IO-Uring Archive on lore.kernel.org
 help / color / Atom feed
* KASAN: use-after-free Read in io_wq_flush
@ 2019-12-20 21:35 syzbot
  2019-12-20 21:58 ` Jens Axboe
  0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2019-12-20 21:35 UTC (permalink / raw)
  To: axboe, io-uring, linux-fsdevel, linux-kernel, syzkaller-bugs, viro

Hello,

syzbot found the following crash on:

HEAD commit:    7ddd09fc Add linux-next specific files for 20191220
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11a074c1e00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f183b01c3088afc6
dashboard link: https://syzkaller.appspot.com/bug?extid=a2cf8365eb32fc6dbb5e
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1190743ee00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12b97f1ee00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+a2cf8365eb32fc6dbb5e@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in io_wq_flush+0x1f7/0x210 fs/io-wq.c:1009
Read of size 8 at addr ffff88809ea14b00 by task kworker/1:2/2797

CPU: 1 PID: 2797 Comm: kworker/1:2 Not tainted  
5.5.0-rc2-next-20191220-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: events io_ring_file_ref_switch
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x197/0x210 lib/dump_stack.c:118
  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:639
  __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
  io_wq_flush+0x1f7/0x210 fs/io-wq.c:1009
  io_destruct_skb+0x8e/0xc0 fs/io_uring.c:4668
  skb_release_head_state+0xeb/0x260 net/core/skbuff.c:652
  skb_release_all+0x16/0x60 net/core/skbuff.c:663
  __kfree_skb net/core/skbuff.c:679 [inline]
  kfree_skb net/core/skbuff.c:697 [inline]
  kfree_skb+0x101/0x420 net/core/skbuff.c:691
  io_ring_file_put fs/io_uring.c:4836 [inline]
  io_ring_file_ref_switch+0x68a/0xac0 fs/io_uring.c:4881
  process_one_work+0x9af/0x1740 kernel/workqueue.c:2264
  worker_thread+0x98/0xe40 kernel/workqueue.c:2410
  kthread+0x361/0x430 kernel/kthread.c:255
  ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 9381:
  save_stack+0x23/0x90 mm/kasan/common.c:72
  set_track mm/kasan/common.c:80 [inline]
  __kasan_kmalloc mm/kasan/common.c:513 [inline]
  __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
  kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
  kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551
  kmalloc include/linux/slab.h:555 [inline]
  kzalloc include/linux/slab.h:669 [inline]
  io_wq_create+0x52/0xa40 fs/io-wq.c:1024
  io_sq_offload_start fs/io_uring.c:5244 [inline]
  io_uring_create fs/io_uring.c:6002 [inline]
  io_uring_setup+0xf4a/0x2080 fs/io_uring.c:6062
  __do_sys_io_uring_setup fs/io_uring.c:6075 [inline]
  __se_sys_io_uring_setup fs/io_uring.c:6072 [inline]
  __x64_sys_io_uring_setup+0x54/0x80 fs/io_uring.c:6072
  do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9381:
  save_stack+0x23/0x90 mm/kasan/common.c:72
  set_track mm/kasan/common.c:80 [inline]
  kasan_set_free_info mm/kasan/common.c:335 [inline]
  __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
  kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
  __cache_free mm/slab.c:3426 [inline]
  kfree+0x10a/0x2c0 mm/slab.c:3757
  io_wq_destroy+0x2ce/0x3c0 fs/io-wq.c:1116
  io_finish_async+0x128/0x1b0 fs/io_uring.c:4657
  io_ring_ctx_free fs/io_uring.c:5569 [inline]
  io_ring_ctx_wait_and_kill+0x330/0x9a0 fs/io_uring.c:5644
  io_uring_release+0x42/0x50 fs/io_uring.c:5652
  __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:164
  prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
  syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
  do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88809ea14b00
  which belongs to the cache kmalloc-192 of size 192
The buggy address is located 0 bytes inside of
  192-byte region [ffff88809ea14b00, ffff88809ea14bc0)
The buggy address belongs to the page:
page:ffffea00027a8500 refcount:1 mapcount:0 mapping:ffff8880aa400000  
index:0x0
raw: 00fffe0000000200 ffffea00027a8148 ffffea00027a8f08 ffff8880aa400000
raw: 0000000000000000 ffff88809ea14000 0000000100000010 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
  ffff88809ea14a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffff88809ea14a80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
> ffff88809ea14b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                    ^
  ffff88809ea14b80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
  ffff88809ea14c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================


---
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 syzkaller@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

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: KASAN: use-after-free Read in io_wq_flush
  2019-12-20 21:35 KASAN: use-after-free Read in io_wq_flush syzbot
@ 2019-12-20 21:58 ` Jens Axboe
  0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2019-12-20 21:58 UTC (permalink / raw)
  To: syzbot, io-uring, linux-fsdevel, linux-kernel, syzkaller-bugs, viro

On 12/20/19 2:35 PM, syzbot wrote:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:    7ddd09fc Add linux-next specific files for 20191220
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=11a074c1e00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=f183b01c3088afc6
> dashboard link: https://syzkaller.appspot.com/bug?extid=a2cf8365eb32fc6dbb5e
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1190743ee00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12b97f1ee00000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+a2cf8365eb32fc6dbb5e@syzkaller.appspotmail.com
> 
> ==================================================================
> BUG: KASAN: use-after-free in io_wq_flush+0x1f7/0x210 fs/io-wq.c:1009
> Read of size 8 at addr ffff88809ea14b00 by task kworker/1:2/2797
> 
> CPU: 1 PID: 2797 Comm: kworker/1:2 Not tainted  
> 5.5.0-rc2-next-20191220-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
> Google 01/01/2011
> Workqueue: events io_ring_file_ref_switch
> Call Trace:
>   __dump_stack lib/dump_stack.c:77 [inline]
>   dump_stack+0x197/0x210 lib/dump_stack.c:118
>   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:639
>   __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
>   io_wq_flush+0x1f7/0x210 fs/io-wq.c:1009
>   io_destruct_skb+0x8e/0xc0 fs/io_uring.c:4668
>   skb_release_head_state+0xeb/0x260 net/core/skbuff.c:652
>   skb_release_all+0x16/0x60 net/core/skbuff.c:663
>   __kfree_skb net/core/skbuff.c:679 [inline]
>   kfree_skb net/core/skbuff.c:697 [inline]
>   kfree_skb+0x101/0x420 net/core/skbuff.c:691
>   io_ring_file_put fs/io_uring.c:4836 [inline]
>   io_ring_file_ref_switch+0x68a/0xac0 fs/io_uring.c:4881
>   process_one_work+0x9af/0x1740 kernel/workqueue.c:2264
>   worker_thread+0x98/0xe40 kernel/workqueue.c:2410
>   kthread+0x361/0x430 kernel/kthread.c:255
>   ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
> 
> Allocated by task 9381:
>   save_stack+0x23/0x90 mm/kasan/common.c:72
>   set_track mm/kasan/common.c:80 [inline]
>   __kasan_kmalloc mm/kasan/common.c:513 [inline]
>   __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486
>   kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
>   kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551
>   kmalloc include/linux/slab.h:555 [inline]
>   kzalloc include/linux/slab.h:669 [inline]
>   io_wq_create+0x52/0xa40 fs/io-wq.c:1024
>   io_sq_offload_start fs/io_uring.c:5244 [inline]
>   io_uring_create fs/io_uring.c:6002 [inline]
>   io_uring_setup+0xf4a/0x2080 fs/io_uring.c:6062
>   __do_sys_io_uring_setup fs/io_uring.c:6075 [inline]
>   __se_sys_io_uring_setup fs/io_uring.c:6072 [inline]
>   __x64_sys_io_uring_setup+0x54/0x80 fs/io_uring.c:6072
>   do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
>   entry_SYSCALL_64_after_hwframe+0x49/0xbe
> 
> Freed by task 9381:
>   save_stack+0x23/0x90 mm/kasan/common.c:72
>   set_track mm/kasan/common.c:80 [inline]
>   kasan_set_free_info mm/kasan/common.c:335 [inline]
>   __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474
>   kasan_slab_free+0xe/0x10 mm/kasan/common.c:483
>   __cache_free mm/slab.c:3426 [inline]
>   kfree+0x10a/0x2c0 mm/slab.c:3757
>   io_wq_destroy+0x2ce/0x3c0 fs/io-wq.c:1116
>   io_finish_async+0x128/0x1b0 fs/io_uring.c:4657
>   io_ring_ctx_free fs/io_uring.c:5569 [inline]
>   io_ring_ctx_wait_and_kill+0x330/0x9a0 fs/io_uring.c:5644
>   io_uring_release+0x42/0x50 fs/io_uring.c:5652
>   __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:164
>   prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
>   syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
>   do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304
>   entry_SYSCALL_64_after_hwframe+0x49/0xbe
> 
> The buggy address belongs to the object at ffff88809ea14b00
>   which belongs to the cache kmalloc-192 of size 192
> The buggy address is located 0 bytes inside of
>   192-byte region [ffff88809ea14b00, ffff88809ea14bc0)
> The buggy address belongs to the page:
> page:ffffea00027a8500 refcount:1 mapcount:0 mapping:ffff8880aa400000  
> index:0x0
> raw: 00fffe0000000200 ffffea00027a8148 ffffea00027a8f08 ffff8880aa400000
> raw: 0000000000000000 ffff88809ea14000 0000000100000010 0000000000000000
> page dumped because: kasan: bad access detected
> 
> Memory state around the buggy address:
>   ffff88809ea14a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>   ffff88809ea14a80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>> ffff88809ea14b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                     ^
>   ffff88809ea14b80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>   ffff88809ea14c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ==================================================================

#syz invalid

This is fixed in the current tree, pushing out a new linux-next
branch.

-- 
Jens Axboe


^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, back to index

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-12-20 21:35 KASAN: use-after-free Read in io_wq_flush syzbot
2019-12-20 21:58 ` Jens Axboe

IO-Uring Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/io-uring/0 io-uring/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 io-uring io-uring/ https://lore.kernel.org/io-uring \
		io-uring@vger.kernel.org
	public-inbox-index io-uring

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.io-uring


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git