KASAN: use-after-free Read in rxrpc_put_peer

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: ed2393ca Add linux-next specific files for 20190827
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11b4a79c600000
kernel config: https://syzkaller.appspot.com/x/.config?x=2ef5940a07ed45f4
dashboard link: https://syzkaller.appspot.com/bug?extid=b9be979c55f2bea8ed30
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13c73066600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+b9be97...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in __rxrpc_put_peer net/rxrpc/peer_object.c:411
[inline]
BUG: KASAN: use-after-free in rxrpc_put_peer+0x685/0x6a0
net/rxrpc/peer_object.c:435
Read of size 8 at addr ffff8880a05bd218 by task ksoftirqd/1/16

CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.3.0-rc6-next-20190827 #74
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.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
__kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
kasan_report+0x12/0x20 mm/kasan/common.c:634
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
__rxrpc_put_peer net/rxrpc/peer_object.c:411 [inline]
rxrpc_put_peer+0x685/0x6a0 net/rxrpc/peer_object.c:435
rxrpc_rcu_destroy_call+0x5e/0x140 net/rxrpc/call_object.c:566
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2157 [inline]
rcu_core+0x581/0x1560 kernel/rcu/tree.c:2377
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2386
__do_softirq+0x262/0x98c kernel/softirq.c:292
run_ksoftirqd kernel/softirq.c:603 [inline]
run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595
smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165
kthread+0x361/0x430 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 17189:
save_stack+0x23/0x90 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:510 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:483
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3550
kmalloc include/linux/slab.h:552 [inline]
kzalloc include/linux/slab.h:686 [inline]
rxrpc_alloc_local net/rxrpc/local_object.c:79 [inline]
rxrpc_lookup_local+0x562/0x1ba0 net/rxrpc/local_object.c:277
rxrpc_sendmsg+0x379/0x5f0 net/rxrpc/af_rxrpc.c:566
sock_sendmsg_nosec net/socket.c:637 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:657
___sys_sendmsg+0x3e2/0x920 net/socket.c:2311
__sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2413
__do_sys_sendmmsg net/socket.c:2442 [inline]
__se_sys_sendmmsg net/socket.c:2439 [inline]
__x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2439
do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9:
save_stack+0x23/0x90 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
kasan_set_free_info mm/kasan/common.c:332 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:471
kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
__cache_free mm/slab.c:3425 [inline]
kfree+0x10a/0x2c0 mm/slab.c:3756
rxrpc_local_rcu+0x62/0x80 net/rxrpc/local_object.c:499
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2157 [inline]
rcu_core+0x581/0x1560 kernel/rcu/tree.c:2377
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2386
__do_softirq+0x262/0x98c kernel/softirq.c:292

The buggy address belongs to the object at ffff8880a05bd200
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 24 bytes inside of
1024-byte region [ffff8880a05bd200, ffff8880a05bd600)
The buggy address belongs to the page:
page:ffffea0002816f00 refcount:1 mapcount:0 mapping:ffff8880aa400c40
index:0xffff8880a05bcd80 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00027c4588 ffffea0002381088 ffff8880aa400c40
raw: ffff8880a05bcd80 ffff8880a05bc000 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8880a05bd100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880a05bd180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8880a05bd200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880a05bd280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880a05bd300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

[David Howells]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git 48b9e92aeb3c2b0df3454faf9024f6ca611d65a3

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger
crash:

Reported-and-tested-by:
syzbot+b9be97...@syzkaller.appspotmail.com

Tested on:

commit: 48b9e92a rxrpc: Fix lack of conn cleanup when local endpoi..
git tree:
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
kernel config: https://syzkaller.appspot.com/x/.config?x=230542aa16bfc4b0

dashboard link: https://syzkaller.appspot.com/bug?extid=b9be979c55f2bea8ed30
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

Note: testing is done by a robot and is best-effort only.

[syzbot]

syzbot has found a reproducer for the following crash on:

HEAD commit: a3c0e7b1 Merge tag 'libnvdimm-fixes-5.4-rc1' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1622045d600000
kernel config: https://syzkaller.appspot.com/x/.config?x=6ffbfa7e4a36190f

dashboard link: https://syzkaller.appspot.com/bug?extid=b9be979c55f2bea8ed30
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11b8f605600000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10547843600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+b9be97...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in __rxrpc_put_peer net/rxrpc/peer_object.c:411
[inline]
BUG: KASAN: use-after-free in rxrpc_put_peer+0x685/0x6a0
net/rxrpc/peer_object.c:435

Read of size 8 at addr ffff888097ec0058 by task syz-executor823/24216

CPU: 0 PID: 24216 Comm: syz-executor823 Not tainted 5.3.0+ #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:

<IRQ>

__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x172/0x1f0 lib/dump_stack.c:113
print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
__kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
kasan_report+0x12/0x20 mm/kasan/common.c:634
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
__rxrpc_put_peer net/rxrpc/peer_object.c:411 [inline]
rxrpc_put_peer+0x685/0x6a0 net/rxrpc/peer_object.c:435
rxrpc_rcu_destroy_call+0x5e/0x140 net/rxrpc/call_object.c:566
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2157 [inline]
rcu_core+0x581/0x1560 kernel/rcu/tree.c:2377
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2386
__do_softirq+0x262/0x98c kernel/softirq.c:292

invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x19b/0x1e0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:536 [inline]
smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830
</IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:756
[inline]
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160
[inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x95/0xe0
kernel/locking/spinlock.c:191
Code: 48 c7 c0 20 1c f3 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c
10 00 75 39 48 83 3d 92 28 ac 01 00 74 24 48 89 df 57 9d <0f> 1f 44 00 00
bf 01 00 00 00 e8 ec 10 08 fa 65 8b 05 5d 0a bb 78
RSP: 0018:ffff8880927378c0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11e6384 RBX: 0000000000000286 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000006 RDI: 0000000000000286
RBP: ffff8880927378d0 R08: ffff888097632000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff8ac62ca8
R13: ffffffff8ac62ca8 R14: ffff888083be9000 R15: 0000000000000003
__debug_check_no_obj_freed lib/debugobjects.c:973 [inline]
debug_check_no_obj_freed+0x20a/0x43f lib/debugobjects.c:994
free_pages_prepare mm/page_alloc.c:1175 [inline]
__free_pages_ok+0x266/0xea0 mm/page_alloc.c:1421
free_compound_page+0x97/0xd0 mm/page_alloc.c:674
free_transhuge_page+0x2a7/0x3b0 mm/huge_memory.c:2842
__put_compound_page+0x90/0xd0 mm/swap.c:97
release_pages+0x5e5/0x1a50 mm/swap.c:810
free_pages_and_swap_cache+0x2c3/0x3f0 mm/swap_state.c:296
tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:184 [inline]
tlb_flush_mmu+0x89/0x630 mm/mmu_gather.c:191
tlb_finish_mmu+0x98/0x3b0 mm/mmu_gather.c:272
exit_mmap+0x2da/0x530 mm/mmap.c:3163
__mmput kernel/fork.c:1079 [inline]
mmput+0x179/0x4d0 kernel/fork.c:1100
exit_mm kernel/exit.c:485 [inline]
do_exit+0x823/0x2e60 kernel/exit.c:804
do_group_exit+0x135/0x360 kernel/exit.c:921
__do_sys_exit_group kernel/exit.c:932 [inline]
__se_sys_exit_group kernel/exit.c:930 [inline]
__x64_sys_exit_group+0x44/0x50 kernel/exit.c:930
do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x440078
Code: 00 00 be 3c 00 00 00 eb 19 66 0f 1f 84 00 00 00 00 00 48 89 d7 89 f0
0f 05 48 3d 00 f0 ff ff 77 21 f4 48 89 d7 44 89 c0 0f 05 <48> 3d 00 f0 ff
ff 76 e0 f7 d8 64 41 89 01 eb d8 0f 1f 84 00 00 00
RSP: 002b:00007ffd29763d08 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000440078
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004bfa50 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 24200:

save_stack+0x23/0x90 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:510 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:483
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3550
kmalloc include/linux/slab.h:552 [inline]
kzalloc include/linux/slab.h:686 [inline]
rxrpc_alloc_local net/rxrpc/local_object.c:79 [inline]
rxrpc_lookup_local+0x562/0x1ba0 net/rxrpc/local_object.c:277
rxrpc_sendmsg+0x379/0x5f0 net/rxrpc/af_rxrpc.c:566
sock_sendmsg_nosec net/socket.c:637 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:657
___sys_sendmsg+0x3e2/0x920 net/socket.c:2311
__sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2413
__do_sys_sendmmsg net/socket.c:2442 [inline]
__se_sys_sendmmsg net/socket.c:2439 [inline]
__x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2439
do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 16:

save_stack+0x23/0x90 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
kasan_set_free_info mm/kasan/common.c:332 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:471
kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
__cache_free mm/slab.c:3425 [inline]
kfree+0x10a/0x2c0 mm/slab.c:3756
rxrpc_local_rcu+0x62/0x80 net/rxrpc/local_object.c:499
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2157 [inline]
rcu_core+0x581/0x1560 kernel/rcu/tree.c:2377
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2386
__do_softirq+0x262/0x98c kernel/softirq.c:292

The buggy address belongs to the object at ffff888097ec0040

which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 24 bytes inside of

1024-byte region [ffff888097ec0040, ffff888097ec0440)

The buggy address belongs to the page:

page:ffffea00025fb000 refcount:1 mapcount:0 mapping:ffff8880aa400c40
index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00025bf208 ffffea0002605e88 ffff8880aa400c40
raw: 0000000000000000 ffff888097ec0040 0000000100000007 0000000000000000

page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff888097ebff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888097ebff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> ffff888097ec0000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
^
ffff888097ec0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888097ec0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

[David Howells]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git cc9604d48fc3b73d9665ae80a2f07dc3fc0574c4

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
KASAN: use-after-free Read in rxrpc_release_call

==================================================================
BUG: KASAN: use-after-free in rxrpc_release_call+0x973/0xaa0
net/rxrpc/call_object.c:498
Read of size 8 at addr ffff88808888b910 by task syz-executor.5/9000

CPU: 1 PID: 9000 Comm: syz-executor.5 Not tainted 5.3.0+ #0

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.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
__kasan_report.cold+0x1b/0x41 mm/kasan/report.c:506
kasan_report+0x12/0x20 mm/kasan/common.c:634
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132

rxrpc_release_call+0x973/0xaa0 net/rxrpc/call_object.c:498
rxrpc_release_calls_on_socket+0x6e7/0x1320 net/rxrpc/call_object.c:528
rxrpc_release_sock net/rxrpc/af_rxrpc.c:897 [inline]
rxrpc_release+0x2a6/0x550 net/rxrpc/af_rxrpc.c:927
__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+0x65f/0x760 arch/x86/entry/common.c:300
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459a29
Code: fd b7 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 b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f6e3d494c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000459a29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6e3d4956d4
R13: 00000000004f93d2 R14: 00000000004d1e00 R15: 00000000ffffffff

Allocated by task 9000:

save_stack+0x23/0x90 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:510 [inline]
__kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:483
kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3550
kmalloc include/linux/slab.h:552 [inline]
kzalloc include/linux/slab.h:686 [inline]

rxrpc_alloc_connection+0x86/0x5f0 net/rxrpc/conn_object.c:41
rxrpc_alloc_client_connection net/rxrpc/conn_client.c:176 [inline]
rxrpc_get_client_conn net/rxrpc/conn_client.c:340 [inline]
rxrpc_connect_call+0x648/0x4c30 net/rxrpc/conn_client.c:698
rxrpc_new_client_call+0x9c0/0x1ad0 net/rxrpc/call_object.c:290
rxrpc_new_client_call_for_sendmsg net/rxrpc/sendmsg.c:595 [inline]
rxrpc_do_sendmsg+0xffa/0x1d5f net/rxrpc/sendmsg.c:652
rxrpc_sendmsg+0x4d6/0x5f0 net/rxrpc/af_rxrpc.c:585

sock_sendmsg_nosec net/socket.c:637 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:657
___sys_sendmsg+0x3e2/0x920 net/socket.c:2311
__sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2413
__do_sys_sendmmsg net/socket.c:2442 [inline]
__se_sys_sendmmsg net/socket.c:2439 [inline]
__x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2439
do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 16:
save_stack+0x23/0x90 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
kasan_set_free_info mm/kasan/common.c:332 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:471
kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
__cache_free mm/slab.c:3425 [inline]
kfree+0x10a/0x2c0 mm/slab.c:3756

rxrpc_destroy_connection+0x1f2/0x2d0 net/rxrpc/conn_object.c:373

__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2157 [inline]
rcu_core+0x581/0x1560 kernel/rcu/tree.c:2377
rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2386
__do_softirq+0x262/0x98c kernel/softirq.c:292

The buggy address belongs to the object at ffff88808888b6c0

which belongs to the cache kmalloc-1k of size 1024

The buggy address is located 592 bytes inside of
1024-byte region [ffff88808888b6c0, ffff88808888bac0)

The buggy address belongs to the page:

page:ffffea0002222280 refcount:1 mapcount:0 mapping:ffff8880aa400c40
index:0xffff88808888bb40 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea000220ae88 ffffea0002809108 ffff8880aa400c40
raw: ffff88808888bb40 ffff88808888a040 0000000100000002 0000000000000000

page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff88808888b800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88808888b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff88808888b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88808888b980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88808888ba00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit: cc9604d4 rxrpc: rxrpc_peer needs to hold a ref on the rxrp..
git tree:
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
console output: https://syzkaller.appspot.com/x/log.txt?x=126c3899600000

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger
crash:

Reported-and-tested-by:
syzbot+b9be97...@syzkaller.appspotmail.com

Tested on:

commit: 37932e65 rxrpc: Fix call crypto state cleanup
git tree:
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git

kernel config: https://syzkaller.appspot.com/x/.config?x=6ffbfa7e4a36190f
dashboard link: https://syzkaller.appspot.com/bug?extid=b9be979c55f2bea8ed30
compiler: gcc (GCC) 9.0.0 20181231 (experimental)