================================================================== 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 ffff88809f8e6610 by task syz-executor.0/4582 CPU: 1 PID: 4582 Comm: syz-executor.0 Not tainted 5.3.0-rc7+ #0 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:618 __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:1133 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:do_syscall_64+0x5b/0x6a0 arch/x86/entry/common.c:284 Code: ff df 48 c1 ea 03 80 3c 02 00 0f 85 99 05 00 00 48 83 3d 67 51 d2 07 00 0f 84 9f 04 00 00 e8 4c d2 71 00 fb 66 0f 1f 44 00 00 <65> 4c 8b 34 25 40 fe 01 00 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 RSP: 0018:ffff88809917ff20 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13 RAX: ffff8880a5eb8680 RBX: 0000000000000023 RCX: 1ffffffff134b5ce RDX: 0000000000000000 RSI: ffffffff8100a304 RDI: ffffffff8100a2d6 RBP: ffff88809917ff48 R08: ffff8880a5eb8680 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88809917ff58 R13: ffffffff88d2f460 R14: 0000000000000000 R15: 0000000000000000 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457d41 Code: 75 14 b8 23 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 24 d3 fb ff c3 48 83 ec 08 e8 ea 46 00 00 48 89 04 24 b8 23 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 33 47 00 00 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007ffe9c8b4140 EFLAGS: 00000293 ORIG_RAX: 0000000000000023 RAX: ffffffffffffffda RBX: 0000000000081f8a RCX: 0000000000457d41 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffe9c8b4150 RBP: 0000000000000001 R08: 00000000f195f5c1 R09: ffffffffffffffff R10: 00007ffe9c8b4240 R11: 0000000000000293 R12: 000000000075bf20 R13: 000000000075c9a0 R14: 0000000000760b38 R15: ffffffffffffffff Allocated by task 9885: save_stack+0x23/0x90 mm/kasan/common.c:69 set_track mm/kasan/common.c:77 [inline] __kasan_kmalloc mm/kasan/common.c:493 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:466 kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:501 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 7: 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:455 kasan_slab_free+0xe/0x10 mm/kasan/common.c:463 __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+0x774/0xa60 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 ffff88809f8e6040 which belongs to the cache net_namespace of size 6784 The buggy address is located 1488 bytes inside of 6784-byte region [ffff88809f8e6040, ffff88809f8e7ac0) The buggy address belongs to the page: page:ffffea00027e3980 refcount:1 mapcount:0 mapping:ffff88821b69e1c0 index:0x0 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffff8880a99d1348 ffffea00022b7808 ffff88821b69e1c0 raw: 0000000000000000 ffff88809f8e6040 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809f8e6500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809f8e6580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88809f8e6600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809f8e6680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88809f8e6700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================