[PATCH 8/8] badpage: KERN_ALERT BUG instead of KERN_EMERG

Hugh Dickins
2008-12-01T00:48:17Z

bad_page() and rmap Eeek messages have said KERN_EMERG for a few years,
which I've followed in print_bad_pte(). These are serious system errors,
on a par with BUGs, but they're not quite emergencies, and we do our best
to carry on: say KERN_ALERT "BUG: " like the x86 oops does.

And remove the "Trying to fix it up, but a reboot is needed" line:
it's not untrue, but I hope the KERN_ALERT "BUG: " conveys as much.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
---
I've left this proposal until last, expecting some opposition.

Considered adding oops_begin() and oops_end(),
but I'm not at all sure that would work out well for these.

mm/memory.c | 15 ++++++++-------
mm/page_alloc.c | 9 ++++-----
2 files changed, 12 insertions(+), 12 deletions(-)

--- badpage7/mm/memory.c 2008-11-28 20:40:50.000000000 +0000
+++ badpage8/mm/memory.c 2008-11-28 20:40:52.000000000 +0000
@@ -397,8 +397,8 @@ static void print_bad_pte(struct vm_area
return;
}
if (nr_unshown) {
- printk(KERN_EMERG
- "Bad page map: %lu messages suppressed\n",
+ printk(KERN_ALERT
+ "BUG: Bad page map: %lu messages suppressed\n",
nr_unshown);
nr_unshown = 0;
}
@@ -410,26 +410,27 @@ static void print_bad_pte(struct vm_area
mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
index = linear_page_index(vma, addr);

- printk(KERN_EMERG "Bad page map in process %s pte:%08llx pmd:%08llx\n",
+ printk(KERN_ALERT
+ "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
current->comm,
(long long)pte_val(pte), (long long)pmd_val(*pmd));
if (page) {
- printk(KERN_EMERG
+ printk(KERN_ALERT
"page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
page, (void *)page->flags, page_count(page),
page_mapcount(page), page->mapping, page->index);
}
- printk(KERN_EMERG
+ printk(KERN_ALERT
"addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
(void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
/*
* Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
*/
if (vma->vm_ops)
- print_symbol(KERN_EMERG "vma->vm_ops->fault: %s\n",
+ print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n",
(unsigned long)vma->vm_ops->fault);
if (vma->vm_file && vma->vm_file->f_op)
- print_symbol(KERN_EMERG "vma->vm_file->f_op->mmap: %s\n",
+ print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n",
(unsigned long)vma->vm_file->f_op->mmap);
dump_stack();
add_taint(TAINT_BAD_PAGE);
--- badpage7/mm/page_alloc.c 2008-11-28 20:40:50.000000000 +0000
+++ badpage8/mm/page_alloc.c 2008-11-28 20:40:52.000000000 +0000
@@ -237,8 +237,8 @@ static void bad_page(struct page *page)
goto out;
}
if (nr_unshown) {
- printk(KERN_EMERG
- "Bad page state: %lu messages suppressed\n",
+ printk(KERN_ALERT
+ "BUG: Bad page state: %lu messages suppressed\n",
nr_unshown);
nr_unshown = 0;
}
@@ -247,13 +247,12 @@ static void bad_page(struct page *page)
if (nr_shown++ == 0)
resume = jiffies + 60 * HZ;

- printk(KERN_EMERG "Bad page state in process %s pfn:%05lx\n",
+ printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n",
current->comm, page_to_pfn(page));
- printk(KERN_EMERG
+ printk(KERN_ALERT
"page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
page, (void *)page->flags, page_count(page),
page_mapcount(page), page->mapping, page->index);
- printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n");

dump_stack();