From: Matthew Wilcox <willy@infradead.org>
To: Peng Fan <fanpeng@loongson.cn>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Xuefeng Li <lixuefeng@loongson.cn>,
Tiezhu Yang <yangtiezhu@loongson.cn>
Subject: Re: [PATCH] fs/read_write.c: Fix memory leak in read_write.c
Date: Wed, 24 Jun 2020 04:24:47 +0100 [thread overview]
Message-ID: <20200624032447.GK21350@casper.infradead.org> (raw)
In-Reply-To: <1592968023-20383-1-git-send-email-fanpeng@loongson.cn>
On Wed, Jun 24, 2020 at 11:07:03AM +0800, Peng Fan wrote:
> kmemleak report:
> unreferenced object 0x98000002bb591d00 (size 256):
> comm "ftest03", pid 24778, jiffies 4301603810 (age 490.665s)
> hex dump (first 32 bytes):
> 00 01 04 20 01 00 00 00 80 00 00 00 00 00 00 00 ... ............
> f0 02 04 20 01 00 00 00 80 00 00 00 00 00 00 00 ... ............
> backtrace:
> [<0000000050b162cb>] __kmalloc+0x234/0x438
> [<00000000491da9c7>] rw_copy_check_uvector+0x1ac/0x1f0
> [<00000000b0dddb43>] import_iovec+0x50/0xe8
> [<00000000ae843d73>] vfs_readv+0x50/0xb0
> [<00000000c7216b06>] do_readv+0x80/0x160
> [<00000000cad79c3f>] syscall_common+0x34/0x58
>
> This is because "iov" allocated by kmalloc() is not destroyed. Under normal
> circumstances, "ret_pointer" should be equal to "iov". But if the previous
> statements fails to execute, and the allocation is successful, then the
> block of memory will not be released, because it is necessary to
> determine whether they are equal. So we need to change the order.
This patch doesn't make sense. It will _introduce_ a memory leak,
not fix one.
prev parent reply other threads:[~2020-06-24 3:25 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-24 3:07 Peng Fan
2020-06-24 3:24 ` Matthew Wilcox [this message]
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