Re: [PATCH tty-next] n_tty: Fix termios_rwsem lockdep false positive

2013-08-12 Thread Greg Kroah-Hartman
On Mon, Aug 12, 2013 at 09:39:01AM -0400, Peter Hurley wrote: > On 08/12/2013 09:19 AM, Sergey Senozhatsky wrote: > >On (08/12/13 08:55), Peter Hurley wrote: > >[..] > > drivers/tty/n_tty.c | 25 +++-- > > 1 file changed, 11 insertions(+), 14 deletions(-) > > >

Re: [PATCH tty-next] n_tty: Fix termios_rwsem lockdep false positive

2013-08-12 Thread Peter Hurley
On 08/12/2013 09:19 AM, Sergey Senozhatsky wrote: On (08/12/13 08:55), Peter Hurley wrote: [..] drivers/tty/n_tty.c | 25 +++-- 1 file changed, 11 insertions(+), 14 deletions(-) I hate to do this, but isn't it actually my patch posted here https://lkml.org/lkml/2013/8/1

Re: [PATCH tty-next] n_tty: Fix termios_rwsem lockdep false positive

2013-08-12 Thread Sergey Senozhatsky
On (08/12/13 08:55), Peter Hurley wrote: > >>> [..] > >>> drivers/tty/n_tty.c | 25 +++-- > >>> 1 file changed, 11 insertions(+), 14 deletions(-) > >>> > > > >I hate to do this, but isn't it actually my patch posted here > >https://lkml.org/lkml/2013/8/1/510 > > > >which was ta

Re: [PATCH tty-next] n_tty: Fix termios_rwsem lockdep false positive

2013-08-12 Thread Peter Hurley
On 08/12/2013 06:50 AM, Sergey Senozhatsky wrote: On (08/12/13 13:28), Artem Savkov wrote: Hi Peter, On Sun, Aug 11, 2013 at 08:04:23AM -0400, Peter Hurley wrote: Lockdep reports a circular lock dependency between atomic_read_lock and termios_rwsem [1]. However, a lock order deadlock is not po

Re: [PATCH tty-next] n_tty: Fix termios_rwsem lockdep false positive

2013-08-12 Thread Sergey Senozhatsky
On (08/12/13 13:28), Artem Savkov wrote: > Hi Peter, > > On Sun, Aug 11, 2013 at 08:04:23AM -0400, Peter Hurley wrote: > > Lockdep reports a circular lock dependency between > > atomic_read_lock and termios_rwsem [1]. However, a lock > > order deadlock is not possible since CPU1 only holds a > > r

Re: [PATCH tty-next] n_tty: Fix termios_rwsem lockdep false positive

2013-08-12 Thread Artem Savkov
Hi Peter, On Sun, Aug 11, 2013 at 08:04:23AM -0400, Peter Hurley wrote: > Lockdep reports a circular lock dependency between > atomic_read_lock and termios_rwsem [1]. However, a lock > order deadlock is not possible since CPU1 only holds a > read lock which cannot prevent CPU0 from also acquiring

[PATCH tty-next] n_tty: Fix termios_rwsem lockdep false positive

2013-08-11 Thread Peter Hurley
Lockdep reports a circular lock dependency between atomic_read_lock and termios_rwsem [1]. However, a lock order deadlock is not possible since CPU1 only holds a read lock which cannot prevent CPU0 from also acquiring a read lock on the same r/w semaphore. Unfortunately, lockdep cannot currently d