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BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
BUG: KASAN: use-after-free in refcount_read include/linux/refcount.h:42 [inline]
BUG: KASAN: use-after-free in check_net include/net/net_namespace.h:236 [inline]
BUG: KASAN: use-after-free in rds_destroy_pending net/rds/rds.h:902 [inline]
BUG: KASAN: use-after-free in rds_cong_queue_updates+0x25d/0x5b0 net/rds/cong.c:226
Read of size 4 at addr ffff88019717c404 by task syz-executor0/18297

CPU: 0 PID: 18297 Comm: syz-executor0 Not tainted 4.18.0-rc3+ #127
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+0x1c9/0x2b4 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
 kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
 refcount_read include/linux/refcount.h:42 [inline]
 check_net include/net/net_namespace.h:236 [inline]
 rds_destroy_pending net/rds/rds.h:902 [inline]
 rds_cong_queue_updates+0x25d/0x5b0 net/rds/cong.c:226
 rds_recv_rcvbuf_delta.part.3+0x332/0x3e0 net/rds/recv.c:123
 rds_recv_rcvbuf_delta net/rds/recv.c:382 [inline]
 rds_recv_incoming+0x85a/0x1320 net/rds/recv.c:382
 rds_loop_xmit+0x16a/0x340 net/rds/loop.c:82
 rds_send_xmit+0x1343/0x29c0 net/rds/send.c:355
 rds_sendmsg+0x229e/0x2a40 net/rds/send.c:1243
 sock_sendmsg_nosec net/socket.c:641 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:651
 __sys_sendto+0x3d7/0x670 net/socket.c:1797
 __do_sys_sendto net/socket.c:1809 [inline]
 __se_sys_sendto net/socket.c:1805 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1805
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455ab9
Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007f3b4aeb2c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f3b4aeb36d4 RCX: 0000000000455ab9
RDX: 0000000000000481 RSI: 0000000020000000 RDI: 0000000000000013
RBP: 000000000072bf48 R08: 000000002069affb R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c0f1a R14: 00000000004d0e40 R15: 0000000000000001

Allocated by task 12258:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554
 kmem_cache_zalloc include/linux/slab.h:697 [inline]
 net_alloc net/core/net_namespace.c:383 [inline]
 copy_net_ns+0x15b/0x4d0 net/core/net_namespace.c:423
 create_new_namespaces+0x6ad/0x900 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xc3/0x1f0 kernel/nsproxy.c:206
 ksys_unshare+0x723/0xfb0 kernel/fork.c:2419
 __do_sys_unshare kernel/fork.c:2487 [inline]
 __se_sys_unshare kernel/fork.c:2485 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:2485
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6872:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x86/0x2d0 mm/slab.c:3756
 net_free net/core/net_namespace.c:399 [inline]
 net_drop_ns.part.14+0x129/0x150 net/core/net_namespace.c:406
 net_drop_ns net/core/net_namespace.c:405 [inline]
 cleanup_net+0x6bb/0xb50 net/core/net_namespace.c:541
 process_one_work+0xc73/0x1ba0 kernel/workqueue.c:2153
 worker_thread+0x189/0x13c0 kernel/workqueue.c:2296
 kthread+0x345/0x410 kernel/kthread.c:240
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412

The buggy address belongs to the object at ffff88019717c400
 which belongs to the cache net_namespace of size 8896
The buggy address is located 4 bytes inside of
 8896-byte region [ffff88019717c400, ffff88019717e6c0)
The buggy address belongs to the page:
page:ffffea00065c5f00 count:1 mapcount:0 mapping:ffff8801d9be9e40 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea000658ae08 ffffea0006448708 ffff8801d9be9e40
raw: 0000000000000000 ffff88019717c400 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88019717c300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88019717c380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88019717c400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88019717c480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88019717c500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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