==================================================================
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:897 [inline]
BUG: KASAN: use-after-free in rds_cong_queue_updates+0x255/0x590 net/rds/cong.c:226
Read of size 4 at addr ffff88018cbb02c4 by task syz-executor7/11105

CPU: 0 PID: 11105 Comm: syz-executor7 Not tainted 4.17.0+ #84
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+0x1b9/0x294 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:897 [inline]
 rds_cong_queue_updates+0x255/0x590 net/rds/cong.c:226
 rds_recv_rcvbuf_delta.part.3+0x2b9/0x350 net/rds/recv.c:118
 rds_recv_rcvbuf_delta net/rds/recv.c:377 [inline]
 rds_recv_incoming+0x83f/0x1300 net/rds/recv.c:377
 rds_loop_xmit+0x16a/0x340 net/rds/loop.c:82
 rds_send_xmit+0x131b/0x2990 net/rds/send.c:355
 rds_sendmsg+0x228d/0x2a30 net/rds/send.c:1243
 sock_sendmsg_nosec net/socket.c:645 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:655
 __sys_sendto+0x3d7/0x670 net/socket.c:1833
 __do_sys_sendto net/socket.c:1845 [inline]
 __se_sys_sendto net/socket.c:1841 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1841
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455b29
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:00007f0450b7cc68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f0450b7d6d4 RCX: 0000000000455b29
RDX: 0000000000000481 RSI: 0000000020000000 RDI: 0000000000000014
RBP: 000000000072bea0 R08: 000000002069affb R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c0f7f R14: 00000000004d0e70 R15: 0000000000000000

Allocated by task 6651:
 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
 getname_flags+0xd0/0x5a0 fs/namei.c:140
 user_path_at_empty+0x2d/0x50 fs/namei.c:2555
 do_readlinkat+0x143/0x3e0 fs/stat.c:394
 __do_sys_readlink fs/stat.c:427 [inline]
 __se_sys_readlink fs/stat.c:424 [inline]
 __x64_sys_readlink+0x78/0xb0 fs/stat.c:424
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6651:
 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
 putname+0xf2/0x130 fs/namei.c:261
 filename_lookup+0x38b/0x4f0 fs/namei.c:2330
 user_path_at_empty+0x40/0x50 fs/namei.c:2555
 do_readlinkat+0x143/0x3e0 fs/stat.c:394
 __do_sys_readlink fs/stat.c:427 [inline]
 __se_sys_readlink fs/stat.c:424 [inline]
 __x64_sys_readlink+0x78/0xb0 fs/stat.c:424
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88018cbb0d80
 which belongs to the cache names_cache of size 4096
The buggy address is located 2748 bytes to the left of
 4096-byte region [ffff88018cbb0d80, ffff88018cbb1d80)
The buggy address belongs to the page:
page:ffffea000632ec00 count:1 mapcount:0 mapping:ffff8801da986dc0 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea0006b7cf88 ffffea000632ec88 ffff8801da986dc0
raw: 0000000000000000 ffff88018cbb0d80 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88018cbb0180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88018cbb0200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88018cbb0280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                           ^
 ffff88018cbb0300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88018cbb0380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================