linux-kernel - Re: [PATCH] io-wq: Fix memory leak in worker creation

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Message-Id: <166623279015.153364.8618304798678076215.b4-ty@kernel.dk>
Date:   Wed, 19 Oct 2022 19:26:30 -0700
From:   Jens Axboe <axboe@...nel.dk>
To:     Pavel Begunkov <asml.silence@...il.com>,
        Rafael Mendonca <rafaelmendsr@...il.com>
Cc:     io-uring@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] io-wq: Fix memory leak in worker creation

On Wed, 19 Oct 2022 22:47:09 -0300, Rafael Mendonca wrote:
> 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
> 
> [...]

Applied, thanks!

[1/1] io-wq: Fix memory leak in worker creation
      commit: 839a0c962971a5a95515c1637aede8a4fbc6547f

Best regards,
-- 
Jens Axboe