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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:43 [inline]
BUG: KASAN: use-after-free in check_net include/net/net_namespace.h:250 [inline]
BUG: KASAN: use-after-free in rds_destroy_pending net/rds/rds.h:945 [inline]
BUG: KASAN: use-after-free in rds_cong_queue_updates+0x261/0x5e0 net/rds/cong.c:229
Read of size 4 at addr ffff888091094444 by task syz-executor2/22735

CPU: 1 PID: 22735 Comm: syz-executor2 Not tainted 4.20.0+ #391
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+0x1d3/0x2c6 lib/dump_stack.c:113
 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 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:43 [inline]
 check_net include/net/net_namespace.h:250 [inline]
 rds_destroy_pending net/rds/rds.h:945 [inline]
 rds_cong_queue_updates+0x261/0x5e0 net/rds/cong.c:229
 rds_recv_rcvbuf_delta.part.3+0x34f/0x3f0 net/rds/recv.c:118
 rds_recv_rcvbuf_delta net/rds/recv.c:379 [inline]
 rds_recv_incoming+0x8bb/0x1400 net/rds/recv.c:379
 rds_loop_xmit+0xf3/0x2a0 net/rds/loop.c:96
 rds_send_xmit+0x138c/0x29c0 net/rds/send.c:355
 rds_sendmsg+0x36d4/0x4490 net/rds/send.c:1368
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:631
 __sys_sendto+0x3d7/0x670 net/socket.c:1788
hfs: can't find a HFS filesystem on dev loop4
 __do_sys_sendto net/socket.c:1800 [inline]
 __se_sys_sendto net/socket.c:1796 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1796
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4579b9
Code: fd b3 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fb16e3e4c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00000000004579b9
RDX: 0000000000000481 RSI: 0000000020000a00 RDI: 0000000000000009
RBP: 000000000073bf00 R08: 000000002069affb R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb16e3e56d4
R13: 00000000004c4e2b R14: 00000000004d8628 R15: 00000000ffffffff

The buggy address belongs to the page:
page:ffffea0002442500 count:0 mapcount:-128 mapping:0000000000000000 index:0xffff888091094700
flags: 0x1fffc0000000000()
raw: 01fffc0000000000 ffffea0002a12908 ffffea0001ca6908 0000000000000000
raw: ffff888091094700 0000000000000002 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888091094300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888091094380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff888091094400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff888091094480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888091094500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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