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[71.184.117.43]) by smtp.gmail.com with ESMTPSA id y125sm1818592qkd.49.2019.03.06.16.27.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 Mar 2019 16:27:42 -0800 (PST) From: Qian Cai To: tj@kernel.org, jiangshanlai@gmail.com Cc: peterz@infradead.org, mingo@redhat.com, will.deacon@arm.com, bvanassche@acm.org, catalin.marinas@arm.com, linux-kernel@vger.kernel.org, Qian Cai Subject: [PATCH] workqueue: fix a memory leak in wq->lock_name Date: Wed, 6 Mar 2019 19:27:31 -0500 Message-Id: <20190307002731.47371-1-cai@lca.pw> X-Mailer: git-send-email 2.17.2 (Apple Git-113) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The commit 669de8bda87b ("kernel/workqueue: Use dynamic lockdep keys for workqueues") introduced a memory leak as wq_free_lockdep() calls kfree(wq->lock_name) but wq_init_lockdep() does not point wq->lock_name to the newly allocated slab object. This can be reproduced by running LTP fallocate04 followed by oom01 tests. unreferenced object 0xc0000005876384d8 (size 64): comm "fallocate04", pid 26972, jiffies 4297139141 (age 40370.480s) hex dump (first 32 bytes): 28 77 71 5f 63 6f 6d 70 6c 65 74 69 6f 6e 29 65 (wq_completion)e 78 74 34 2d 72 73 76 2d 63 6f 6e 76 65 72 73 69 xt4-rsv-conversi backtrace: [<00000000cb452883>] kvasprintf+0x6c/0xe0 [<000000004654ddac>] kasprintf+0x34/0x60 [<000000001c68f311>] alloc_workqueue+0x1f8/0x6ac [<0000000003c2ad83>] ext4_fill_super+0x23d4/0x3c80 [ext4] [<0000000006610538>] mount_bdev+0x25c/0x290 [<00000000bcf955ec>] ext4_mount+0x28/0x50 [ext4] [<0000000016e08fd3>] legacy_get_tree+0x4c/0xb0 [<0000000042b6a5fc>] vfs_get_tree+0x6c/0x190 [<00000000268ab022>] do_mount+0xb9c/0x1100 [<00000000698e6898>] ksys_mount+0x158/0x180 [<0000000064e391fd>] sys_mount+0x20/0x30 [<00000000ba378f12>] system_call+0x5c/0x70 Fixes: 669de8bda87b ("kernel/workqueue: Use dynamic lockdep keys for workqueues") Reviewed-by: Bart Van Assche Signed-off-by: Qian Cai --- kernel/workqueue.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index e163e7a7f5e5..ade0d47ec086 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3348,6 +3348,8 @@ static void wq_init_lockdep(struct workqueue_struct *wq) lock_name = kasprintf(GFP_KERNEL, "%s%s", "(wq_completion)", wq->name); if (!lock_name) lock_name = wq->name; + + wq->lock_name = lock_name; lockdep_init_map(&wq->lockdep_map, lock_name, &wq->key, 0); } -- 2.17.2 (Apple Git-113)