Re: please fix FUSION (Was: [v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-24 Thread Oleg Nesterov
On 03/22, James Bottomley wrote: OK, the fix from the SCSI point of view is to make the mpt teardown path actually work. The whole thing looks to be a complete mess because there's another place where it will do the wrong thing in mptscsih_remove(). You always have to call mpt_detach()

Re: please fix FUSION (Was:[v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-23 Thread Thomas Gleixner
On Sun, 23 Mar 2014, Tetsuo Handa wrote: Thomas Gleixner wrote: But then systemd/udev mutters: You migh be able to work around the timeout with udev rules and OPTIONS+=event_timeout=120, but that code was maybe never used or tested, so it might not work correctly. [1]

Re: please fix FUSION (Was:[v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-23 Thread James Bottomley
On Sun, 2014-03-23 at 09:04 +0100, Thomas Gleixner wrote: On Sun, 23 Mar 2014, Tetsuo Handa wrote: Thomas Gleixner wrote: But then systemd/udev mutters: You migh be able to work around the timeout with udev rules and OPTIONS+=event_timeout=120, but that code was maybe

Re: please fix FUSION (Was:[v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-23 Thread Thomas Gleixner
On Sun, 23 Mar 2014, James Bottomley wrote: On Sun, 2014-03-23 at 09:04 +0100, Thomas Gleixner wrote: On Sun, 23 Mar 2014, Tetsuo Handa wrote: Thomas Gleixner wrote: But then systemd/udev mutters: You migh be able to work around the timeout with udev rules and

Re: please fix FUSION (Was:[v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-23 Thread James Bottomley
On Sun, 2014-03-23 at 15:28 +0100, Thomas Gleixner wrote: On Sun, 23 Mar 2014, James Bottomley wrote: On Sun, 2014-03-23 at 09:04 +0100, Thomas Gleixner wrote: On Sun, 23 Mar 2014, Tetsuo Handa wrote: Thomas Gleixner wrote: But then systemd/udev mutters: You migh

Re: please fix FUSION (Was: [v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-22 Thread Tetsuo Handa
Oleg Nesterov wrote: Tetsuo, what do you think? I don't like blocking SIGKILL while doing operations that depend on memory allocation by other processes. If the OOM killer is triggered and it chose the process blocking SIGKILL in mptsas_init() (I know it unlikely happens), it generates the OOM

Re: please fix FUSION (Was: [v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-22 Thread Oleg Nesterov
On 03/22, Tetsuo Handa wrote: Oleg Nesterov wrote: Tetsuo, what do you think? I don't like blocking SIGKILL while doing operations that depend on memory allocation by other processes. If the OOM killer is triggered and it chose the process blocking SIGKILL in mptsas_init() (I know it

Re: please fix FUSION (Was: [v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-22 Thread James Bottomley
On Sat, 2014-03-22 at 20:25 +0100, Oleg Nesterov wrote: On 03/22, Tetsuo Handa wrote: Oleg Nesterov wrote: Tetsuo, what do you think? I don't like blocking SIGKILL while doing operations that depend on memory allocation by other processes. If the OOM killer is triggered and it chose

Re: please fix FUSION (Was: [v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-22 Thread Thomas Gleixner
On Sat, 22 Mar 2014, Oleg Nesterov wrote: On 03/22, Tetsuo Handa wrote: Many kernel operations (e.g. mutex_lock() wait_event() wait_for_completion()) ignore SIGKILL and the current users depend on SIGKILL being ignored. Thus, commit 786235ee sounds like a kernel API breakage.

Re: please fix FUSION (Was: [v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-22 Thread Thomas Gleixner
On Sat, 22 Mar 2014, Thomas Gleixner wrote: On Sat, 22 Mar 2014, Oleg Nesterov wrote: Personally I dislike this change. In fact I think it is ugly. But this is only my opinion. It's not only ugly, it's activly wrong. It's as wrong as 786235ee itself. And 786235ee needs to be reverted and

Re: please fix FUSION (Was:[v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-22 Thread Tetsuo Handa
Oleg Nesterov wrote: On 03/22, Tetsuo Handa wrote: Oleg Nesterov wrote: Tetsuo, what do you think? I don't like blocking SIGKILL while doing operations that depend on memory allocation by other processes. If the OOM killer is triggered and it chose the process blocking SIGKILL in

Re: please fix FUSION (Was:[v3.13][v3.14][Regression]kthread:makekthread_create()killable)

2014-03-22 Thread Tetsuo Handa
Thomas Gleixner wrote: But then systemd/udev mutters: You migh be able to work around the timeout with udev rules and OPTIONS+=event_timeout=120, but that code was maybe never used or tested, so it might not work correctly. [1] AFAICT from the ubuntu bug system [2] nobody

Re: please fix FUSION (Was: [v3.13][v3.14][Regression] kthread:makekthread_create()killable)

2014-03-21 Thread Oleg Nesterov
On 03/20, Oleg Nesterov wrote: On 03/20, Joseph Salisbury wrote: There was some testing done with your test kernel. The data collected while running your kernel is available in the bug report: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1276705/comments/58 Joseph, thanks a

Re: please fix FUSION (Was: [v3.13][v3.14][Regression] kthread:makekthread_create()killable)

2014-03-21 Thread Linus Torvalds
On Fri, Mar 21, 2014 at 11:34 AM, Oleg Nesterov o...@redhat.com wrote: Yes, it seems that it actually needs 30 secs. It spends most of the time (30.13286 seconds) in [..] So how about taking a completely different approach: - just say that waiting for devices in the module init sequence for

Re: please fix FUSION (Was: [v3.13][v3.14][Regression] kthread:makekthread_create()killable)

2014-03-21 Thread James Bottomley
On Fri, 2014-03-21 at 12:32 -0700, Linus Torvalds wrote: On Fri, Mar 21, 2014 at 11:34 AM, Oleg Nesterov o...@redhat.com wrote: Yes, it seems that it actually needs 30 secs. It spends most of the time (30.13286 seconds) in [..] So how about taking a completely different approach: -

Re: please fix FUSION (Was: [v3.13][v3.14][Regression] kthread:makekthread_create()killable)

2014-03-20 Thread Joseph Salisbury
On 03/19/2014 03:42 PM, Oleg Nesterov wrote: On 03/19, Oleg Nesterov wrote: On 03/19, Oleg Nesterov wrote: But please do not forget that the kernel crashes. Whatever else we do, this should be fixed anyway. And this should be fixed in driver. drivers/message/fusion/ is obviously buggy.

Re: please fix FUSION (Was: [v3.13][v3.14][Regression] kthread:makekthread_create()killable)

2014-03-20 Thread Oleg Nesterov
On 03/20, Joseph Salisbury wrote: On 03/19/2014 03:42 PM, Oleg Nesterov wrote: On 03/19, Oleg Nesterov wrote: On 03/19, Oleg Nesterov wrote: But please do not forget that the kernel crashes. Whatever else we do, this should be fixed anyway. And this should be fixed in driver.

please fix FUSION (Was: [v3.13][v3.14][Regression] kthread:makekthread_create()killable)

2014-03-19 Thread Oleg Nesterov
On 03/19, Oleg Nesterov wrote: But please do not forget that the kernel crashes. Whatever else we do, this should be fixed anyway. And this should be fixed in driver. drivers/message/fusion/ is obviously buggy. mptsas_probe() does sh = scsi_host_alloc(...); if

Re: please fix FUSION (Was: [v3.13][v3.14][Regression] kthread:makekthread_create()killable)

2014-03-19 Thread Oleg Nesterov
On 03/19, Oleg Nesterov wrote: On 03/19, Oleg Nesterov wrote: But please do not forget that the kernel crashes. Whatever else we do, this should be fixed anyway. And this should be fixed in driver. drivers/message/fusion/ is obviously buggy. Perhaps this is the only problem and Tetsuo

Re: please fix FUSION (Was: [v3.13][v3.14][Regression] kthread:makekthread_create()killable)

2014-03-19 Thread Joseph Salisbury
On 03/19/2014 03:42 PM, Oleg Nesterov wrote: On 03/19, Oleg Nesterov wrote: On 03/19, Oleg Nesterov wrote: But please do not forget that the kernel crashes. Whatever else we do, this should be fixed anyway. And this should be fixed in driver. drivers/message/fusion/ is obviously buggy.