linux-kernel - [PATCH v2] io-wq: close cancel gap for hashed linked work

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <c38a2421e15e3aaa5c55e3e0d7ddca4c77d178e1.1584898199.git.asml.silence@gmail.com>
Date:   Sun, 22 Mar 2020 20:33:16 +0300
From:   Pavel Begunkov <asml.silence@...il.com>
To:     Jens Axboe <axboe@...nel.dk>, io-uring@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2] io-wq: close cancel gap for hashed linked work

After io_assign_current_work() of a linked work, it can be decided to
offloaded to another thread so doing io_wqe_enqueue(). However, until
next io_assign_current_work() it can be cancelled, that isn't handled.

Don't assign it, if it's not going to be executed.

Fixes: 60cf46ae605446feb0c43c472c0 ("io-wq: hash dependent work")
Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
---
 fs/io-wq.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 9541df2729de..b3fb61ec0870 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -485,7 +485,7 @@ static void io_worker_handle_work(struct io_worker *worker)
 	struct io_wq *wq = wqe->wq;
 
 	do {
-		struct io_wq_work *work;
+		struct io_wq_work *work, *assign_work;
 		unsigned int hash;
 get_next:
 		/*
@@ -522,10 +522,14 @@ static void io_worker_handle_work(struct io_worker *worker)
 			hash = io_get_work_hash(work);
 			work->func(&work);
 			work = (old_work == work) ? NULL : work;
-			io_assign_current_work(worker, work);
+
+			assign_work = work;
+			if (work && io_wq_is_hashed(work))
+				assign_work = NULL;
+			io_assign_current_work(worker, assign_work);
 			wq->free_work(old_work);
 
-			if (work && io_wq_is_hashed(work)) {
+			if (work && !assign_work) {
 				io_wqe_enqueue(wqe, work);
 				work = NULL;
 			}
-- 
2.24.0