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authoryalin wang <yalin.wang2010@gmail.com>2016-01-21 16:40:30 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-21 17:20:51 -0800
commit16fd0fe4aa92d0d621ecfe21de86f7fdcfa41947 (patch)
treed94d862bb32b160dcacb5467c099f52748f5f1dd
parent7162a1e87b3e380133dadc7909081bb70d0a7041 (diff)
mm: fix kernel crash in khugepaged thread
This crash is caused by NULL pointer deference, in page_to_pfn() marco, when page == NULL : Unable to handle kernel NULL pointer dereference at virtual address 00000000 Internal error: Oops: 94000006 [#1] SMP Modules linked in: CPU: 1 PID: 26 Comm: khugepaged Tainted: G W 4.3.0-rc6-next-20151022ajb-00001-g32f3386-dirty #3 PC is at khugepaged+0x378/0x1af8 LR is at khugepaged+0x418/0x1af8 Process khugepaged (pid: 26, stack limit = 0xffffffc079638020) Call trace: khugepaged+0x378/0x1af8 kthread+0xdc/0xf4 ret_from_fork+0xc/0x40 Code: 35001700 f0002c60 aa0703e3 f9009fa0 (f94000e0) ---[ end trace 637503d8e28ae69e ]--- Kernel panic - not syncing: Fatal exception CPU2: stopping CPU: 2 PID: 0 Comm: swapper/2 Tainted: G D W 4.3.0-rc6-next-20151022ajb-00001-g32f3386-dirty #3 Hardware name: linux,dummy-virt (DT) [akpm@linux-foundation.org: fix fat-fingered merge resolution] Signed-off-by: yalin wang <yalin.wang2010@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/trace/events/huge_memory.h12
-rw-r--r--mm/huge_memory.c6
2 files changed, 9 insertions, 9 deletions
diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h
index 0f803d2783e3..47c6212d8f3c 100644
--- a/include/trace/events/huge_memory.h
+++ b/include/trace/events/huge_memory.h
@@ -46,10 +46,10 @@ SCAN_STATUS
TRACE_EVENT(mm_khugepaged_scan_pmd,
- TP_PROTO(struct mm_struct *mm, unsigned long pfn, bool writable,
+ TP_PROTO(struct mm_struct *mm, struct page *page, bool writable,
bool referenced, int none_or_zero, int status),
- TP_ARGS(mm, pfn, writable, referenced, none_or_zero, status),
+ TP_ARGS(mm, page, writable, referenced, none_or_zero, status),
TP_STRUCT__entry(
__field(struct mm_struct *, mm)
@@ -62,7 +62,7 @@ TRACE_EVENT(mm_khugepaged_scan_pmd,
TP_fast_assign(
__entry->mm = mm;
- __entry->pfn = pfn;
+ __entry->pfn = page ? page_to_pfn(page) : -1;
__entry->writable = writable;
__entry->referenced = referenced;
__entry->none_or_zero = none_or_zero;
@@ -104,10 +104,10 @@ TRACE_EVENT(mm_collapse_huge_page,
TRACE_EVENT(mm_collapse_huge_page_isolate,
- TP_PROTO(unsigned long pfn, int none_or_zero,
+ TP_PROTO(struct page *page, int none_or_zero,
bool referenced, bool writable, int status),
- TP_ARGS(pfn, none_or_zero, referenced, writable, status),
+ TP_ARGS(page, none_or_zero, referenced, writable, status),
TP_STRUCT__entry(
__field(unsigned long, pfn)
@@ -118,7 +118,7 @@ TRACE_EVENT(mm_collapse_huge_page_isolate,
),
TP_fast_assign(
- __entry->pfn = pfn;
+ __entry->pfn = page ? page_to_pfn(page) : -1;
__entry->none_or_zero = none_or_zero;
__entry->referenced = referenced;
__entry->writable = writable;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 2d1ffe9d0e26..fd3a07b3e6f4 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2072,7 +2072,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
if (likely(writable)) {
if (likely(referenced)) {
result = SCAN_SUCCEED;
- trace_mm_collapse_huge_page_isolate(page_to_pfn(page), none_or_zero,
+ trace_mm_collapse_huge_page_isolate(page, none_or_zero,
referenced, writable, result);
return 1;
}
@@ -2082,7 +2082,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
out:
release_pte_pages(pte, _pte);
- trace_mm_collapse_huge_page_isolate(page_to_pfn(page), none_or_zero,
+ trace_mm_collapse_huge_page_isolate(page, none_or_zero,
referenced, writable, result);
return 0;
}
@@ -2580,7 +2580,7 @@ out_unmap:
collapse_huge_page(mm, address, hpage, vma, node);
}
out:
- trace_mm_khugepaged_scan_pmd(mm, page_to_pfn(page), writable, referenced,
+ trace_mm_khugepaged_scan_pmd(mm, page, writable, referenced,
none_or_zero, result);
return ret;
}