Messages in this thread Patch in this message | | | Date | Mon, 4 May 2009 17:26:59 -0700 (PDT) | From | David Rientjes <> | Subject | [patch 4/7] oom: fix possible android low memory killer NULL pointer |
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get_mm_rss() atomically dereferences the actual without checking for a NULL pointer, which is possible since task_lock() is not held.
Cc: San Mehat <san@android.com> Signed-off-by: David Rientjes <rientjes@google.com> --- drivers/staging/android/lowmemorykiller.c | 10 ++++++++-- 1 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c --- a/drivers/staging/android/lowmemorykiller.c +++ b/drivers/staging/android/lowmemorykiller.c @@ -92,12 +92,18 @@ static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask) for_each_process(p) { int oom_adj; - if (!p->mm) + task_lock(p); + if (!p->mm) { + task_unlock(p); continue; + } oom_adj = p->oomkilladj; - if (oom_adj < min_adj) + if (oom_adj < min_adj) { + task_unlock(p); continue; + } tasksize = get_mm_rss(p->mm); + task_unlock(p); if (tasksize <= 0) continue; if (selected) {
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