Re: + proc-dont-lock-task_structs-indefinitely-cpuset-fix-2.patch added to -mm tree

[Andrew Morton <akpm@osdl.org>]

Paul Jackson <pj@sgi.com> wrote:
>
> Ok - down to the patch:
> 
>  1) gregkh-driver-empty_release_functions_are_broken.patch         - good
>  2) gregkh-driver-allow-sysfs-attribute-files-to-be-pollable.patch - special case
>  3) gregkh-driver-fix-up-the-sysfs-pollable-patch.patch            - bad
> 
>  Up through and including (1), it all seems fine.

OK, thanks.  So
gregkh-driver-allow-sysfs-attribute-files-to-be-pollable.patch is the
problem.   Odd.

<looks at sysfs_poll()>

If that gets called on a top-level file in /sys, won't
filp->f_dentry->d_parent be pointing at a non-sysfs dentry?

>  With (3) or more loaded, it fails to boot, with the crash
>  given before (and appended below for completeness).
> 
>  With patchs up through (2) loaded, it boots, but complains 27
>  times during the boot
> 
>  One of the 27 complaints for special case (2):
>  ================================= begin =================================
>  Debug: sleeping function called from invalid context at drivers/base/core.c:343^M
>  in_atomic():1, irqs_disabled():0^M
>  ^M
>  Call Trace:^M
>   [<a0000001000132c0>] show_stack+0x40/0xa0^M
>                                  sp=e00002bc3a49f9b0 bsp=e00002bc3a499558^M
>   [<a000000100013b50>] dump_stack+0x30/0x60^M
>                                  sp=e00002bc3a49fb80 bsp=e00002bc3a499540^M
>   [<a00000010008ff80>] __might_sleep+0x200/0x220^M
>                                  sp=e00002bc3a49fb80 bsp=e00002bc3a499510^M
>   [<a0000001004b58b0>] put_device+0x30/0x60^M
>                                  sp=e00002bc3a49fb90 bsp=e00002bc3a4994f0^M
>   [<a00000010051e470>] scsi_put_command+0x170/0x1a0^M
>                                  sp=e00002bc3a49fb90 bsp=e00002bc3a499498^M
>   [<a000000100528c80>] scsi_next_command+0x40/0x80^M
>                                  sp=e00002bc3a49fb90 bsp=e00002bc3a499468^M
>   [<a0000001005296a0>] scsi_end_request+0x1a0/0x1e0^M
>                                  sp=e00002bc3a49fb90 bsp=e00002bc3a499420^M
>   [<a000000100529a50>] scsi_io_completion+0x370/0x820^M
>                                  sp=e00002bc3a49fb90 bsp=e00002bc3a499388^M

Yeah, known problem - big messiness in scsi.  That's why -mm includes
revert-gregkh-driver-put_device-might_sleep.patch.  Looks like I need to
add revert-gregkh-driver-allow-sysfs-attribute-files-to-be-pollable.patch too ;)