[PATCH -stable 0/1] freezer: PF_FREEZER_NOSIG should be cleared along with PF_NOFREEZE

[PATCH -stable 0/1] freezer: PF_FREEZER_NOSIG should be cleared along with PF_NOFREEZE

[Oleg Nesterov]

On 12/06, Joseph Salisbury wrote:
>
> A couple of people have tested your patch and report if fixes the
> suspend/resume bug[0].

Great, thanks a lot.

> Will you be
> requesting this patch in the stable kernels?

I have to ;)

I tried to explain this in the changelog, but once again just in case...

This patch is only for -stable. It is only needed if a) b40a7959 was
backported and b) the kernel still has PF_FREEZER_NOSIG removed in 3.3.

Alernatively, b40a7959 can be reverted. But please note that this will
just hide the problem revealed by "incomplete" b40a7959.

Oleg.

Re: [PATCH -stable 1/1] freezer: PF_FREEZER_NOSIG should be cleared along with PF_NOFREEZE

[Oleg Nesterov]

This patch is only for pre-v3.3 stable trees which backported
b40a7959 "freezer: exec should clear PF_NOFREEZE along with PF_KTHREAD".
v3.3+ doesn't need this fix.

b40a7959 is the trivial bugfix, but unfortunately I forgot that
until 34b087e4 "freezer: kill unused set_freezable_with_signal()"
there were another only-for-kernel-threads flag, PF_FREEZER_NOSIG,
which should be cleared as well.

See https://bugs.launchpad.net/ubuntu/+source/v86d/+bug/1080530
The freezer fails because it expects that a PF_FREEZER_NOSIG task
doesn't need a signal. Before b40a7959 it wrongly succeeds leaving
the PF_NOFREEZE | PF_FREEZER_NOSIG task unfrozen.

Reported-and-tested-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Cc: stable@vger.kernel.org # pre v3.3 if commit b40a7959 was taken
Signed-off-by: Oleg Nesterov <oleg@redhat.com>

--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1084,7 +1084,7 @@ int flush_old_exec(struct linux_binprm *
 
 	set_fs(USER_DS);
 	current->flags &=
-		~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | PF_NOFREEZE);
+		~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | PF_NOFREEZE | PF_FREEZER_NOSIG);
 	flush_thread();
 	current->personality &= ~bprm->per_clear;
 

Re: [PATCH -stable 1/1] freezer: PF_FREEZER_NOSIG should be cleared along with PF_NOFREEZE

[Ben Hutchings]

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On Fri, 2012-12-07 at 15:49 +0100, Oleg Nesterov wrote:
> This patch is only for pre-v3.3 stable trees which backported
> b40a7959 "freezer: exec should clear PF_NOFREEZE along with PF_KTHREAD".
> v3.3+ doesn't need this fix.
[...]

Thanks very much, I've added this to the queue for 3.2.  However, in 3.2
PF_FORKNOEXEC is cleared by the binfmt code and not in fs/exec.c, and I
left that as it is.

Ben.

-- 
Ben Hutchings
It is impossible to make anything foolproof because fools are so ingenious.

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Re: [PATCH -stable 1/1] freezer: PF_FREEZER_NOSIG should be cleared along with PF_NOFREEZE

[Greg Kroah-Hartman]

On Fri, Dec 07, 2012 at 03:49:22PM +0100, Oleg Nesterov wrote:
> This patch is only for pre-v3.3 stable trees which backported
> b40a7959 "freezer: exec should clear PF_NOFREEZE along with PF_KTHREAD".
> v3.3+ doesn't need this fix.
> 
> b40a7959 is the trivial bugfix, but unfortunately I forgot that
> until 34b087e4 "freezer: kill unused set_freezable_with_signal()"
> there were another only-for-kernel-threads flag, PF_FREEZER_NOSIG,
> which should be cleared as well.
> 
> See https://bugs.launchpad.net/ubuntu/+source/v86d/+bug/1080530
> The freezer fails because it expects that a PF_FREEZER_NOSIG task
> doesn't need a signal. Before b40a7959 it wrongly succeeds leaving
> the PF_NOFREEZE | PF_FREEZER_NOSIG task unfrozen.
> 
> Reported-and-tested-by: Joseph Salisbury <joseph.salisbury@canonical.com>
> Cc: stable@vger.kernel.org # pre v3.3 if commit b40a7959 was taken

>From what I can tell, 3.0-stable didn't take this patch, so it should be
fine.  Ben, I don't know about 3.2, you should check this.

Oleg, thanks for doing this work, much appreciated.

greg k-h