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01c2965f07
linux/mm
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Sebastian Andrzej Siewior 01c2965f07 mm: dmapool: add/remove sysfs file outside of the pool lock lock 
cat /sys/.../pools followed by removal the device leads to:

|======================================================
|[ INFO: possible circular locking dependency detected ]
|3.17.0-rc4+ #1498 Not tainted
|-------------------------------------------------------
|rmmod/2505 is trying to acquire lock:
| (s_active#28){++++.+}, at: [<c017f754>] kernfs_remove_by_name_ns+0x3c/0x88
|
|but task is already holding lock:
| (pools_lock){+.+.+.}, at: [<c011494c>] dma_pool_destroy+0x18/0x17c
|
|which lock already depends on the new lock.
|the existing dependency chain (in reverse order) is:
|
|-> #1 (pools_lock){+.+.+.}:
|   [<c0114ae8>] show_pools+0x30/0xf8
|   [<c0313210>] dev_attr_show+0x1c/0x48
|   [<c0180e84>] sysfs_kf_seq_show+0x88/0x10c
|   [<c017f960>] kernfs_seq_show+0x24/0x28
|   [<c013efc4>] seq_read+0x1b8/0x480
|   [<c011e820>] vfs_read+0x8c/0x148
|   [<c011ea10>] SyS_read+0x40/0x8c
|   [<c000e960>] ret_fast_syscall+0x0/0x48
|
|-> #0 (s_active#28){++++.+}:
|   [<c017e9ac>] __kernfs_remove+0x258/0x2ec
|   [<c017f754>] kernfs_remove_by_name_ns+0x3c/0x88
|   [<c0114a7c>] dma_pool_destroy+0x148/0x17c
|   [<c03ad288>] hcd_buffer_destroy+0x20/0x34
|   [<c03a4780>] usb_remove_hcd+0x110/0x1a4

The problem is the lock order of pools_lock and kernfs_mutex in
dma_pool_destroy() vs show_pools() call path.

This patch breaks out the creation of the sysfs file outside of the
pools_lock mutex.  The newly added pools_reg_lock ensures that there is no
race of create vs destroy code path in terms whether or not the sysfs file
has to be deleted (and was it deleted before we try to create a new one)
and what to do if device_create_file() failed.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:59 -04:00
..
backing-dev.c mm: clean up zone flags 2014-10-09 22:25:57 -04:00
balloon_compaction.c mm: print more details for bad_page() 2014-01-23 16:36:50 -08:00
bootmem.c mm/bootmem.c: remove unused local `map' 2013-11-13 12:09:09 +09:00
cleancache.c mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE 2014-01-23 16:36:50 -08:00
cma.c mm: cma: adjust address limit to avoid hitting low/high memory boundary 2014-10-09 22:25:53 -04:00
compaction.c mm/compaction.c: fix warning of 'flags' may be used uninitialized 2014-10-09 22:25:57 -04:00
debug-pagealloc.c
debug.c mm/debug.c: use pr_emerg() 2014-10-09 22:25:59 -04:00
dmapool.c mm: dmapool: add/remove sysfs file outside of the pool lock lock 2014-10-09 22:25:59 -04:00
early_ioremap.c mm: create generic early_ioremap() support 2014-04-07 16:36:15 -07:00
fadvise.c teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long 2013-03-03 22:46:22 -05:00
failslab.c
filemap_xip.c seqcount: Add lockdep functionality to seqcount/seqlock structures 2013-11-06 12:40:26 +01:00
filemap.c NFS client updates for Linux 3.18 2014-10-08 12:49:23 -04:00
fremap.c mm: mark remap_file_pages() syscall as deprecated 2014-06-06 16:08:17 -07:00
frontswap.c swap: change swap_list_head to plist, add swap_avail_head 2014-06-04 16:54:07 -07:00
gup.c kvm: Faults which trigger IO release the mmap_sem 2014-09-24 14:07:54 +02:00
highmem.c mm/highmem: make kmap cache coloring aware 2014-08-06 18:01:22 -07:00
huge_memory.c mm: use VM_BUG_ON_MM where possible 2014-10-09 22:25:58 -04:00
hugetlb_cgroup.c hugetlb_cgroup: use lockdep_assert_held rather than spin_is_locked 2014-08-29 16:28:16 -07:00
hugetlb.c mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMA 2014-10-09 22:25:57 -04:00
hwpoison-inject.c mm/hwpoison-inject.c: remove unnecessary null test before debugfs_remove_recursive 2014-08-06 18:01:19 -07:00
init-mm.c
internal.h mm, compaction: pass gfp mask to compact_control 2014-10-09 22:25:55 -04:00
interval_tree.c mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMA 2014-10-09 22:25:57 -04:00
iov_iter.c fuse: honour max_read and max_write in direct_io mode 2014-09-26 21:16:51 -04:00
Kconfig mm/zpool: update zswap to use zpool 2014-08-06 18:01:23 -07:00
Kconfig.debug
kmemcheck.c mm/slab_common: move kmem_cache definition to internal header 2014-10-09 22:25:50 -04:00
kmemleak-test.c mm/kmemleak-test.c: use pr_fmt for logging 2014-06-06 16:08:18 -07:00
kmemleak.c mm: introduce kmemleak_update_trace() 2014-06-06 16:08:17 -07:00
ksm.c sched: Remove proliferation of wait_on_bit() action functions 2014-07-16 15:10:39 +02:00
list_lru.c mm: keep page cache radix tree nodes in check 2014-04-03 16:21:01 -07:00
maccess.c
madvise.c mm: update the description for madvise_remove 2014-08-06 18:01:18 -07:00
Makefile mm: move debug code out of page_alloc.c 2014-10-09 22:25:58 -04:00
memblock.c mem-hotplug: let memblock skip the hotpluggable memory regions in __next_mem_range() 2014-09-10 15:42:12 -07:00
memcontrol.c memcg: move memcg_update_cache_size() to slab_common.c 2014-10-09 22:25:59 -04:00
memory_hotplug.c memory-hotplug: add sysfs valid_zones attribute 2014-10-09 22:25:52 -04:00
memory-failure.c hwpoison: fix race with changing page during offlining 2014-08-06 18:01:19 -07:00
memory.c mm: softdirty: keep bit when zapping file pte 2014-09-26 08:10:35 -07:00
mempolicy.c mempolicy: unexport get_vma_policy() and remove its "task" arg 2014-10-09 22:25:56 -04:00
mempool.c mm/mempool.c: update the kmemleak stack trace for mempool allocations 2014-06-06 16:08:17 -07:00
migrate.c mm: migrate: Close race between migration completion and mprotect 2014-10-02 11:57:18 -07:00
mincore.c mm + fs: prepare for non-page entries in page cache radix trees 2014-04-03 16:21:00 -07:00
mlock.c mm: use VM_BUG_ON_MM where possible 2014-10-09 22:25:58 -04:00
mm_init.c mm: bring back /sys/kernel/mm 2014-01-27 21:02:39 -08:00
mmap.c mm: use VM_BUG_ON_MM where possible 2014-10-09 22:25:58 -04:00
mmu_context.c sched/mm: call finish_arch_post_lock_switch in idle_task_exit and use_mm 2014-02-21 08:50:17 +01:00
mmu_notifier.c kvm: Fix page ageing bugs 2014-09-24 14:07:58 +02:00
mmzone.c mm: numa: Change page last {nid,pid} into {cpu,pid} 2013-10-09 14:47:45 +02:00
mprotect.c mm: move mmu notifier call from change_protection to change_pmd_range 2014-04-07 16:35:50 -07:00
mremap.c mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMA 2014-10-09 22:25:57 -04:00
msync.c msync: fix incorrect fstart calculation 2014-07-03 09:21:53 -07:00
nobootmem.c mem-hotplug: let memblock skip the hotpluggable memory regions in __next_mem_range() 2014-09-10 15:42:12 -07:00
nommu.c arm64,ia64,ppc,s390,sh,tile,um,x86,mm: remove default gate area 2014-08-08 15:57:27 -07:00
oom_kill.c mm: clean up zone flags 2014-10-09 22:25:57 -04:00
page_alloc.c mm: move debug code out of page_alloc.c 2014-10-09 22:25:58 -04:00
page_cgroup.c mm/page_cgroup.c: mark functions as static 2014-04-03 16:21:02 -07:00
page_io.c fix __swap_writepage() compile failure on old gcc versions 2014-06-14 19:30:48 -05:00
page_isolation.c mm: memory-hotplug: enable memory hotplug to handle hugepage 2013-09-11 15:57:48 -07:00
page-writeback.c mm/page-writeback.c: use min3/max3 macros to avoid shadow warnings 2014-10-09 22:25:57 -04:00
pagewalk.c mm: use VM_BUG_ON_MM where possible 2014-10-09 22:25:58 -04:00
percpu-km.c
percpu-vm.c percpu: perform tlb flush after pcpu_map_pages() failure 2014-08-15 16:06:10 -04:00
percpu.c percpu: free percpu allocation info for uniprocessor system 2014-08-16 08:59:02 -04:00
pgtable-generic.c mm: actually clear pmd_numa before invalidating 2014-08-29 16:28:15 -07:00
process_vm_access.c start adding the tag to iov_iter 2014-05-06 17:32:49 -04:00
quicklist.c
readahead.c mm/readahead.c: remove unused file_ra_state from count_history_pages 2014-08-06 18:01:15 -07:00
rmap.c mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMA 2014-10-09 22:25:57 -04:00
shmem.c include/linux/migrate.h: remove migrate_page #define 2014-10-09 22:25:56 -04:00
slab_common.c memcg: move memcg_update_cache_size() to slab_common.c 2014-10-09 22:25:59 -04:00
slab.c mm/slab.c: use __seq_open_private() instead of seq_open() 2014-10-09 22:25:57 -04:00
slab.h mm/slab: use percpu allocator for cpu cache 2014-10-09 22:25:51 -04:00
slob.c mm/sl[ao]b: always track caller in kmalloc_(node_)track_caller() 2014-10-09 22:25:50 -04:00
slub.c mm/slab_common: commonize slab merge logic 2014-10-09 22:25:51 -04:00
sparse-vmemmap.c mm/sparse: use memblock apis for early memory allocations 2014-01-21 16:19:47 -08:00
sparse.c mm: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:35:54 -07:00
swap_state.c include/linux/migrate.h: remove migrate_page #define 2014-10-09 22:25:56 -04:00
swap.c mm: memcontrol: use page lists for uncharge batching 2014-08-08 15:57:18 -07:00
swapfile.c mm: memcontrol: rewrite uncharge API 2014-08-08 15:57:17 -07:00
truncate.c mm: memcontrol: rewrite uncharge API 2014-08-08 15:57:17 -07:00
util.c proc/maps: make vm_is_stack() logic namespace-friendly 2014-10-09 22:25:50 -04:00
vmacache.c mm,vmacache: optimize overflow system-wide flushing 2014-06-04 16:53:57 -07:00
vmalloc.c mm/vmalloc.c: use seq_open_private() instead of seq_open() 2014-10-09 22:25:56 -04:00
vmpressure.c arm, pm, vmpressure: add missing slab.h includes 2014-02-03 13:24:01 -05:00
vmscan.c mm: clean up zone flags 2014-10-09 22:25:57 -04:00
vmstat.c mm: vmscan: only update per-cpu thresholds for online CPU 2014-08-06 18:01:20 -07:00
workingset.c mm: keep page cache radix tree nodes in check 2014-04-03 16:21:01 -07:00
zbud.c mm/zpool: use prefixed module loading 2014-08-29 16:28:16 -07:00
zpool.c mm/zpool: use prefixed module loading 2014-08-29 16:28:16 -07:00
zsmalloc.c mm/zpool: use prefixed module loading 2014-08-29 16:28:16 -07:00
zswap.c mm/zswap.c: add __init to zswap_entry_cache_destroy() 2014-08-08 15:57:18 -07:00