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From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: Greg KH <gregkh@linuxfoundation.org>,
	arve@android.com, tkjos@android.com, maco@android.com,
	joel@joelfernandes.org, christian@brauner.io, hridya@google.com,
	surenb@google.com
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: [BUG] android: possible ABBA deadlock in print_binder_proc() and binder_get_txn_from_and_acq_inner()
Date: Tue, 7 Sep 2021 10:29:57 +0800	[thread overview]
Message-ID: <303401d0-25c9-d04b-e96d-3ca2aa0a616d@gmail.com> (raw)

Hello,

My static analysis tool reports a possible ABBA deadlock in the android 
driver in Linux 5.10:

print_binder_proc()
   binder_inner_proc_lock()
     _binder_inner_proc_lock()
       spin_lock(&proc->inner_lock); --> Line 662 (Lock A)
   print_binder_thread_ilocked()
     print_binder_transaction_ilocked()
       spin_lock(&t->lock); --> Line 5531 (Lock B)

binder_get_txn_from_and_acq_inner()
   binder_get_txn_from()
     spin_lock(&t->lock); --> Line 1833 (Lock B)
   binder_inner_proc_lock()
     _binder_inner_proc_lock()
       spin_lock(&proc->inner_lock); --> Line 662 (Lock A)

When print_binder_proc() and binder_get_txn_from_and_acq_inner() are 
concurrently executed, the deadlock can occur.

I am not quite sure whether this possible deadlock is real and how to 
fix it if it is real.
Any feedback would be appreciated, thanks :)

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>


Best wishes,
Jia-Ju Bai

             reply	other threads:[~2021-09-07  2:30 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-07  2:29 Jia-Ju Bai [this message]
2021-09-07 19:29 ` [BUG] android: possible ABBA deadlock in print_binder_proc() and binder_get_txn_from_and_acq_inner() Todd Kjos
2021-09-14 10:10   ` Jia-Ju Bai

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