From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932167AbcLBH0p (ORCPT ); Fri, 2 Dec 2016 02:26:45 -0500 Received: from outboundhk.mxmail.xiaomi.com ([207.226.244.122]:22139 "EHLO xiaomi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750955AbcLBH0n (ORCPT ); Fri, 2 Dec 2016 02:26:43 -0500 From: cuilifei To: CC: , cuilifei Subject: [PATCH] fuse: freezing abort when use wait_event_killable{,_exclusive}(). Date: Fri, 2 Dec 2016 15:26:20 +0800 Message-ID: <1480663580-20280-1-git-send-email-cuilifei@xiaomi.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.237.10.122] X-ClientProxiedBy: CNCAS3.mioffice.cn (10.237.8.133) To cnbox4.mioffice.cn (10.237.8.144) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Freezing process can abort when a client is waiting uninterruptibly for a response. Add new macro wait_fatal_freezable to try to fix it. Signed-off-by: cuilifei --- fs/fuse/dev.c | 45 +++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 41 insertions(+), 4 deletions(-) diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 70ea57c..3447ecc 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -23,6 +23,22 @@ MODULE_ALIAS_MISCDEV(FUSE_MINOR); MODULE_ALIAS("devname:fuse"); +#define wait_fatal_freezable(wq, condition, exclusive) \ +({ \ + int __ret = 0; \ + do { \ + if (exclusive) \ + __ret = wait_event_interruptible_exclusive(wq, \ + condition); \ + else \ + __ret = wait_event_interruptible(wq, \ + condition); \ + if (!__ret || fatal_signal_pending(current)) \ + break; \ + } while (try_to_freeze()); \ + __ret; \ +}) + static struct kmem_cache *fuse_req_cachep; static struct fuse_dev *fuse_get_dev(struct file *file) @@ -99,6 +115,19 @@ void fuse_request_free(struct fuse_req *req) kmem_cache_free(fuse_req_cachep, req); } +static void block_sigs(sigset_t *oldset) +{ + sigset_t mask; + + siginitsetinv(&mask, sigmask(SIGKILL)); + sigprocmask(SIG_BLOCK, &mask, oldset); +} + +static void restore_sigs(sigset_t *oldset) +{ + sigprocmask(SIG_SETMASK, oldset, NULL); +} + void __fuse_get_request(struct fuse_req *req) { atomic_inc(&req->count); @@ -134,13 +163,18 @@ static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages, bool for_background) { struct fuse_req *req; + sigset_t oldset; + int intr; int err; atomic_inc(&fc->num_waiting); if (fuse_block_alloc(fc, for_background)) { err = -EINTR; - if (wait_event_killable_exclusive(fc->blocked_waitq, - !fuse_block_alloc(fc, for_background))) + block_sigs(&oldset); + intr = wait_fatal_freezable(fc->blocked_waitq, + !fuse_block_alloc(fc, for_background), true); + restore_sigs(&oldset); + if (intr) goto out; } /* Matches smp_wmb() in fuse_set_initialized() */ @@ -427,9 +461,12 @@ static void request_wait_answer(struct fuse_conn *fc, struct fuse_req *req) } if (!test_bit(FR_FORCE, &req->flags)) { + sigset_t oldset; /* Only fatal signals may interrupt this */ - err = wait_event_killable(req->waitq, - test_bit(FR_FINISHED, &req->flags)); + block_sigs(&oldset); + err = wait_fatal_freezable(req->waitq, + test_bit(FR_FINISHED, &req->flags), false); + restore_sigs(&oldset); if (!err) return; -- 1.9.1