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BUG: KASAN: use-after-free in tcp_probe_timer net/ipv4/tcp_timer.c:372 [inline]
BUG: KASAN: use-after-free in tcp_write_timer_handler+0x8c6/0x8d0 net/ipv4/tcp_timer.c:615
Read of size 4 at addr ffff888062ff6714 by task syz-executor.0/9775

CPU: 1 PID: 9775 Comm: syz-executor.0 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506
 kasan_report+0x12/0x20 mm/kasan/common.c:641
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:134
 tcp_probe_timer net/ipv4/tcp_timer.c:372 [inline]
 tcp_write_timer_handler+0x8c6/0x8d0 net/ipv4/tcp_timer.c:615
 tcp_write_timer+0xac/0x2e0 net/ipv4/tcp_timer.c:631
 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:546 [inline]
 smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1146
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:update_stack_state+0x3ce/0x5f0 arch/x86/kernel/unwind_frame.c:213
Code: 16 00 00 00 00 48 8b 5d d0 65 48 33 1c 25 28 00 00 00 0f 85 fa 01 00 00 48 81 c4 a0 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <48> 8b 9d 68 ff ff ff 48 c7 85 60 ff ff ff 00 00 00 00 48 c7 85 70
RSP: 0018:ffffc900065ef6b8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffc900065efe40 RBX: 0000000000000000 RCX: 1ffff92000cbdf14
RDX: 1ffff92000cbdfbc RSI: ffffc900065efe40 RDI: ffffc900065ef8a0
RBP: ffffc900065ef780 R08: 0000000000000001 R09: ffffc900065ef8c0
R10: ffffc900065ef890 R11: ffffc900065ef8a0 R12: 1ffff92000cbdef7
R13: ffffc900065ef868 R14: 1ffff92000cbdedf R15: ffffc900065efe40
 unwind_next_frame.part.0+0x1a9/0xa20 arch/x86/kernel/unwind_frame.c:311
 unwind_next_frame+0x3b/0x50 arch/x86/kernel/unwind_frame.c:265
 arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8f/0xc0 kernel/stacktrace.c:123
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:515 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:529
 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 apparmor_sk_alloc_security+0x87/0x110 security/apparmor/lsm.c:776
 security_sk_alloc+0x77/0xc0 security/security.c:2101
 sk_prot_alloc+0xb8/0x310 net/core/sock.c:1606
 sk_alloc+0x39/0xfd0 net/core/sock.c:1657
 inet_create net/ipv4/af_inet.c:321 [inline]
 inet_create+0x363/0xe10 net/ipv4/af_inet.c:247
 __sock_create+0x3ce/0x730 net/socket.c:1433
 sock_create net/socket.c:1484 [inline]
 __sys_socket+0x103/0x220 net/socket.c:1526
 __do_sys_socket net/socket.c:1535 [inline]
 __se_sys_socket net/socket.c:1533 [inline]
 __x64_sys_socket+0x73/0xb0 net/socket.c:1533
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45ef97
Code: 00 00 00 49 89 ca b8 36 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 4a 8b fb ff c3 66 0f 1f 84 00 00 00 00 00 b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 2d 8b fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc08d40968 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 000000000071ccc0 RCX: 000000000045ef97
RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002
RBP: 0000000000000bc9 R08: 0000000000000408 R09: 0000000000004000
R10: 000000000071a4b0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc08d41130 R14: 0000000000000000 R15: 00007ffc08d41140

Allocated by task 9792:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:515 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:488
 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:523
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc mm/slab.c:3320 [inline]
 kmem_cache_alloc+0x121/0x710 mm/slab.c:3484
 kmem_cache_zalloc include/linux/slab.h:659 [inline]
 net_alloc net/core/net_namespace.c:403 [inline]
 copy_net_ns+0xf1/0x5a0 net/core/net_namespace.c:455
 create_new_namespaces+0x403/0xb50 kernel/nsproxy.c:108
 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:229
 ksys_unshare+0x444/0x980 kernel/fork.c:2955
 __do_sys_unshare kernel/fork.c:3023 [inline]
 __se_sys_unshare kernel/fork.c:3021 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3021
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 235:
 save_stack+0x23/0x90 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 kasan_set_free_info mm/kasan/common.c:337 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:476
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:485
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x86/0x320 mm/slab.c:3694
 net_free net/core/net_namespace.c:431 [inline]
 net_drop_ns.part.0+0xa6/0xe0 net/core/net_namespace.c:438
 net_drop_ns net/core/net_namespace.c:437 [inline]
 cleanup_net+0x803/0xb10 net/core/net_namespace.c:608
 process_one_work+0xa05/0x17a0 kernel/workqueue.c:2264
 worker_thread+0x98/0xe40 kernel/workqueue.c:2410
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff888062ff6140
 which belongs to the cache net_namespace of size 6912
The buggy address is located 1492 bytes inside of
 6912-byte region [ffff888062ff6140, ffff888062ff7c40)
The buggy address belongs to the page:
page:ffffea00018bfd80 refcount:1 mapcount:0 mapping:ffff88821bc53c40 index:0x0 compound_mapcount: 0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea0001981488 ffffea00017df388 ffff88821bc53c40
raw: 0000000000000000 ffff888062ff6140 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888062ff6600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888062ff6680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888062ff6700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888062ff6780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888062ff6800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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