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authorHugh Dickins <hughd@google.com>2012-01-12 17:19:54 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-12 20:13:10 -0800
commit90b3feaec8ffb167abd8903bf111605c2f035aa8 (patch)
tree503c27c343397e1c94dce61e922fae18c7cd7172 /mm
parent12d27107867fc7216e8faaff0b894b0f162dcf75 (diff)
downloadlinux-stericsson-90b3feaec8ffb167abd8903bf111605c2f035aa8.tar.gz
memcg: fix mem_cgroup_print_bad_page
If DEBUG_VM, mem_cgroup_print_bad_page() is called whenever bad_page() shows a "Bad page state" message, removes page from circulation, adds a taint and continues. This is at a very low level, often when a spinlock is held (sometimes when page table lock is held, for example). We want to recover from this badness, not make it worse: we must not kmalloc memory here, we must not do a cgroup path lookup via dubious pointers. No doubt that code was useful to debug a particular case at one time, and may be again, but take it out of the mainline kernel. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memcontrol.c17
1 files changed, 1 insertions, 16 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9f2f64697409..602207be9853 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3364,23 +3364,8 @@ void mem_cgroup_print_bad_page(struct page *page)
pc = lookup_page_cgroup_used(page);
if (pc) {
- int ret = -1;
- char *path;
-
- printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p",
+ printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
pc, pc->flags, pc->mem_cgroup);
-
- path = kmalloc(PATH_MAX, GFP_KERNEL);
- if (path) {
- rcu_read_lock();
- ret = cgroup_path(pc->mem_cgroup->css.cgroup,
- path, PATH_MAX);
- rcu_read_unlock();
- }
-
- printk(KERN_CONT "(%s)\n",
- (ret < 0) ? "cannot get the path" : path);
- kfree(path);
}
}
#endif