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authorTejun Heo <tj@kernel.org>2011-11-18 10:55:35 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2011-12-21 12:57:37 -0800
commit6400c8a382ded237df5dc1605f0d06e7939ff4da (patch)
treeb1c13ae760a87d9d758e0741ab0e418d8a870915 /mm/percpu-vm.c
parent5341e68f9b6c25c0a062de6d730034640988a605 (diff)
percpu: fix chunk range calculation
commit a855b84c3d8c73220d4d3cd392a7bee7c83de70e upstream. Percpu allocator recorded the cpus which map to the first and last units in pcpu_first/last_unit_cpu respectively and used them to determine the address range of a chunk - e.g. it assumed that the first unit has the lowest address in a chunk while the last unit has the highest address. This simply isn't true. Groups in a chunk can have arbitrary positive or negative offsets from the previous one and there is no guarantee that the first unit occupies the lowest offset while the last one the highest. Fix it by actually comparing unit offsets to determine cpus occupying the lowest and highest offsets. Also, rename pcu_first/last_unit_cpu to pcpu_low/high_unit_cpu to avoid confusion. The chunk address range is used to flush cache on vmalloc area map/unmap and decide whether a given address is in the first chunk by per_cpu_ptr_to_phys() and the bug was discovered by invalid per_cpu_ptr_to_phys() translation for crash_note. Kudos to Dave Young for tracking down the problem. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: WANG Cong <xiyou.wangcong@gmail.com> Reported-by: Dave Young <dyoung@redhat.com> Tested-by: Dave Young <dyoung@redhat.com> LKML-Reference: <4EC21F67.10905@redhat.com> Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'mm/percpu-vm.c')
-rw-r--r--mm/percpu-vm.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index ea534960a04b..bfad72466653 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -143,8 +143,8 @@ static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
int page_start, int page_end)
{
flush_cache_vunmap(
- pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
- pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
+ pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
+ pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
}
static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
@@ -206,8 +206,8 @@ static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
int page_start, int page_end)
{
flush_tlb_kernel_range(
- pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
- pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
+ pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
+ pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
}
static int __pcpu_map_pages(unsigned long addr, struct page **pages,
@@ -284,8 +284,8 @@ static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
int page_start, int page_end)
{
flush_cache_vmap(
- pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
- pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
+ pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
+ pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
}
/**