5.15.111-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 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:1096 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:85 [inline] RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline] RIP: 0010:kasan_check_range+0x77/0x290 mm/kasan/generic.c:189 Code: 03 49 bb 01 00 00 00 00 fc ff df 4f 8d 34 1a 4c 89 f5 4c 29 cd 48 83 fd 10 7f 26 48 85 ed 0f 84 3a 01 00 00 49 f7 d2 49 01 da <41> 80 39 00 0f 85 c4 01 00 00 49 ff c1 49 ff c2 75 ee e9 1d 01 00 RSP: 0018:ffffc900031bf858 EFLAGS: 00000286 RAX: 0000000000000001 RBX: 1ffff92000637f20 RCX: ffffffff81bef9ed RDX: 0000000000000001 RSI: 0000000000000028 RDI: ffffc900031bf900 RBP: 0000000000000005 R08: dffffc0000000000 R09: fffff52000637f21 R10: fffffffffffffffc R11: dffffc0000000001 R12: 0000000000012cc0 R13: 1ffff92000637f1c R14: fffff52000637f25 R15: 1ffff92000637f18 memset+0x1f/0x40 mm/kasan/shadow.c:44 __alloc_pages+0xbd/0x700 mm/page_alloc.c:5389 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 vm_area_alloc+0x20/0xe0 kernel/fork.c:349 mmap_region+0xad4/0x1670 mm/mmap.c:1771 do_mmap+0x78d/0xe00 mm/mmap.c:1575 vm_mmap_pgoff+0x1ca/0x2d0 mm/util.c:551 ksys_mmap_pgoff+0x13e/0x780 mm/mmap.c:1624 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 RIP: 0033:0x7f9e19f187e9 Code: 89 e0 5b 5d 41 5c c3 41 89 ca 41 f7 c1 ff 0f 00 00 74 10 48 8b 05 2f 36 0d 00 64 c7 00 16 00 00 00 eb 1b b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 10 48 8b 15 10 36 0d 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffebe261d98 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007ffebe2620b4 RCX: 00007f9e19f187e9 RDX: 0000000000000003 RSI: 0000000000009000 RDI: 0000000000000000 RBP: 00007ffebe262138 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000020022 R11: 0000000000000246 R12: 0000000000009000 R13: 00007ffebe262310 R14: 0000000000000002 R15: 00007ffebe262138 Allocated by task 3530: 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 ffff888020d50000 which belongs to the cache net_namespace of size 6464 The buggy address is located 600 bytes inside of 6464-byte region [ffff888020d50000, ffff888020d51940) The buggy address belongs to the page: page:ffffea0000835400 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888020d50000 pfn:0x20d50 head:ffffea0000835400 order:3 compound_mapcount:0 compound_pincount:0 memcg:ffff88801e4cbbc1 flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000010200 0000000000000000 0000000100000001 ffff888011dc63c0 raw: ffff888020d50000 0000000080040000 00000001ffffffff ffff88801e4cbbc1 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 3530, ts 89618345854, free_ts 89617354123 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/0x1190 net/netlink/af_netlink.c:2001 ____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: ffff888020d50100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888020d50180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888020d50200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888020d50280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888020d50300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 49 bb 01 00 00 00 00 movabs $0xdffffc0000000001,%r11 7: fc ff df a: 4f 8d 34 1a lea (%r10,%r11,1),%r14 e: 4c 89 f5 mov %r14,%rbp 11: 4c 29 cd sub %r9,%rbp 14: 48 83 fd 10 cmp $0x10,%rbp 18: 7f 26 jg 0x40 1a: 48 85 ed test %rbp,%rbp 1d: 0f 84 3a 01 00 00 je 0x15d 23: 49 f7 d2 not %r10 26: 49 01 da add %rbx,%r10 * 29: 41 80 39 00 cmpb $0x0,(%r9) <-- trapping instruction 2d: 0f 85 c4 01 00 00 jne 0x1f7 33: 49 ff c1 inc %r9 36: 49 ff c2 inc %r10 39: 75 ee jne 0x29 3b: e9 .byte 0xe9 3c: 1d .byte 0x1d 3d: 01 00 add %eax,(%rax)