==================================================================
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:43 [inline]
BUG: KASAN: use-after-free in check_net include/net/net_namespace.h:254 [inline]
BUG: KASAN: use-after-free in rds_destroy_pending net/rds/rds.h:951 [inline]
BUG: KASAN: use-after-free in rds_cong_queue_updates+0x209/0x4d0 net/rds/cong.c:229
Read of size 4 at addr ffff88808ae94304 by task kworker/u4:8/10449

CPU: 1 PID: 10449 Comm: kworker/u4:8 Not tainted 5.0.0+ #7
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: krdsd rds_send_worker
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x123/0x190 mm/kasan/generic.c:191
 kasan_check_read+0x11/0x20 mm/kasan/common.c:100
 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
 refcount_read include/linux/refcount.h:43 [inline]
 check_net include/net/net_namespace.h:254 [inline]
 rds_destroy_pending net/rds/rds.h:951 [inline]
 rds_cong_queue_updates+0x209/0x4d0 net/rds/cong.c:229
 rds_recv_rcvbuf_delta.part.0+0x34f/0x3f0 net/rds/recv.c:118
 rds_recv_rcvbuf_delta net/rds/recv.c:379 [inline]
 rds_recv_incoming+0x789/0x11f0 net/rds/recv.c:379
 rds_loop_xmit+0xf3/0x2a0 net/rds/loop.c:96
 rds_send_xmit+0x1113/0x2560 net/rds/send.c:355
 rds_send_worker+0x90/0x290 net/rds/threads.c:200
 process_one_work+0x98e/0x1790 kernel/workqueue.c:2173
 worker_thread+0x98/0xe40 kernel/workqueue.c:2319
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352

Allocated by task 17749:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc mm/kasan/common.c:495 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:468
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:509
 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3615
 kmalloc include/linux/slab.h:545 [inline]
 kzalloc include/linux/slab.h:740 [inline]
 kernfs_iop_get_link fs/kernfs/symlink.c:136 [inline]
 kernfs_iop_get_link+0x6a/0x680 fs/kernfs/symlink.c:127
 vfs_readlink+0x1f7/0x3e0 fs/namei.c:4735
 do_readlinkat+0x2ab/0x320 fs/stat.c:409
 __do_sys_readlink fs/stat.c:430 [inline]
 __se_sys_readlink fs/stat.c:427 [inline]
 __x64_sys_readlink+0x78/0xb0 fs/stat.c:427
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 17749:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:457
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:465
 __cache_free mm/slab.c:3494 [inline]
 kfree+0xcf/0x230 mm/slab.c:3811
 kfree_link+0x16/0x20 fs/libfs.c:1105
 do_delayed_call include/linux/delayed_call.h:28 [inline]
 vfs_readlink+0x160/0x3e0 fs/namei.c:4740
 do_readlinkat+0x2ab/0x320 fs/stat.c:409
 __do_sys_readlink fs/stat.c:430 [inline]
 __se_sys_readlink fs/stat.c:427 [inline]
 __x64_sys_readlink+0x78/0xb0 fs/stat.c:427
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88808ae94200
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 260 bytes inside of
 4096-byte region [ffff88808ae94200, ffff88808ae95200)
The buggy address belongs to the page:
page:ffffea00022ba500 count:1 mapcount:0 mapping:ffff88812c3f0dc0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea0002265f08 ffffea0002543008 ffff88812c3f0dc0
raw: 0000000000000000 ffff88808ae94200 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808ae94200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808ae94280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808ae94300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88808ae94380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808ae94400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================