mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE
Most of the VM_BUG_ON assertions are performed on a page. Usually, when
one of these assertions fails we'll get a BUG_ON with a call stack and
the registers.
I've recently noticed based on the requests to add a small piece of code
that dumps the page to various VM_BUG_ON sites that the page dump is
quite useful to people debugging issues in mm.
This patch adds a VM_BUG_ON_PAGE(cond, page) which beyond doing what
VM_BUG_ON() does, also dumps the page before executing the actual
BUG_ON.
[akpm@linux-foundation.org: fix up includes]
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7890ce9..72f2d90 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2897,7 +2897,7 @@
unsigned short id;
swp_entry_t ent;
- VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
pc = lookup_page_cgroup(page);
lock_page_cgroup(pc);
@@ -2931,7 +2931,7 @@
bool anon;
lock_page_cgroup(pc);
- VM_BUG_ON(PageCgroupUsed(pc));
+ VM_BUG_ON_PAGE(PageCgroupUsed(pc), page);
/*
* we don't need page_cgroup_lock about tail pages, becase they are not
* accessed by any other context at this point.
@@ -2966,7 +2966,7 @@
if (lrucare) {
if (was_on_lru) {
lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
- VM_BUG_ON(PageLRU(page));
+ VM_BUG_ON_PAGE(PageLRU(page), page);
SetPageLRU(page);
add_page_to_lru_list(page, lruvec, page_lru(page));
}
@@ -3780,7 +3780,7 @@
if (!memcg)
return;
- VM_BUG_ON(mem_cgroup_is_root(memcg));
+ VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
}
#else
@@ -3859,7 +3859,7 @@
bool anon = PageAnon(page);
VM_BUG_ON(from == to);
- VM_BUG_ON(PageLRU(page));
+ VM_BUG_ON_PAGE(PageLRU(page), page);
/*
* The page is isolated from LRU. So, collapse function
* will not handle this page. But page splitting can happen.
@@ -3952,7 +3952,7 @@
parent = root_mem_cgroup;
if (nr_pages > 1) {
- VM_BUG_ON(!PageTransHuge(page));
+ VM_BUG_ON_PAGE(!PageTransHuge(page), page);
flags = compound_lock_irqsave(page);
}
@@ -3986,7 +3986,7 @@
if (PageTransHuge(page)) {
nr_pages <<= compound_order(page);
- VM_BUG_ON(!PageTransHuge(page));
+ VM_BUG_ON_PAGE(!PageTransHuge(page), page);
/*
* Never OOM-kill a process for a huge page. The
* fault handler will fall back to regular pages.
@@ -4006,8 +4006,8 @@
{
if (mem_cgroup_disabled())
return 0;
- VM_BUG_ON(page_mapped(page));
- VM_BUG_ON(page->mapping && !PageAnon(page));
+ VM_BUG_ON_PAGE(page_mapped(page), page);
+ VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page);
VM_BUG_ON(!mm);
return mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_ANON);
@@ -4211,7 +4211,7 @@
if (PageTransHuge(page)) {
nr_pages <<= compound_order(page);
- VM_BUG_ON(!PageTransHuge(page));
+ VM_BUG_ON_PAGE(!PageTransHuge(page), page);
}
/*
* Check if our page_cgroup is valid
@@ -4303,7 +4303,7 @@
/* early check. */
if (page_mapped(page))
return;
- VM_BUG_ON(page->mapping && !PageAnon(page));
+ VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page);
/*
* If the page is in swap cache, uncharge should be deferred
* to the swap path, which also properly accounts swap usage
@@ -4323,8 +4323,8 @@
void mem_cgroup_uncharge_cache_page(struct page *page)
{
- VM_BUG_ON(page_mapped(page));
- VM_BUG_ON(page->mapping);
+ VM_BUG_ON_PAGE(page_mapped(page), page);
+ VM_BUG_ON_PAGE(page->mapping, page);
__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
}
@@ -6880,7 +6880,7 @@
enum mc_target_type ret = MC_TARGET_NONE;
page = pmd_page(pmd);
- VM_BUG_ON(!page || !PageHead(page));
+ VM_BUG_ON_PAGE(!page || !PageHead(page), page);
if (!move_anon())
return ret;
pc = lookup_page_cgroup(page);