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Nick Piggin 27d20fddc8 radix-tree: fix RCU bug ... Salman Qazi describes the following radix-tree bug: In the following case, we get can get a deadlock: 0. The radix tree contains two items, one has the index 0. 1. The reader (in this case find_get_pages) takes the rcu_read_lock. 2. The reader acquires slot(s) for item(s) including the index 0 item. 3. The non-zero index item is deleted, and as a consequence the other item is moved to the root of the tree. The place where it used to be is queued for deletion after the readers finish. 3b. The zero item is deleted, removing it from the direct slot, it remains in the rcu-delayed indirect node. 4. The reader looks at the index 0 slot, and finds that the page has 0 ref count 5. The reader looks at it again, hoping that the item will either be freed or the ref count will increase. This never happens, as the slot it is looking at will never be updated. Also, this slot can never be reclaimed because the reader is holding rcu_read_lock and is in an infinite loop. The fix is to re-use the same "indirect" pointer case that requires a slot lookup retry into a general "retry the lookup" bit. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Reported-by: Salman Qazi <sqazi@google.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2010-11-12 07:55:32 -08:00
..
Kconfig	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu	2010-10-22 17:31:36 -07:00
Kconfig.debug	…
Makefile	percpu: use percpu allocator on UP too	2010-10-02 10:26:05 +03:00
backing-dev.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6	2010-10-26 17:58:44 -07:00
bootmem.c	x86, memblock: Replace e820_/_early string with memblock_	2010-08-27 11:13:47 -07:00
bounce.c	bounce: call flush_dcache_page() after bounce_copy_vec()	2010-09-09 18:57:25 -07:00
compaction.c	mm: compaction: handle active and inactive fairly in too_many_isolated	2010-09-09 18:57:24 -07:00
debug-pagealloc.c	…
dmapool.c	mm: add a might_sleep_if() to dma_pool_alloc()	2010-10-26 16:52:08 -07:00
fadvise.c	readahead: introduce FMODE_RANDOM for POSIX_FADV_RANDOM	2010-03-06 11:26:25 -08:00
failslab.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
filemap.c	radix-tree: fix RCU bug	2010-11-12 07:55:32 -08:00
filemap_xip.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
fremap.c	Avoid pgoff overflow in remap_file_pages	2010-09-25 09:34:58 -07:00
highmem.c	mm,x86: fix kmap_atomic_push vs ioremap_32.c	2010-10-27 18:03:05 -07:00
hugetlb.c	mm/hugetlb.c: add missing spin_lock() to hugetlb_cow()	2010-10-26 16:52:11 -07:00
hwpoison-inject.c	HWPOISON, hugetlb: support hwpoison injection for hugepage	2010-08-11 09:23:11 +02:00
init-mm.c	mm: provide init_mm mm_context initializer	2010-08-09 20:44:54 -07:00
internal.h	mm: fix is_mem_section_removable() page_order BUG_ON check	2010-10-26 16:52:11 -07:00
kmemcheck.c	kmemcheck: Fix build errors due to missing slab.h	2010-03-30 22:02:32 +09:00
kmemleak-test.c	…
kmemleak.c	kmemleak: Fix typo in the comment	2010-08-08 21:57:23 +01:00
ksm.c	ksm: fix bad user data when swapping	2010-10-04 11:09:53 -07:00
maccess.c	MN10300: Save frame pointer in thread_info struct rather than global var	2010-10-27 17:29:01 +01:00
madvise.c	HWPOISON: Add a madvise() injector for soft page offlining	2009-12-16 12:20:00 +01:00
memblock.c	memblock: Annotate memblock functions with __init_memblock	2010-10-11 16:00:52 -07:00
memcontrol.c	memcg: null dereference on allocation failure	2010-11-12 07:55:31 -08:00
memory-failure.c	mm: compaction: fix COMPACTPAGEFAILED counting	2010-10-26 16:52:06 -07:00
memory.c	use clear_page()/copy_page() in favor of memset()/memcpy() on whole pages	2010-10-26 16:52:13 -07:00
memory_hotplug.c	mm: do_migrate_range: reduce list_empty() check	2010-10-26 16:52:11 -07:00
mempolicy.c	numa: fix slab_node(MPOL_BIND)	2010-10-28 10:04:30 -07:00
mempool.c	…
migrate.c	mm: fix error reporting in move_pages() syscall	2010-10-26 16:52:11 -07:00
mincore.c	mincore: do nested page table walks	2010-05-25 08:06:58 -07:00
mlock.c	mm: Move vma_stack_continue into mm.h	2010-09-09 09:05:06 -07:00
mm_init.c	…
mmap.c	audit mmap	2010-10-30 08:45:43 -04:00
mmu_context.c	exit: fix oops in sync_mm_rss	2010-03-24 16:31:21 -07:00
mmu_notifier.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
mmzone.c	mm: page allocator: calculate a better estimate of NR_FREE_PAGES when memory is low and kswapd is awake	2010-09-09 18:57:25 -07:00
mprotect.c	perf_events: Fix perf_counter_mmap() hook in mprotect()	2010-11-09 10:19:38 -08:00
mremap.c	mm: remove pte_*map_nested()	2010-10-26 16:52:08 -07:00
msync.c	sanitize vfs_fsync calling conventions	2010-05-21 18:31:21 -04:00
nommu.c	audit mmap	2010-10-30 08:45:43 -04:00
oom_kill.c	oom: kill all threads sharing oom killed task's mm	2010-10-26 16:52:05 -07:00
page-writeback.c	writeback: remove the internal 5% low bound on dirty_ratio	2010-10-26 16:52:08 -07:00
page_alloc.c	mm: add casts to/from gfp_t in gfp_to_alloc_flags()	2010-10-26 16:52:09 -07:00
page_cgroup.c	kmemleak: Annotate false positive in init_section_page_cgroup()	2010-07-19 11:54:14 +01:00
page_io.c	block: unify flags for struct bio and struct request	2010-08-07 18:20:39 +02:00
page_isolation.c	mm: page_isolation: codeclean fix comment and rm unneeded val init	2010-10-26 16:52:11 -07:00
pagewalk.c	pagemap: fix pfn calculation for hugepage	2010-04-07 08:38:04 -07:00
percpu-km.c	percpu: clear memory allocated with the km allocator	2010-10-02 10:28:42 +03:00
percpu-vm.c	percpu: move vmalloc based chunk management into percpu-vm.c	2010-05-01 08:30:50 +02:00
percpu.c	Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2010-10-24 13:41:39 -07:00
prio_tree.c	…
quicklist.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
readahead.c	readahead.c: fix comment	2010-05-25 08:07:00 -07:00
rmap.c	rmap: make anon_vma_chain_free() static	2010-10-26 16:52:10 -07:00
shmem.c	convert get_sb_nodev() users	2010-10-29 04:16:31 -04:00
slab.c	replace nested max/min macros with {max,min}3 macro	2010-10-26 16:52:12 -07:00
slob.c	slob: fix gfp flags for order-0 page allocations	2010-10-02 10:24:28 +03:00
slub.c	SLUB: Fix memory hotplug with !NUMA	2010-10-06 21:16:42 +03:00
sparse-vmemmap.c	x86: Use memblock to replace early_res	2010-08-27 11:12:29 -07:00
sparse.c	sparsemem: on no vmemmap path put mem_map on node high too	2010-05-25 08:06:56 -07:00
swap.c	fuse: use release_pages()	2010-10-27 18:03:17 -07:00
swap_state.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
swapfile.c	/proc/swaps: support polling	2010-10-26 16:52:11 -07:00
thrash.c	…
truncate.c	check ATTR_SIZE contraints in inode_change_ok	2010-08-09 16:47:39 -04:00
util.c	export __get_user_pages_fast() function	2010-10-24 10:51:24 +02:00
vmalloc.c	mm: add vzalloc() and vzalloc_node() helpers	2010-10-26 16:52:10 -07:00
vmscan.c	vmscan: avoid setting zone congested if no page dirty	2010-11-12 07:55:31 -08:00
vmstat.c	vmstat: fix offset calculation on void*	2010-11-03 14:39:58 -04:00