From: Rafael Mendonca <rafaelmendsr@gmail.com>
To: Jens Axboe <axboe@kernel.dk>, Pavel Begunkov <asml.silence@gmail.com>
Cc: Rafael Mendonca <rafaelmendsr@gmail.com>,
io-uring@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] io-wq: Fix memory leak in worker creation
Date: Wed, 19 Oct 2022 22:47:09 -0300 [thread overview]
Message-ID: <20221020014710.902201-1-rafaelmendsr@gmail.com> (raw)
If the CPU mask allocation for a node fails, then the memory allocated for
the 'io_wqe' struct of the current node doesn't get freed on the error
handling path, since it has not yet been added to the 'wqes' array.
This was spotted when fuzzing v6.1-rc1 with Syzkaller:
BUG: memory leak
unreferenced object 0xffff8880093d5000 (size 1024):
comm "syz-executor.2", pid 7701, jiffies 4295048595 (age 13.900s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000cb463369>] __kmem_cache_alloc_node+0x18e/0x720
[<00000000147a3f9c>] kmalloc_node_trace+0x2a/0x130
[<000000004e107011>] io_wq_create+0x7b9/0xdc0
[<00000000c38b2018>] io_uring_alloc_task_context+0x31e/0x59d
[<00000000867399da>] __io_uring_add_tctx_node.cold+0x19/0x1ba
[<000000007e0e7a79>] io_uring_setup.cold+0x1b80/0x1dce
[<00000000b545e9f6>] __x64_sys_io_uring_setup+0x5d/0x80
[<000000008a8a7508>] do_syscall_64+0x5d/0x90
[<000000004ac08bec>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
Fixes: 0e03496d1967 ("io-wq: use private CPU mask")
Signed-off-by: Rafael Mendonca <rafaelmendsr@gmail.com>
---
io_uring/io-wq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c
index c6536d4b2da0..6f1d0e5df23a 100644
--- a/io_uring/io-wq.c
+++ b/io_uring/io-wq.c
@@ -1164,10 +1164,10 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
wqe = kzalloc_node(sizeof(struct io_wqe), GFP_KERNEL, alloc_node);
if (!wqe)
goto err;
+ wq->wqes[node] = wqe;
if (!alloc_cpumask_var(&wqe->cpu_mask, GFP_KERNEL))
goto err;
cpumask_copy(wqe->cpu_mask, cpumask_of_node(node));
- wq->wqes[node] = wqe;
wqe->node = alloc_node;
wqe->acct[IO_WQ_ACCT_BOUND].max_workers = bounded;
wqe->acct[IO_WQ_ACCT_UNBOUND].max_workers =
--
2.34.1
next reply other threads:[~2022-10-20 1:47 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-20 1:47 Rafael Mendonca [this message]
2022-10-20 2:26 ` Jens Axboe
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