From: Masami Hiramatsu <masami.hiramatsu@gmail.com>
To: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com>
Cc: rostedt@goodmis.org, mingo@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tracing/probe: fix memleak in fetch_op_data operations
Date: Tue, 16 Jun 2020 17:41:06 +0900 [thread overview]
Message-ID: <20200616174106.8b61410d50ce20e010ad6f4e@gmail.com> (raw)
In-Reply-To: <20200615143034.GA1734@cosmos>
On Mon, 15 Jun 2020 20:00:38 +0530
Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com> wrote:
> kmemleak report:
> [<57dcc2ca>] __kmalloc_track_caller+0x139/0x2b0
> [<f1c45d0f>] kstrndup+0x37/0x80
> [<f9761eb0>] parse_probe_arg.isra.7+0x3cc/0x630
> [<055bf2ba>] traceprobe_parse_probe_arg+0x2f5/0x810
> [<655a7766>] trace_kprobe_create+0x2ca/0x950
> [<4fc6a02a>] create_or_delete_trace_kprobe+0xf/0x30
> [<6d1c8a52>] trace_run_command+0x67/0x80
> [<be812cc0>] trace_parse_run_command+0xa7/0x140
> [<aecfe401>] probes_write+0x10/0x20
> [<2027641c>] __vfs_write+0x30/0x1e0
> [<6a4aeee1>] vfs_write+0x96/0x1b0
> [<3517fb7d>] ksys_write+0x53/0xc0
> [<dad91db7>] __ia32_sys_write+0x15/0x20
> [<da347f64>] do_syscall_32_irqs_on+0x3d/0x260
> [<fd0b7e7d>] do_fast_syscall_32+0x39/0xb0
> [<ea5ae810>] entry_SYSENTER_32+0xaf/0x102
>
> Post parse_probe_arg(), the FETCH_OP_DATA operation type is overwritten
> to FETCH_OP_ST_STRING, as a result memory is never freed since
> traceprobe_free_probe_arg() iterates only over SYMBOL and DATA op types
>
> Setup fetch string operation correctly after fetch_op_data operation.
>
Oops, Good catch! (I've commented it but not coded...)
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
And,
Fixes: a42e3c4de964 ("tracing/probe: Add immediate string parameter support")
Cc: stable@vger.kernel.org
Thank you!
> Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com>
> ---
> kernel/trace/trace_probe.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> index b8a928e..d2867cc 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -639,8 +639,8 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size,
> ret = -EINVAL;
> goto fail;
> }
> - if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM) ||
> - parg->count) {
> + if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
> + code->op == FETCH_OP_DATA) || parg->count) {
> /*
> * IMM, DATA and COMM is pointing actual address, those
> * must be kept, and if parg->count != 0, this is an
> --
> 2.7.4
>
--
Masami Hiramatsu
next prev parent reply other threads:[~2020-06-16 8:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-15 14:30 [PATCH] tracing/probe: fix memleak in fetch_op_data operations Vamshi K Sthambamkadi
2020-06-15 21:13 ` Steven Rostedt
2020-06-16 8:46 ` Masami Hiramatsu
2020-06-16 14:19 ` Oleg Nesterov
2020-06-16 16:21 ` Srikar Dronamraju
2020-06-16 8:41 ` Masami Hiramatsu [this message]
2020-06-15 15:10 Markus Elfring
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