In vmap_pte_range, BUG_ON is called when page is already mapped,
It doesn't give enough information to debug further.
Dumping page owner information alongwith BUG_ON will be more useful
in case of multiple page mapping.
Example:
[ 18.258806] page_owner tracks the page as allocated
[ 18.258970] page last allocated via order 0, migratetype Unmovable, gfp_mask 0xcc0(GFP_KERNEL), pid 81, tgid 81 (insmod), ts 18257811008, free_ts 0
[ 18.259327] prep_new_page+0xa8/0x10c
[ 18.259455] get_page_from_freelist+0x7f8/0x1248
[ 18.259591] __alloc_pages+0x164/0x2b4
[ 18.259703] alloc_pages_mpol+0x88/0x230
[ 18.259821] alloc_pages+0x4c/0x7c
[ 18.259923] load_module+0x74/0x1af4
[ 18.260031] __do_sys_init_module+0x190/0x1fc
[ 18.260154] __arm64_sys_init_module+0x1c/0x28
[ 18.260280] invoke_syscall+0x44/0x108
[ 18.260394] el0_svc_common.constprop.0+0x40/0xe0
[ 18.260530] do_el0_svc_compat+0x1c/0x34
[ 18.260647] el0_svc_compat+0x2c/0x80
[ 18.260761] el0t_32_sync_handler+0x90/0x140
[ 18.260887] el0t_32_sync+0x194/0x198
[ 18.260996] page_owner free stack trace missing
[ 18.261143] ------------[ cut here ]------------
[ 18.261272] kernel BUG at mm/vmalloc.c:113!
Signed-off-by: Hariom Panthi <hariom1.p@xxxxxxxxxxx>
---
mm/vmalloc.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 68fa001648cc..9c91091887de 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -42,6 +42,7 @@
#include <linux/sched/mm.h>
#include <asm/tlbflush.h>
#include <asm/shmparam.h>
+#include <linux/page_owner.h>
#define CREATE_TRACE_POINTS
#include <trace/events/vmalloc.h>
@@ -96,6 +97,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
{
pte_t *pte;
u64 pfn;
+ struct page *page;
unsigned long size = PAGE_SIZE;
pfn = phys_addr >> PAGE_SHIFT;
@@ -103,7 +105,13 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
if (!pte)
return -ENOMEM;
do {
- BUG_ON(!pte_none(ptep_get(pte)));
+ if (!pte_none(ptep_get(pte))) {
+ if (pfn_valid(pfn)) {
+ page = pfn_to_page(pfn);
+ dump_page_owner(page);
+ }
+ BUG();
+ }
#ifdef CONFIG_HUGETLB_PAGE
size = arch_vmap_pte_range_map_size(addr, end, pfn, max_page_shift);
--
2.25.1
