Re: [PATCH] RFC: console: hack up console_lock more v3

2019-05-11 Thread Sergey Senozhatsky
On (05/10/19 11:15), Petr Mladek wrote: [..] > arch/x86/kernel/smp.c |3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > --- a/arch/x86/kernel/smp.c > +++ b/arch/x86/kernel/smp.c > @@ -124,7 +124,8 @@ static bool smp_no_nmi_ipi = false; > */ > static void native_smp_send_reschedul

Re: [PATCH] RFC: console: hack up console_lock more v3

2019-05-11 Thread Petr Mladek
On Thu 2019-05-09 18:43:12, Daniel Vetter wrote: > One thing to keep in mind is that the kernel is already dying, and > things will come crashing down later on This is important information. I havn't seen it mentioned earlier. > (I've seen this only in dmesg > tails capture in pstore in our CI, i

Re: [PATCH] RFC: console: hack up console_lock more v3

2019-05-10 Thread Daniel Vetter
On Fri, May 10, 2019 at 11:15 AM Petr Mladek wrote: > On Thu 2019-05-09 18:43:12, Daniel Vetter wrote: > > One thing to keep in mind is that the kernel is already dying, and > > things will come crashing down later on > > This is important information. I havn't seen it mentioned earlier. I though

Re: [PATCH] RFC: console: hack up console_lock more v3

2019-05-09 Thread Petr Mladek
On Thu 2019-05-09 14:09:03, Daniel Vetter wrote: > console_trylock, called from within printk, can be called from pretty > much anywhere. Including try_to_wake_up. Note that this isn't common, > usually the box is in pretty bad shape at that point already. But it > really doesn't help when then loc

Re: [PATCH] RFC: console: hack up console_lock more v3

2019-05-09 Thread Daniel Vetter
On Thu, May 9, 2019 at 4:56 PM Petr Mladek wrote: > > On Thu 2019-05-09 14:09:03, Daniel Vetter wrote: > > console_trylock, called from within printk, can be called from pretty > > much anywhere. Including try_to_wake_up. Note that this isn't common, > > usually the box is in pretty bad shape at t

Re: [PATCH] RFC: console: hack up console_lock more v3

2019-05-09 Thread Peter Zijlstra
On Thu, May 09, 2019 at 03:06:09PM +0200, Daniel Vetter wrote: > On Thu, May 9, 2019 at 2:31 PM Peter Zijlstra wrote: > > On Thu, May 09, 2019 at 02:09:03PM +0200, Daniel Vetter wrote: > > > Fix this by creating a prinkt_safe_up() which calls wake_up_process > > > outside of the spinlock. This isn

Re: [PATCH] RFC: console: hack up console_lock more v3

2019-05-09 Thread Daniel Vetter
On Thu, May 9, 2019 at 2:31 PM Peter Zijlstra wrote: > On Thu, May 09, 2019 at 02:09:03PM +0200, Daniel Vetter wrote: > > Fix this by creating a prinkt_safe_up() which calls wake_up_process > > outside of the spinlock. This isn't correct in full generality, but > > good enough for console_lock: >

Re: [PATCH] RFC: console: hack up console_lock more v3

2019-05-09 Thread Chris Wilson
Quoting Daniel Vetter (2019-05-09 13:09:03) > console_trylock, called from within printk, can be called from pretty > much anywhere. Including try_to_wake_up. Note that this isn't common, > usually the box is in pretty bad shape at that point already. But it > really doesn't help when then lockdep

Re: [PATCH] RFC: console: hack up console_lock more v3

2019-05-09 Thread Peter Zijlstra
On Thu, May 09, 2019 at 02:09:03PM +0200, Daniel Vetter wrote: > Fix this by creating a prinkt_safe_up() which calls wake_up_process > outside of the spinlock. This isn't correct in full generality, but > good enough for console_lock: > > - console_lock doesn't use interruptible or killable or tim