Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-17 Thread Josh Poimboeuf
On Tue, Apr 17, 2018 at 05:37:46PM +0200, Petr Mladek wrote: > On Mon 2018-04-16 14:04:25, Josh Poimboeuf wrote: > > On Mon, Apr 16, 2018 at 04:58:11PM +0200, Petr Mladek wrote: > > > On Wed 2018-04-11 10:48:52, Josh Poimboeuf wrote: > > > > On Wed, Apr 11, 2018 at 04:17:11PM +0200, Petr Mladek

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-17 Thread Petr Mladek
On Mon 2018-04-16 14:04:25, Josh Poimboeuf wrote: > On Mon, Apr 16, 2018 at 04:58:11PM +0200, Petr Mladek wrote: > > On Wed 2018-04-11 10:48:52, Josh Poimboeuf wrote: > > > On Wed, Apr 11, 2018 at 04:17:11PM +0200, Petr Mladek wrote: > > > > Second, unrelated patches must never patch the same

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-17 Thread Miroslav Benes
> > > > Second, unrelated patches must never patch the same functions. > > > > Otherwise we would not be able to define which implementation > > > > should be used. This is especially important when a patch is > > > > removed and we need to fallback either to another patch or > > > > original

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-16 Thread Josh Poimboeuf
On Mon, Apr 16, 2018 at 04:58:11PM +0200, Petr Mladek wrote: > On Wed 2018-04-11 10:48:52, Josh Poimboeuf wrote: > > On Wed, Apr 11, 2018 at 04:17:11PM +0200, Petr Mladek wrote: > > > > I still agree with my original conclusion that enforcing stack order no > > > > longer makes sense though. > > >

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-16 Thread Petr Mladek
On Wed 2018-04-11 10:48:52, Josh Poimboeuf wrote: > On Wed, Apr 11, 2018 at 04:17:11PM +0200, Petr Mladek wrote: > > > I still agree with my original conclusion that enforcing stack order no > > > longer makes sense though. > > > > The question is what we will get if we remove the stack. Will it

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-11 Thread Josh Poimboeuf
On Wed, Apr 11, 2018 at 04:17:11PM +0200, Petr Mladek wrote: > > I still agree with my original conclusion that enforcing stack order no > > longer makes sense though. > > The question is what we will get if we remove the stack. Will it > really make the code easier and livepatching more safe? >

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-11 Thread Petr Mladek
On Wed 2018-04-11 07:32:14, Josh Poimboeuf wrote: > On Wed, Apr 11, 2018 at 10:07:31AM +0200, Miroslav Benes wrote: > > > > I was confused by wording "in the middle". It suggested that there > > > > might had been enabled patches on the top and the bottom of the stack > > > > and some disabled

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-11 Thread Miroslav Benes
On Wed, 11 Apr 2018, Josh Poimboeuf wrote: > On Wed, Apr 11, 2018 at 10:07:31AM +0200, Miroslav Benes wrote: > > > > I was confused by wording "in the middle". It suggested that there > > > > might had been enabled patches on the top and the bottom of the stack > > > > and some disabled patches

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-11 Thread Josh Poimboeuf
On Wed, Apr 11, 2018 at 10:07:31AM +0200, Miroslav Benes wrote: > > > I was confused by wording "in the middle". It suggested that there > > > might had been enabled patches on the top and the bottom of the stack > > > and some disabled patches in between at the same time (or vice versa). > > >

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-11 Thread Miroslav Benes
On Tue, 10 Apr 2018, Josh Poimboeuf wrote: > On Tue, Apr 10, 2018 at 10:34:55AM +0200, Petr Mladek wrote: > > > > > > > We were just recently discussing the possibility of not allowing > > > > > > > the > > > > > > > disabling of patches at all. If we're not going that far, let's > > > > > > >

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-11 Thread Miroslav Benes
On Tue, 10 Apr 2018, Josh Poimboeuf wrote: > > > I agree here. Practically we use only cumulative replacement patches at > > > SUSE. So with that in mind I don't care about the stacking much. But, it > > > may make sense for someone else. Evgenii mentioned they used it for > > > hotfixes.

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-10 Thread Josh Poimboeuf
> > I agree here. Practically we use only cumulative replacement patches at > > SUSE. So with that in mind I don't care about the stacking much. But, it > > may make sense for someone else. Evgenii mentioned they used it for > > hotfixes. Therefore I'm reluctant to remove it completely. > > Well,

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-10 Thread Josh Poimboeuf
On Tue, Apr 10, 2018 at 10:34:55AM +0200, Petr Mladek wrote: > > > > > > We were just recently discussing the possibility of not allowing the > > > > > > disabling of patches at all. If we're not going that far, let's at > > > > > > least further restrict it, for the sanity of our code, so we

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-10 Thread Evgenii Shatokhin
On 10.04.2018 16:21, Miroslav Benes wrote: I think you're missing my point. This isn't about your patch set, per se. It's really about our existing code. Today, our patch stack doesn't follow real stack semantics, because patches in the middle might be disabled. I see that as a problem.

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-10 Thread Miroslav Benes
> > > > I think you're missing my point. This isn't about your patch set, per > > > > se. It's really about our existing code. Today, our patch stack > > > > doesn't follow real stack semantics, because patches in the middle might > > > > be disabled. I see that as a problem. > > > > No,

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-10 Thread Petr Mladek
On Fri 2018-04-06 14:50:49, Josh Poimboeuf wrote: > On Mon, Mar 26, 2018 at 12:11:07PM +0200, Petr Mladek wrote: > > On Fri 2018-03-23 17:44:10, Josh Poimboeuf wrote: > > > On Fri, Mar 23, 2018 at 10:45:07AM +0100, Petr Mladek wrote: > > > > On Tue 2018-03-20 15:15:02, Josh Poimboeuf wrote: > > >

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-04-06 Thread Josh Poimboeuf
On Mon, Mar 26, 2018 at 12:11:07PM +0200, Petr Mladek wrote: > On Fri 2018-03-23 17:44:10, Josh Poimboeuf wrote: > > On Fri, Mar 23, 2018 at 10:45:07AM +0100, Petr Mladek wrote: > > > On Tue 2018-03-20 15:15:02, Josh Poimboeuf wrote: > > > > On Tue, Mar 20, 2018 at 01:25:38PM +0100, Petr Mladek

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-03-26 Thread Petr Mladek
On Fri 2018-03-23 17:44:10, Josh Poimboeuf wrote: > On Fri, Mar 23, 2018 at 10:45:07AM +0100, Petr Mladek wrote: > > On Tue 2018-03-20 15:15:02, Josh Poimboeuf wrote: > > > On Tue, Mar 20, 2018 at 01:25:38PM +0100, Petr Mladek wrote: > > > > On Mon 2018-03-19 16:43:24, Josh Poimboeuf wrote: > > >

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-03-23 Thread Josh Poimboeuf
On Fri, Mar 23, 2018 at 10:45:07AM +0100, Petr Mladek wrote: > On Tue 2018-03-20 15:15:02, Josh Poimboeuf wrote: > > On Tue, Mar 20, 2018 at 01:25:38PM +0100, Petr Mladek wrote: > > > On Mon 2018-03-19 16:43:24, Josh Poimboeuf wrote: > > > > On Mon, Mar 19, 2018 at 04:02:07PM +0100, Petr Mladek

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-03-23 Thread Petr Mladek
On Tue 2018-03-20 15:15:02, Josh Poimboeuf wrote: > On Tue, Mar 20, 2018 at 01:25:38PM +0100, Petr Mladek wrote: > > On Mon 2018-03-19 16:43:24, Josh Poimboeuf wrote: > > > On Mon, Mar 19, 2018 at 04:02:07PM +0100, Petr Mladek wrote: > > > > > Along those lines, I'd also propose that we constrain

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-03-20 Thread Josh Poimboeuf
On Tue, Mar 20, 2018 at 01:25:38PM +0100, Petr Mladek wrote: > On Mon 2018-03-19 16:43:24, Josh Poimboeuf wrote: > > On Mon, Mar 19, 2018 at 04:02:07PM +0100, Petr Mladek wrote: > > > > Can someone remind me why we're permanently disabling replaced patches? > > > > I seem to remember being

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-03-20 Thread Miroslav Benes
> > I don't know, does anybody really care about this case (patching on top > > of a disabled patch)? It just adds to the crazy matrix of possible > > scenarios we have to keep in our heads, which means more bugs, for very > > little (hypothetical) gain. > > It depends if the we remove the

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-03-20 Thread Evgenii Shatokhin
On 20.03.2018 15:25, Petr Mladek wrote: On Mon 2018-03-19 16:43:24, Josh Poimboeuf wrote: On Mon, Mar 19, 2018 at 04:02:07PM +0100, Petr Mladek wrote: Can someone remind me why we're permanently disabling replaced patches? I seem to remember being involved in that decision, but at least with

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-03-20 Thread Petr Mladek
On Mon 2018-03-19 16:43:24, Josh Poimboeuf wrote: > On Mon, Mar 19, 2018 at 04:02:07PM +0100, Petr Mladek wrote: > > > Can someone remind me why we're permanently disabling replaced patches? > > > I seem to remember being involved in that decision, but at least with > > > this latest version of

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-03-19 Thread Josh Poimboeuf
On Mon, Mar 19, 2018 at 04:02:07PM +0100, Petr Mladek wrote: > > Can someone remind me why we're permanently disabling replaced patches? > > I seem to remember being involved in that decision, but at least with > > this latest version of the patches, it seems like it would be simpler to > > just

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-03-19 Thread Petr Mladek
On Tue 2018-03-13 17:46:13, Josh Poimboeuf wrote: > On Wed, Mar 07, 2018 at 09:20:34AM +0100, Petr Mladek wrote: > > From: Jason Baron > > > > We are going to add a feature called atomic replace. It will allow to > > create a patch that would replace all already registered

Re: [PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-03-13 Thread Josh Poimboeuf
On Wed, Mar 07, 2018 at 09:20:34AM +0100, Petr Mladek wrote: > From: Jason Baron > > We are going to add a feature called atomic replace. It will allow to > create a patch that would replace all already registered patches. > > The replaced patches will stay registered because

[PATCH v10 05/10] livepatch: Support separate list for replaced patches.

2018-03-07 Thread Petr Mladek
From: Jason Baron We are going to add a feature called atomic replace. It will allow to create a patch that would replace all already registered patches. The replaced patches will stay registered because they are typically unregistered by some package uninstall scripts. But