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From: Dmitry Vyukov <dvyukov@google.com>
To: Shankara Pailoor <sp3485@columbia.edu>
Cc: LKML <linux-kernel@vger.kernel.org>,
	syzkaller <syzkaller@googlegroups.com>
Subject: Re: Possible Memory Leak in KCOV Linux 4.15-rc1
Date: Sat, 20 Jan 2018 13:38:52 +0100	[thread overview]
Message-ID: <CACT4Y+ZcbKWkS5Zd6uAynL=PKF7KbTBWrxnkkPXb0spV0-EDsg@mail.gmail.com> (raw)
In-Reply-To: <CAASgV=tW5gDF8-bq_t+LYNaoLOnCbL94_u8+uF=s36-JNaGP_w@mail.gmail.com>

On Fri, Jan 19, 2018 at 8:29 PM, Shankara Pailoor <sp3485@columbia.edu> wrote:
> Hi Dmitry,
>
> I added support for kcov in strace and I have been tracing a fairly
> large program but after a little while, I notice that when I mmap a
> new cover buffer, the call fails with ENOMEM. After killing the
> program, I try and rerun and I notice that there is nearly no memory
> on the system. When I do a kmemleak scan I get the following reports:
>
> I believe the problem occurs when I try and setup the kcov buffer
> again after an exec. Instead of reusing the old file descriptor I open
> kcov again within that process. In that case, I don't know what
> happens to the old kcov struct.
>
> I don't see a maintainers list for kcov so I decided to email you
> directly. Let me know what more information I can provide.


Hi Shankara,

Looks bad. Can you provide a reproducer?
We extensively use kcov with syzkaller, but have not observed such
leaks. Also I don't see anything obvious in the code.

Thanks

  reply	other threads:[~2018-01-20 12:39 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-19 19:29 Possible Memory Leak in KCOV Linux 4.15-rc1 Shankara Pailoor
2018-01-20 12:38 ` Dmitry Vyukov [this message]
2018-01-20 15:01   ` Shankara Pailoor
2018-01-20 15:06     ` Dmitry Vyukov
2018-01-21  9:11       ` Shankara Pailoor
2018-01-21 17:54         ` Shankara Pailoor
2018-01-22  8:29           ` Dmitry Vyukov

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