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| author | Hugh Dickins <hughd@google.com> | 2012-01-12 17:19:54 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-12 20:13:10 -0800 |
| commit | 90b3feaec8ffb167abd8903bf111605c2f035aa8 (patch) | |
| tree | 503c27c343397e1c94dce61e922fae18c7cd7172 | |
| parent | 12d27107867fc7216e8faaff0b894b0f162dcf75 (diff) | |
| download | linux-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>
| -rw-r--r-- | mm/memcontrol.c | 17 |
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 |