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Message-ID: <1d287c7e-8aff-beea-1bd6-4b2226f9f3db@opensource.wdc.com>
Date:   Thu, 17 Feb 2022 19:49:11 +0900
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
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Subject: Re: [PATCH RESEND v2] dm: Fix use-after-free in
 dm_cleanup_zoned_dev()
Content-Language: en-US
To:     Kirill Tkhai <ktkhai@virtuozzo.com>,
        "agk@redhat.com" <agk@redhat.com>,
        "snitzer@redhat.com" <snitzer@redhat.com>,
        "dm-devel@redhat.com" <dm-devel@redhat.com>,
        linux-kernel@vger.kernel.org
References: <c64d2143-284e-7621-440c-971e3405b4d8@virtuozzo.com>
 <d209a0b1-2514-79a0-257a-22bcb372785a@virtuozzo.com>
From:   Damien Le Moal <damien.lemoal@opensource.wdc.com>
Organization: Western Digital Research
In-Reply-To: <d209a0b1-2514-79a0-257a-22bcb372785a@virtuozzo.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 2/17/22 19:13, Kirill Tkhai wrote:
> 
> dm_cleanup_zoned_dev() uses queue, so it must be called
> before blk_cleanup_disk() starts its killing:
> 
> blk_cleanup_disk->blk_cleanup_queue()->kobject_put()->blk_release_queue()->
> ->...RCU...->blk_free_queue_rcu()->kmem_cache_free()
> 
> Otherwise, RCU callback may be executed first,
> and dm_cleanup_zoned_dev() touches freed memory:

Mike,

Can you queue this please ?

> 
>  BUG: KASAN: use-after-free in dm_cleanup_zoned_dev+0x33/0xd0
>  Read of size 8 at addr ffff88805ac6e430 by task dmsetup/681
> 
>  CPU: 4 PID: 681 Comm: dmsetup Not tainted 5.17.0-rc2+ #6
>  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
>  Call Trace:
>   <TASK>
>   dump_stack_lvl+0x57/0x7d
>   print_address_description.constprop.0+0x1f/0x150
>   ? dm_cleanup_zoned_dev+0x33/0xd0
>   kasan_report.cold+0x7f/0x11b
>   ? dm_cleanup_zoned_dev+0x33/0xd0
>   dm_cleanup_zoned_dev+0x33/0xd0
>   __dm_destroy+0x26a/0x400
>   ? dm_blk_ioctl+0x230/0x230
>   ? up_write+0xd8/0x270
>   dev_remove+0x156/0x1d0
>   ctl_ioctl+0x269/0x530
>   ? table_clear+0x140/0x140
>   ? lock_release+0xb2/0x750
>   ? remove_all+0x40/0x40
>   ? rcu_read_lock_sched_held+0x12/0x70
>   ? lock_downgrade+0x3c0/0x3c0
>   ? rcu_read_lock_sched_held+0x12/0x70
>   dm_ctl_ioctl+0xa/0x10
>   __x64_sys_ioctl+0xb9/0xf0
>   do_syscall_64+0x3b/0x90
>   entry_SYSCALL_64_after_hwframe+0x44/0xae
>  RIP: 0033:0x7fb6dfa95c27
>  Code: 00 00 00 48 8b 05 69 92 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 39 92 0c 00 f7 d8 64 89 01 48
>  RSP: 002b:00007fff882c6c28 EFLAGS: 00000206 ORIG_RAX: 0000000000000010
>  RAX: ffffffffffffffda RBX: 00007fb6dfb73a8e RCX: 00007fb6dfa95c27
>  RDX: 00007fb6e01d7ca0 RSI: 00000000c138fd04 RDI: 0000000000000003
>  RBP: 00007fff882c6ce0 R08: 00007fb6dfbc3558 R09: 00007fff882c6a90
>  R10: 00007fb6dfbc28a2 R11: 0000000000000206 R12: 00007fb6dfbc28a2
>  R13: 00007fb6dfbc28a2 R14: 00007fb6dfbc28a2 R15: 00007fb6dfbc28a2
>   </TASK>
> 
>  Allocated by task 673:
>   kasan_save_stack+0x1e/0x40
>   __kasan_slab_alloc+0x66/0x80
>   kmem_cache_alloc_node+0x1ca/0x460
>   blk_alloc_queue+0x33/0x4e0
>   __blk_alloc_disk+0x1b/0x60
>   dm_create+0x368/0xa20
>   dev_create+0xb9/0x170
>   ctl_ioctl+0x269/0x530
>   dm_ctl_ioctl+0xa/0x10
>   __x64_sys_ioctl+0xb9/0xf0
>   do_syscall_64+0x3b/0x90
>   entry_SYSCALL_64_after_hwframe+0x44/0xae
> 
>  Freed by task 0:
>   kasan_save_stack+0x1e/0x40
>   kasan_set_track+0x21/0x30
>   kasan_set_free_info+0x20/0x30
>   __kasan_slab_free+0xfb/0x130
>   slab_free_freelist_hook+0x7d/0x150
>   kmem_cache_free+0x13c/0x340
>   rcu_do_batch+0x2d9/0x820
>   rcu_core+0x3b8/0x570
>   __do_softirq+0x1c4/0x63d
> 
>  Last potentially related work creation:
>   kasan_save_stack+0x1e/0x40
>   __kasan_record_aux_stack+0x96/0xa0
>   call_rcu+0xc4/0x8f0
>   kobject_put+0xd9/0x270
>   disk_release+0xee/0x120
>   device_release+0x59/0xf0
>   kobject_put+0xd9/0x270
>   cleanup_mapped_device+0x12b/0x1b0
>   __dm_destroy+0x26a/0x400
>   dev_remove+0x156/0x1d0
>   ctl_ioctl+0x269/0x530
>   dm_ctl_ioctl+0xa/0x10
>   __x64_sys_ioctl+0xb9/0xf0
>   do_syscall_64+0x3b/0x90
>   entry_SYSCALL_64_after_hwframe+0x44/0xae
> 
>  The buggy address belongs to the object at ffff88805ac6e180
>   which belongs to the cache request_queue of size 2992
>  The buggy address is located 688 bytes inside of
>   2992-byte region [ffff88805ac6e180, ffff88805ac6ed30)
>  The buggy address belongs to the page:
>  page:000000000837df3c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5ac68
>  head:000000000837df3c order:3 compound_mapcount:0 compound_pincount:0
>  flags: 0xfffffc0010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff)
>  raw: 000fffffc0010200 0000000000000000 dead000000000122 ffff888001e58280
>  raw: 0000000000000000 00000000800a000a 00000001ffffffff 0000000000000000
>  page dumped because: kasan: bad access detected
> 
>  Memory state around the buggy address:
>   ffff88805ac6e300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>   ffff88805ac6e380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>  >ffff88805ac6e400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                                       ^
>   ffff88805ac6e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>   ffff88805ac6e500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>  ==================================================================
> 
> Fixes: bb37d77239af "dm: introduce zone append emulation"
> Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
> Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> ---
> v2: Split long commit message line and delete [xxx] time prefix from kernel output.
> 
>  drivers/md/dm.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index dcbd6d201619..d472fe5dbc1d 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -1607,6 +1607,7 @@ static void cleanup_mapped_device(struct mapped_device *md)
>  		md->dax_dev = NULL;
>  	}
>  
> +	dm_cleanup_zoned_dev(md);
>  	if (md->disk) {
>  		spin_lock(&_minor_lock);
>  		md->disk->private_data = NULL;
> @@ -1627,7 +1628,6 @@ static void cleanup_mapped_device(struct mapped_device *md)
>  	mutex_destroy(&md->swap_bios_lock);
>  
>  	dm_mq_cleanup_mapped_device(md);
> -	dm_cleanup_zoned_dev(md);
>  }
>  
>  /*
> 


-- 
Damien Le Moal
Western Digital Research