| Message ID | 20201124061720.86766-7-aik@ozlabs.ru (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | genirq/irqdomain: Add reference counting to IRQs | expand |
Hi Alexey,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linux/master]
[also build test ERROR on linus/master v5.10-rc5 next-20201123]
[cannot apply to tip/irq/core tip/x86/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Alexey-Kardashevskiy/genirq-irqdomain-Add-reference-counting-to-IRQs/20201124-142727
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 09162bc32c880a791c6c0668ce0745cf7958f576
config: alpha-randconfig-r013-20201124 (attached as .config)
compiler: alpha-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/50199be6fbdf9f1f27ff037a6bd6c602e57f7a5f
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Alexey-Kardashevskiy/genirq-irqdomain-Add-reference-counting-to-IRQs/20201124-142727
git checkout 50199be6fbdf9f1f27ff037a6bd6c602e57f7a5f
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=alpha
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
kernel/irq/irqdomain.c: In function 'irq_dispose_mapping':
>> kernel/irq/irqdomain.c:868:19: error: 'struct irq_desc' has no member named 'kobj'
868 | kobject_put(&desc->kobj);
| ^~
kernel/irq/irqdomain.c: In function 'irq_domain_free_irqs':
kernel/irq/irqdomain.c:1685:20: error: 'struct irq_desc' has no member named 'kobj'
1685 | kobject_put(&desc->kobj);
| ^~
kernel/irq/irqdomain.c: At top level:
kernel/irq/irqdomain.c:1907:13: warning: no previous prototype for 'irq_domain_debugfs_init' [-Wmissing-prototypes]
1907 | void __init irq_domain_debugfs_init(struct dentry *root)
| ^~~~~~~~~~~~~~~~~~~~~~~
vim +868 kernel/irq/irqdomain.c
859
860 /**
861 * irq_dispose_mapping() - Unmap an interrupt
862 * @virq: linux irq number of the interrupt to unmap
863 */
864 void irq_dispose_mapping(unsigned int virq)
865 {
866 struct irq_desc *desc = irq_to_desc(virq);
867
> 868 kobject_put(&desc->kobj);
869 }
870 EXPORT_SYMBOL_GPL(irq_dispose_mapping);
871
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Alexey, On Tue, Nov 24 2020 at 17:17, Alexey Kardashevskiy wrote: > This moves hierarchical domain's irqs cleanup into the kobject release > hook to make irq_domain_free_irqs() as simple as kobject_put. Truly simple: Simply broken in multiple ways. CONFIG_SPARSE_IRQ=n is now completely buggered. It does not even compile anymore. Running core code changes through a larger set of cross compilers is neither rocket science nor optional. For CONFIG_SPARSE_IRQ=y, see below. > @@ -1675,14 +1679,11 @@ void irq_domain_free_irqs(unsigned int virq, unsigned int nr_irqs) > "NULL pointer, cannot free irq\n")) > return; > > - mutex_lock(&irq_domain_mutex); > - for (i = 0; i < nr_irqs; i++) > - irq_domain_remove_irq(virq + i); > - irq_domain_free_irqs_hierarchy(data->domain, virq, nr_irqs); > - mutex_unlock(&irq_domain_mutex); > + for (i = 0; i < nr_irqs; i++) { > + struct irq_desc *desc = irq_to_desc(virq + i); > > - irq_domain_free_irq_data(virq, nr_irqs); > - irq_free_descs(virq, nr_irqs); > + kobject_put(&desc->kobj); So up to this point both irq_dispose_mapping() _and_ irq_domain_free_irqs() invoked irq_free_descs(). Let's look at the call chains: irq_domain_free_irqs() irq_free_descs() mutex_lock(&sparse_irq_lock); for (i...) free_desc(from + i) irq_remove_debugfs_entry(); unregister_irq_proc(); irq_sysfs_del(); delete_irq_desc(); call_rcu(); bitmap_clear(allocated_irqs, ...); mutex_unlock(&sparse_irq_lock); with your modifications it does: irq_domain_free_irqs() for (i...) kobject_put(&desc->kobj) irq_kobj_release() if (desc->free_irq) desc->free_irq(desc); irq_remove_debugfs_entry(); unregister_irq_proc(); delete_irq_desc(); call_rcu(); Can you spot the wreckage? It's not even subtle, it's more than obvious. 1) None of the operations in irq_kobj_release() is protected by sparse_irq_lock anymore. There was a comment in free_desc() which explained what is protected. You removed parts of that comment and just left the sysfs portion of it above delete_irq_desc() which is completely bogus because you removed the irq_sysfs_del() call. 2) Nothing removes the freed interrupts from the allocation bitmap. Run this often enough and you exhausted the interrupt space. And no, you cannot just go and invoke irq_free_descs() instead of kobject_put(), simply because you'd create lock order inversion vs. the free_irq() callback. So no, it's not that simple and I'm not at all interested in another respin of this with some more duct tape applied. It can be done, but that needs way more thought, a proper design which preserves the existing semantics completely and wants to be a fine grained series where each patch does exactly ONE small thing which is reviewable and testable on _ALL_ users of this code, i.e. _ALL_ architectures and irq chip implementations. Thanks, tglx
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 4779d912bb86..a0a81cc6c524 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -863,21 +863,9 @@ EXPORT_SYMBOL_GPL(irq_create_of_mapping); */ void irq_dispose_mapping(unsigned int virq) { - struct irq_data *irq_data = irq_get_irq_data(virq); - struct irq_domain *domain; + struct irq_desc *desc = irq_to_desc(virq); - if (!virq || !irq_data) - return; - - domain = irq_data->domain; - if (WARN_ON(domain == NULL)) - return; - - if (irq_domain_is_hierarchy(domain)) { - irq_domain_free_irqs(virq, 1); - } else { - irq_free_desc(virq); - } + kobject_put(&desc->kobj); } EXPORT_SYMBOL_GPL(irq_dispose_mapping); @@ -1396,6 +1384,19 @@ int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain, return domain->ops->alloc(domain, irq_base, nr_irqs, arg); } +static void irq_domain_hierarchy_free_desc(struct irq_desc *desc) +{ + unsigned int virq = desc->irq_data.irq; + struct irq_data *data = irq_get_irq_data(virq); + + mutex_lock(&irq_domain_mutex); + irq_domain_remove_irq(virq); + irq_domain_free_irqs_hierarchy(data->domain, virq, 1); + mutex_unlock(&irq_domain_mutex); + + irq_domain_free_irq_data(virq, 1); +} + int __irq_domain_alloc_irqs_data(struct irq_domain *domain, int virq, unsigned int nr_irqs, int node, void *arg, const struct irq_affinity_desc *affinity) @@ -1430,7 +1431,10 @@ int __irq_domain_alloc_irqs_data(struct irq_domain *domain, int virq, } for (i = 0; i < nr_irqs; i++) { + struct irq_desc *desc = irq_to_desc(virq + i); + irq_domain_insert_irq(virq + i); + desc->free_irq = irq_domain_hierarchy_free_desc; } mutex_unlock(&irq_domain_mutex); @@ -1675,14 +1679,11 @@ void irq_domain_free_irqs(unsigned int virq, unsigned int nr_irqs) "NULL pointer, cannot free irq\n")) return; - mutex_lock(&irq_domain_mutex); - for (i = 0; i < nr_irqs; i++) - irq_domain_remove_irq(virq + i); - irq_domain_free_irqs_hierarchy(data->domain, virq, nr_irqs); - mutex_unlock(&irq_domain_mutex); + for (i = 0; i < nr_irqs; i++) { + struct irq_desc *desc = irq_to_desc(virq + i); - irq_domain_free_irq_data(virq, nr_irqs); - irq_free_descs(virq, nr_irqs); + kobject_put(&desc->kobj); + } } /**
This moves hierarchical domain's irqs cleanup into the kobject release hook to make irq_domain_free_irqs() as simple as kobject_put. Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> --- kernel/irq/irqdomain.c | 43 +++++++++++++++++++++--------------------- 1 file changed, 22 insertions(+), 21 deletions(-)