On Wed, Jan 20, 2016 at 5:08 PM, Peter Hurley <[email protected]> wrote: > On 01/20/2016 05:02 AM, Peter Zijlstra wrote: >> On Wed, Dec 30, 2015 at 11:44:01AM +0100, Dmitry Vyukov wrote: >>> -> #3 (&buf->lock){+.+...}: >>> [<ffffffff813f0acf>] lock_acquire+0x19f/0x3c0 >>> kernel/locking/lockdep.c:3585 >>> [< inline >] __raw_spin_lock_irqsave >>> include/linux/spinlock_api_smp.h:112 >>> [<ffffffff85c8e790>] _raw_spin_lock_irqsave+0x50/0x70 >>> kernel/locking/spinlock.c:159 >>> [<ffffffff82b8c050>] tty_get_pgrp+0x20/0x80 drivers/tty/tty_io.c:2502 >> >> So in any recent code that I look at this function tries to acquire >> tty->ctrl_lock, not buf->lock. Am I missing something ?! > > Yes. > > The tty locks were annotated with __lockfunc so were being elided from lockdep > stacktraces. Greg has a patch in his queue from me that removes the __lockfunc > annotation ("tty: Remove __lockfunc annotation from tty lock functions"). > > Unfortunately, I think syzkaller's post-processing stack trace isn't helping > either, giving the impression that the stack is still inside tty_get_pgrp(). > > It's not.
I've got a new report on commit a200dcb34693084e56496960d855afdeaaf9578f (Jan 18). Here is unprocessed version: https://gist.githubusercontent.com/dvyukov/428a0c9bfaa867d8ce84/raw/0754db31668602ad07947f9964238b2f9cf63315/gistfile1.txt and here is processed one: https://gist.githubusercontent.com/dvyukov/42b874213de82d94c35e/raw/2bbced252035821243678de0112e2ed3a766fb5d/gistfile1.txt Peter, what exactly is wrong with the post-processed version? I would be interested in fixing the processing script. As far as I see it contains the same stacks just with line numbers and inlined frames. I am using a significantly different compilation mode (kasan + kcov + very recent gcc), so nobody except me won't be able to figure out line numbers based on offsets.
