KASAN: use-after-free Read in rxrpc_queue_local

Status: fixed on 2019/09/06 20:45
Subsystems: afs net
[Documentation on labels]
Fix commit: 06d9532fa6b3 rxrpc: Fix read-after-free in rxrpc_queue_local()
First crash: 1808d, last: 1808d
Cause bisection: introduced by (bisect log) :
commit b9a1e627405d68d475a3c1f35e685ccfb5bbe668
Author: Cong Wang <>
Date: Thu Jul 4 00:21:13 2019 +0000

  hsr: implement dellink to clean up resources

Crash: general protection fault in send_hsr_supervision_frame (log)
Repro: C syz .config
Discussions (6)
Title Replies (including bot) Last reply
[PATCH AUTOSEL 5.2 01/76] batman-adv: Fix netlink dumping of all mcast_flags buckets 82 (82) 2019/08/30 13:25
[PATCH AUTOSEL 4.19 01/45] net: tundra: tsi108: use spin_lock_irqsave instead of spin_lock_irq in IRQ context 45 (45) 2019/08/29 18:15
[PATCH 4.19 00/98] 4.19.69-stable review 118 (118) 2019/08/28 22:05
[PATCH 5.2 000/162] 5.2.11-stable review 173 (173) 2019/08/28 16:28
[PATCH net 0/2] rxrpc: Fix local endpoint handling 4 (4) 2019/08/15 23:33
KASAN: use-after-free Read in rxrpc_queue_local 1 (4) 2019/08/13 00:36
Last patch testing requests (3)
Created Duration User Patch Repo Result
2019/08/13 21:50 18m git:// 77d3a6b6016874bf1534ed24a1ad991a22e57eac OK
2019/08/13 13:51 14m git:// 544a97bbb91ecf84ac9fe9dc22b7c0065dc02a57 report log
2019/08/12 22:38 15m git:// 03a62469fffcbd535d85e42ef25ba098262e9d72 report log

Sample crash report:
BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
BUG: KASAN: use-after-free in rxrpc_queue_local+0x7c/0x3e0 net/rxrpc/local_object.c:354
Read of size 4 at addr ffff8880a7724014 by task syz-executor522/16188

CPU: 0 PID: 16188 Comm: syz-executor522 Not tainted 5.3.0-rc3+ #159
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+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351
 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482
 kasan_report+0x12/0x17 mm/kasan/common.c:612
 check_memory_region_inline mm/kasan/generic.c:185 [inline]
 check_memory_region+0x134/0x1a0 mm/kasan/generic.c:192
 __kasan_check_read+0x11/0x20 mm/kasan/common.c:92
 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
 rxrpc_queue_local+0x7c/0x3e0 net/rxrpc/local_object.c:354
 rxrpc_unuse_local+0x52/0x80 net/rxrpc/local_object.c:408
 rxrpc_release_sock net/rxrpc/af_rxrpc.c:904 [inline]
 rxrpc_release+0x47d/0x840 net/rxrpc/af_rxrpc.c:930
 __sock_release+0xce/0x280 net/socket.c:590
 sock_close+0x1e/0x30 net/socket.c:1268
 __fput+0x2ff/0x890 fs/file_table.c:280
 ____fput+0x16/0x20 fs/file_table.c:313
 task_work_run+0x145/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x5a9/0x6a0 arch/x86/entry/common.c:299
RIP: 0033:0x407bb1
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 24 1a 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffc861e4d10 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000407bb1
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 0000000000000003
RBP: 00000000006e5a0c R08: 00000000004b1939 R09: 00000000004b1939
R10: 00007ffc861e4d40 R11: 0000000000000293 R12: 00000000006e5a00
R13: 0000000000000000 R14: 000000000000002d R15: 20c49ba5e353f7cf

Allocated by task 16189:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc mm/kasan/common.c:487 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:460
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:501
 kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3550
 kmalloc include/linux/slab.h:552 [inline]
 kzalloc include/linux/slab.h:748 [inline]
 rxrpc_alloc_local net/rxrpc/local_object.c:79 [inline]
 rxrpc_lookup_local+0x562/0x1b70 net/rxrpc/local_object.c:277
 rxrpc_bind+0x34d/0x5e0 net/rxrpc/af_rxrpc.c:149
 __sys_bind+0x239/0x290 net/socket.c:1647
 __do_sys_bind net/socket.c:1658 [inline]
 __se_sys_bind net/socket.c:1656 [inline]
 __x64_sys_bind+0x73/0xb0 net/socket.c:1656
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296

Freed by task 9:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:449
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:457
 __cache_free mm/slab.c:3425 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3756
 rxrpc_local_rcu+0x62/0x80 net/rxrpc/local_object.c:495
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch kernel/rcu/tree.c:2114 [inline]
 rcu_core+0x67f/0x1580 kernel/rcu/tree.c:2314
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2323
 __do_softirq+0x262/0x98c kernel/softirq.c:292

The buggy address belongs to the object at ffff8880a7724000
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 20 bytes inside of
 1024-byte region [ffff8880a7724000, ffff8880a7724400)
The buggy address belongs to the page:
page:ffffea00029dc900 refcount:1 mapcount:0 mapping:ffff8880aa400c40 index:0xffff8880a7725200 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea0002a6ad08 ffffea0002a6a808 ffff8880aa400c40
raw: ffff8880a7725200 ffff8880a7724000 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a7723f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a7723f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a7724000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a7724080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a7724100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/08/12 10:03 net-old 125b7e0949d4 acb51638 .config console log report syz C ci-upstream-net-this-kasan-gce
* Struck through repros no longer work on HEAD.