================================================================== BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:183 [inline] BUG: KASAN: use-after-free in atomic_read arch/x86/include/asm/atomic.h:27 [inline] BUG: KASAN: use-after-free in inet_twsk_purge+0x530/0x5a0 net/ipv4/inet_timewait_sock.c:276 Read of size 4 at addr ffff8880572f8084 by task kworker/u4:4/2850 CPU: 0 PID: 2850 Comm: kworker/u4:4 Not tainted 4.14.228-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351 kasan_report mm/kasan/report.c:409 [inline] __asan_report_load4_noabort+0x68/0x70 mm/kasan/report.c:429 __read_once_size include/linux/compiler.h:183 [inline] atomic_read arch/x86/include/asm/atomic.h:27 [inline] inet_twsk_purge+0x530/0x5a0 net/ipv4/inet_timewait_sock.c:276 ops_exit_list+0xf9/0x150 net/core/net_namespace.c:145 cleanup_net+0x3b3/0x840 net/core/net_namespace.c:484 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Allocated by task 8017: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551 kmem_cache_alloc+0x124/0x3c0 mm/slab.c:3552 kmem_cache_zalloc include/linux/slab.h:651 [inline] net_alloc net/core/net_namespace.c:362 [inline] copy_net_ns+0xf7/0x440 net/core/net_namespace.c:402 create_new_namespaces+0x375/0x720 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xa1/0x1d0 kernel/nsproxy.c:206 SYSC_unshare kernel/fork.c:2412 [inline] SyS_unshare+0x308/0x7f0 kernel/fork.c:2362 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb Freed by task 619: save_stack mm/kasan/kasan.c:447 [inline] set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3496 [inline] kmem_cache_free+0x7c/0x2b0 mm/slab.c:3758 net_free net/core/net_namespace.c:378 [inline] net_drop_ns+0x63/0x70 net/core/net_namespace.c:385 cleanup_net+0x526/0x840 net/core/net_namespace.c:502 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 The buggy address belongs to the object at ffff8880572f8080 which belongs to the cache net_namespace of size 8832 The buggy address is located 4 bytes inside of 8832-byte region [ffff8880572f8080, ffff8880572fa300) The buggy address belongs to the page: page:ffffea00015cbe00 count:1 mapcount:0 mapping:ffff8880572f8080 index:0x0 compound_mapcount: 0 flags: 0xfff00000008100(slab|head) raw: 00fff00000008100 ffff8880572f8080 0000000000000000 0000000100000001 raw: ffff8880b5583c48 ffffea00015ba120 ffff8880b5f92b40 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880572f7f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff8880572f8000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880572f8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880572f8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880572f8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================