From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Love Subject: [PATCH -next] ashmem: Fix ashmem_shrink deadlock. Date: Wed, 1 May 2013 09:56:13 -0400 Message-ID: <1367416573-5430-1-git-send-email-rlove@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devel-bounces@linuxdriverproject.org Sender: "devel" To: Greg Kroah-Hartman , Shankar Brahadeeswaran , Dan Carpenter , LKML , Bjorn Bringert , devel , Hugh Dickins , Anjana V Kumar , Dad , linux-next List-Id: linux-next.vger.kernel.org Don't acquire ashmem_mutex in ashmem_shrink if we've somehow recursed into the shrinker code from within ashmem. Just bail out, avoiding a deadlock. This is fine, as ashmem cache pruning is advisory anyhow. Signed-off-by: Robert Love --- drivers/staging/android/ashmem.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c index e681bdd..82c6768 100644 --- a/drivers/staging/android/ashmem.c +++ b/drivers/staging/android/ashmem.c @@ -363,7 +363,11 @@ static int ashmem_shrink(struct shrinker *s, struct shrink_control *sc) if (!sc->nr_to_scan) return lru_count; - mutex_lock(&ashmem_mutex); + /* avoid recursing into this code from within ashmem itself */ + if (!mutex_trylock(&ashmem_mutex)) { + return -1; + } + list_for_each_entry_safe(range, next, &ashmem_lru_list, lru) { loff_t start = range->pgstart * PAGE_SIZE; loff_t end = (range->pgend + 1) * PAGE_SIZE; -- 1.8.2.1