Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1685351
| From | Sebastian Reichel <sebastian.reichel@collabora.co.uk> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [GIT pull] irq updates for 4.13 |
| Date | 2017-07-11 23:40 +0200 |
| Message-ID | <u2b2V-7At-1@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <u25Ae-48y-3@gated-at.bofh.it> <u26cV-4Ed-17@gated-at.bofh.it> <u26mC-4Hp-27@gated-at.bofh.it> <u27C2-5m0-17@gated-at.bofh.it> <u27Vn-5Hk-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
[Multipart message — attachments visible in raw view] - view raw
Hi,
On Tue, Jul 11, 2017 at 11:16:03AM -0700, Linus Torvalds wrote:
> On Tue, Jul 11, 2017 at 10:52 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> > Not completely, because of the free path issues. See the other mail. Tony
> > confirmed that it works. I wait for Sebastian and queue it with a proper
> > changelog, ok?
>
> Ugh, I absolutely detest your ugly "bool buslock" parameter to
> irq_release_resources().
So /me will skip testing Thomas' patch for now.
> And there seems to be no reason for it.
>
> Why don't you just move the
>
> chip_bus_sync_unlock(desc);
>
> call in __free_irq() down to just before you release the request_mutex?
>
> In fact, looking at __free_irq(), I note that it's locking is
> completely broken shit. Look at the
>
> if (!action) {
> WARN(1, "Trying to free already-free IRQ %d\n", irq);
>
> error case, and look for where it unlocks request_mutex. Yeah, it doesn't.
>
> So honestly, I think this code is broken, and it's broken partly
> because it has some really bad locking and logic rules.
>
> Why not fix those stupid bugs and clean things up at the same time?
> Make the rule be that as you take the request_mutex lock, you then
> also do the chip_bus_lock().
>
> And when you release the request_mutex lock, you do
> chip_bus_sync_unlock() just before.
>
> And no, I have no idea what the locking rules are for
> irq_finalize_oneshot() - it does that chip_bus_lock() without having
> any external serialization. Is that ok? Are the chip handlers able to
> deal with that? Same seems to go for free_percpu_irq().
>
> Anyway, patch attached (AGAIN, TOTALLY UNTESTED) showing what I mean,
> and fixing (well, modulo any bugs I introduced by my untested sh*t)
> that definite bug in lack of unlocking.
>
> But that "bool buslock" thing really is too disgusting. Conditional
> locking should not be done. It's a sign of serious problems, imnsho.
>
> Comments? Even if they are "Linus, you're way out of line, and you
> can't just move that chip_bus_sync_unlock() down like that because of
> XYZ, you moron".
>
> For example, it's entirely possible that we can't do the
> "synchronize_irq()" waiting while we hold that chip_bus_lock(). But
> the ones I looked at seemed to all take sleeping locks (or no locks at
> all - doing other things), which implies that they certainly can't be
> blocking irq delivery.
>
> So I'm *not* claiming that the attached patch is necessarily right. I
> just really don't like your conditional lock thing, and this would
> seem to possibly be a clean way around it if it works.
This fixes boot on Droid 4:
Tested-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
-- Sebastian
> kernel/irq/manage.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
> index 5624b2dd6b58..c4cbda784ea5 100644
> --- a/kernel/irq/manage.c
> +++ b/kernel/irq/manage.c
> @@ -1168,17 +1168,17 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
> new->flags &= ~IRQF_ONESHOT;
>
> mutex_lock(&desc->request_mutex);
> + chip_bus_lock(desc);
> +
> if (!desc->action) {
> ret = irq_request_resources(desc);
> if (ret) {
> pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
> new->name, irq, desc->irq_data.chip->name);
> - goto out_mutex;
> + goto out_unlock_chip_bus;
> }
> }
>
> - chip_bus_lock(desc);
> -
> /*
> * The following block of code has to be executed atomically
> */
> @@ -1385,12 +1385,11 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
> out_unlock:
> raw_spin_unlock_irqrestore(&desc->lock, flags);
>
> - chip_bus_sync_unlock(desc);
> -
> if (!desc->action)
> irq_release_resources(desc);
>
> -out_mutex:
> +out_unlock_chip_bus:
> + chip_bus_sync_unlock(desc);
> mutex_unlock(&desc->request_mutex);
>
> out_thread:
> @@ -1472,6 +1471,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
> WARN(1, "Trying to free already-free IRQ %d\n", irq);
> raw_spin_unlock_irqrestore(&desc->lock, flags);
> chip_bus_sync_unlock(desc);
> + mutex_unlock(&desc->request_mutex);
> return NULL;
> }
>
> @@ -1498,7 +1498,6 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
> #endif
>
> raw_spin_unlock_irqrestore(&desc->lock, flags);
> - chip_bus_sync_unlock(desc);
>
> unregister_handler_proc(irq, action);
>
> @@ -1535,6 +1534,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
> irq_remove_timings(desc);
> }
>
> + chip_bus_sync_unlock(desc);
> mutex_unlock(&desc->request_mutex);
>
> irq_chip_pm_put(&desc->irq_data);
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@linutronix.de> - 2017-07-09 11:00 +0200
Re: [GIT pull] irq updates for 4.13 Sebastian Reichel <sebastian.reichel@collabora.co.uk> - 2017-07-10 15:40 +0200
Re: [GIT pull] irq updates for 4.13 Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-10 19:10 +0200
Re: [GIT pull] irq updates for 4.13 Pavel Machek <pavel@ucw.cz> - 2017-07-10 21:40 +0200
Re: [GIT pull] irq updates for 4.13 Sebastian Reichel <sebastian.reichel@collabora.co.uk> - 2017-07-10 22:20 +0200
Re: [GIT pull] irq updates for 4.13 Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-10 23:30 +0200
Re: [GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@linutronix.de> - 2017-07-11 09:00 +0200
Re: [GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@linutronix.de> - 2017-07-11 11:50 +0200
Re: [GIT pull] irq updates for 4.13 Tony Lindgren <tony@atomide.com> - 2017-07-11 16:00 +0200
Re: [GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@linutronix.de> - 2017-07-11 16:50 +0200
Re: [GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@linutronix.de> - 2017-07-11 17:10 +0200
Re: [GIT pull] irq updates for 4.13 Tony Lindgren <tony@atomide.com> - 2017-07-11 17:50 +0200
Re: [GIT pull] irq updates for 4.13 Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-11 17:50 +0200
Re: [GIT pull] irq updates for 4.13 Sebastian Reichel <sebastian.reichel@collabora.co.uk> - 2017-07-11 18:20 +0200
Re: [GIT pull] irq updates for 4.13 Tony Lindgren <tony@atomide.com> - 2017-07-11 18:20 +0200
Re: [GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@linutronix.de> - 2017-07-11 19:20 +0200
Re: [GIT pull] irq updates for 4.13 Tony Lindgren <tony@atomide.com> - 2017-07-11 19:40 +0200
Re: [GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@linutronix.de> - 2017-07-11 18:30 +0200
Re: [GIT pull] irq updates for 4.13 Tony Lindgren <tony@atomide.com> - 2017-07-11 18:40 +0200
Re: [GIT pull] irq updates for 4.13 Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-11 18:40 +0200
Re: [GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@linutronix.de> - 2017-07-11 20:00 +0200
Re: [GIT pull] irq updates for 4.13 Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-11 20:20 +0200
Re: [GIT pull] irq updates for 4.13 Sebastian Reichel <sebastian.reichel@collabora.co.uk> - 2017-07-11 23:40 +0200
Re: [GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@tglx.de> - 2017-07-12 00:10 +0200
Re: [GIT pull] irq updates for 4.13 Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-12 00:10 +0200
Re: [GIT pull] irq updates for 4.13 Sebastian Reichel <sebastian.reichel@collabora.co.uk> - 2017-07-12 01:00 +0200
Re: [GIT pull] irq updates for 4.13 Tony Lindgren <tony@atomide.com> - 2017-07-12 07:30 +0200
Re: [GIT pull] irq updates for 4.13 Pavel Machek <pavel@ucw.cz> - 2017-07-15 22:30 +0200
Re: [GIT pull] irq updates for 4.13 Tony Lindgren <tony@atomide.com> - 2017-07-17 08:30 +0200
Re: [GIT pull] irq updates for 4.13 Linus Torvalds <torvalds@linux-foundation.org> - 2017-07-17 22:10 +0200
Re: [GIT pull] irq updates for 4.13 Pavel Machek <pavel@ucw.cz> - 2017-07-17 23:40 +0200
Re: [GIT pull] irq updates for 4.13 Grygorii Strashko <grygorii.strashko@ti.com> - 2017-07-11 17:50 +0200
Re: [GIT pull] irq updates for 4.13 Tony Lindgren <tony@atomide.com> - 2017-07-11 18:20 +0200
Re: [GIT pull] irq updates for 4.13 Geert Uytterhoeven <geert@linux-m68k.org> - 2017-07-12 10:10 +0200
Re: [GIT pull] irq updates for 4.13 Sebastian Reichel <sebastian.reichel@collabora.co.uk> - 2017-07-11 16:50 +0200
Re: [GIT pull] irq updates for 4.13 Tony Lindgren <tony@atomide.com> - 2017-07-11 18:30 +0200
Re: [GIT pull] irq updates for 4.13 Sebastian Reichel <sebastian.reichel@collabora.co.uk> - 2017-07-11 18:40 +0200
Re: [GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@linutronix.de> - 2017-07-11 12:00 +0200
Re: [GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@linutronix.de> - 2017-07-11 13:00 +0200
Re: [GIT pull] irq updates for 4.13 Sebastian Reichel <sebastian.reichel@collabora.co.uk> - 2017-07-11 13:30 +0200
Re: [GIT pull] irq updates for 4.13 Thomas Gleixner <tglx@linutronix.de> - 2017-07-11 15:30 +0200
Re: [GIT pull] irq updates for 4.13 Marc Zyngier <marc.zyngier@arm.com> - 2017-07-11 16:00 +0200
Re: [GIT pull] irq updates for 4.13 Sebastian Reichel <sebastian.reichel@collabora.co.uk> - 2017-07-11 16:50 +0200
csiph-web