From 16fd0fe4aa92d0d621ecfe21de86f7fdcfa41947 Mon Sep 17 00:00:00 2001 From: yalin wang Date: Thu, 21 Jan 2016 16:40:30 -0800 Subject: 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 Acked-by: Vlastimil Babka Acked-by: Kirill A. Shutemov Acked-by: David Rientjes Cc: Cyrill Gorcunov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/huge_memory.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'mm/huge_memory.c') 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; } -- cgit v1.2.3