Revision 1a3f2fd7fc4e8f24510830e265de2ffb8e3300d2 authored by Lu Baolu on 27 September 2020, 06:24:28 UTC, committed by Joerg Roedel on 01 October 2020, 12:54:17 UTC
Lock(&iommu->lock) without disabling irq causes lockdep warnings. [ 12.703950] ======================================================== [ 12.703962] WARNING: possible irq lock inversion dependency detected [ 12.703975] 5.9.0-rc6+ #659 Not tainted [ 12.703983] -------------------------------------------------------- [ 12.703995] systemd-udevd/284 just changed the state of lock: [ 12.704007] ffffffffbd6ff4d8 (device_domain_lock){..-.}-{2:2}, at: iommu_flush_dev_iotlb.part.57+0x2e/0x90 [ 12.704031] but this lock took another, SOFTIRQ-unsafe lock in the past: [ 12.704043] (&iommu->lock){+.+.}-{2:2} [ 12.704045] and interrupts could create inverse lock ordering between them. [ 12.704073] other info that might help us debug this: [ 12.704085] Possible interrupt unsafe locking scenario: [ 12.704097] CPU0 CPU1 [ 12.704106] ---- ---- [ 12.704115] lock(&iommu->lock); [ 12.704123] local_irq_disable(); [ 12.704134] lock(device_domain_lock); [ 12.704146] lock(&iommu->lock); [ 12.704158] <Interrupt> [ 12.704164] lock(device_domain_lock); [ 12.704174] *** DEADLOCK *** Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Link: https://lore.kernel.org/r/20200927062428.13713-1-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
1 parent 0bbe4ce
percpu-km.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* mm/percpu-km.c - kernel memory based chunk allocation
*
* Copyright (C) 2010 SUSE Linux Products GmbH
* Copyright (C) 2010 Tejun Heo <tj@kernel.org>
*
* Chunks are allocated as a contiguous kernel memory using gfp
* allocation. This is to be used on nommu architectures.
*
* To use percpu-km,
*
* - define CONFIG_NEED_PER_CPU_KM from the arch Kconfig.
*
* - CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK must not be defined. It's
* not compatible with PER_CPU_KM. EMBED_FIRST_CHUNK should work
* fine.
*
* - NUMA is not supported. When setting up the first chunk,
* @cpu_distance_fn should be NULL or report all CPUs to be nearer
* than or at LOCAL_DISTANCE.
*
* - It's best if the chunk size is power of two multiple of
* PAGE_SIZE. Because each chunk is allocated as a contiguous
* kernel memory block using alloc_pages(), memory will be wasted if
* chunk size is not aligned. percpu-km code will whine about it.
*/
#if defined(CONFIG_SMP) && defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
#error "contiguous percpu allocation is incompatible with paged first chunk"
#endif
#include <linux/log2.h>
static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
int page_start, int page_end, gfp_t gfp)
{
return 0;
}
static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
int page_start, int page_end)
{
/* nada */
}
static struct pcpu_chunk *pcpu_create_chunk(enum pcpu_chunk_type type,
gfp_t gfp)
{
const int nr_pages = pcpu_group_sizes[0] >> PAGE_SHIFT;
struct pcpu_chunk *chunk;
struct page *pages;
unsigned long flags;
int i;
chunk = pcpu_alloc_chunk(type, gfp);
if (!chunk)
return NULL;
pages = alloc_pages(gfp, order_base_2(nr_pages));
if (!pages) {
pcpu_free_chunk(chunk);
return NULL;
}
for (i = 0; i < nr_pages; i++)
pcpu_set_page_chunk(nth_page(pages, i), chunk);
chunk->data = pages;
chunk->base_addr = page_address(pages);
spin_lock_irqsave(&pcpu_lock, flags);
pcpu_chunk_populated(chunk, 0, nr_pages);
spin_unlock_irqrestore(&pcpu_lock, flags);
pcpu_stats_chunk_alloc();
trace_percpu_create_chunk(chunk->base_addr);
return chunk;
}
static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
{
const int nr_pages = pcpu_group_sizes[0] >> PAGE_SHIFT;
if (!chunk)
return;
pcpu_stats_chunk_dealloc();
trace_percpu_destroy_chunk(chunk->base_addr);
if (chunk->data)
__free_pages(chunk->data, order_base_2(nr_pages));
pcpu_free_chunk(chunk);
}
static struct page *pcpu_addr_to_page(void *addr)
{
return virt_to_page(addr);
}
static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai)
{
size_t nr_pages, alloc_pages;
/* all units must be in a single group */
if (ai->nr_groups != 1) {
pr_crit("can't handle more than one group\n");
return -EINVAL;
}
nr_pages = (ai->groups[0].nr_units * ai->unit_size) >> PAGE_SHIFT;
alloc_pages = roundup_pow_of_two(nr_pages);
if (alloc_pages > nr_pages)
pr_warn("wasting %zu pages per chunk\n",
alloc_pages - nr_pages);
return 0;
}
Computing file changes ...