================================================================== BUG: KASAN: use-after-free in tcp_probe_timer net/ipv4/tcp_timer.c:360 [inline] BUG: KASAN: use-after-free in tcp_write_timer_handler+0x8c6/0x8d0 net/ipv4/tcp_timer.c:596 Read of size 4 at addr ffff88808e7fa710 by task syz-executor.5/2737 CPU: 0 PID: 2737 Comm: syz-executor.5 Not tainted 5.2.0+ #97 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482 kasan_report+0x12/0x17 mm/kasan/common.c:612 __asan_report_load4_noabort+0x14/0x20 mm/kasan/generic_report.c:131 tcp_probe_timer net/ipv4/tcp_timer.c:360 [inline] tcp_write_timer_handler+0x8c6/0x8d0 net/ipv4/tcp_timer.c:596 tcp_write_timer+0xa8/0x1e0 net/ipv4/tcp_timer.c:612 call_timer_fn+0x1ac/0x780 kernel/time/timer.c:1322 expire_timers kernel/time/timer.c:1366 [inline] __run_timers kernel/time/timer.c:1685 [inline] __run_timers kernel/time/timer.c:1653 [inline] run_timer_softirq+0x697/0x17a0 kernel/time/timer.c:1698 __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:537 [inline] smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1095 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:828 RIP: 0010:arch_atomic_add_negative arch/x86/include/asm/atomic.h:154 [inline] RIP: 0010:atomic_add_negative include/asm-generic/atomic-instrumented.h:768 [inline] RIP: 0010:page_remove_file_rmap mm/rmap.c:1238 [inline] RIP: 0010:page_remove_rmap+0x634/0x1190 mm/rmap.c:1303 Code: d0 ff 4c 89 e7 e8 2c 43 10 00 e9 c8 fa ff ff e8 32 9f d0 ff 49 8d 7c 24 30 be 04 00 00 00 e8 13 86 0a 00 f0 41 83 44 24 30 ff <0f> 98 c3 31 ff 89 de e8 50 a0 d0 ff 84 db 74 c3 41 bf ff ff ff ff RSP: 0018:ffff88808c2376e0 EFLAGS: 00000213 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81a1e5bd RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffea00009005f0 RBP: ffff88808c237720 R08: 1ffffd40001200be R09: fffff940001200bf R10: fffff940001200be R11: ffffea00009005f3 R12: ffffea00009005c0 R13: 0000000000000000 R14: ffffea00009005c8 R15: dead000000000100 zap_pte_range mm/memory.c:1059 [inline] zap_pmd_range mm/memory.c:1161 [inline] zap_pud_range mm/memory.c:1190 [inline] zap_p4d_range mm/memory.c:1211 [inline] unmap_page_range+0xd45/0x2170 mm/memory.c:1232 unmap_single_vma+0x19d/0x300 mm/memory.c:1277 unmap_vmas+0x135/0x280 mm/memory.c:1309 exit_mmap+0x2ba/0x530 mm/mmap.c:3145 __mmput kernel/fork.c:1064 [inline] mmput+0x179/0x4d0 kernel/fork.c:1085 exit_mm kernel/exit.c:547 [inline] do_exit+0x84e/0x2ea0 kernel/exit.c:864 do_group_exit+0x135/0x360 kernel/exit.c:981 get_signal+0x47c/0x2500 kernel/signal.c:2728 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:159 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459829 Code: Bad RIP value. RSP: 002b:00007ff68309fcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000075bfd0 RCX: 0000000000459829 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bfd0 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bfd4 R13: 00007fffb9f80adf R14: 00007ff6830a09c0 R15: 000000000075bfd4 Allocated by task 4837: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:487 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:460 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:495 slab_post_alloc_hook mm/slab.h:520 [inline] slab_alloc mm/slab.c:3319 [inline] kmem_cache_alloc+0x121/0x710 mm/slab.c:3483 kmem_cache_zalloc include/linux/slab.h:738 [inline] net_alloc net/core/net_namespace.c:410 [inline] copy_net_ns+0xf1/0x41f net/core/net_namespace.c:462 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:103 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:202 ksys_unshare+0x444/0x980 kernel/fork.c:2831 __do_sys_unshare kernel/fork.c:2899 [inline] __se_sys_unshare kernel/fork.c:2897 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2897 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 842: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:449 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457 __cache_free mm/slab.c:3425 [inline] kmem_cache_free+0x86/0x320 mm/slab.c:3693 net_free net/core/net_namespace.c:438 [inline] net_drop_ns.part.0+0x70/0x90 net/core/net_namespace.c:445 net_drop_ns net/core/net_namespace.c:444 [inline] cleanup_net+0x77a/0xa70 net/core/net_namespace.c:613 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269 worker_thread+0x98/0xe40 kernel/workqueue.c:2415 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 ffff88808e7fa140 which belongs to the cache net_namespace of size 6784 The buggy address is located 1488 bytes inside of 6784-byte region [ffff88808e7fa140, ffff88808e7fbbc0) The buggy address belongs to the page: page:ffffea000239fe80 refcount:1 mapcount:0 mapping:ffff8880a99dfe00 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea0001818508 ffffea0001af3808 ffff8880a99dfe00 raw: 0000000000000000 ffff88808e7fa140 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88808e7fa600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808e7fa680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88808e7fa700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88808e7fa780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88808e7fa800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================