From: Matan Azrad <matan@mellanox.com>
To: "Gaëtan Rivet" <gaetan.rivet@6wind.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
Raslan Darawsheh <rasland@mellanox.com>,
"stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-stable] [PATCH] net/failsafe: fix exec parameter parsing error flow
Date: Wed, 30 Aug 2017 06:11:47 +0000 [thread overview]
Message-ID: <DB6PR0502MB30488C338F4C76B6608E1842D29C0@DB6PR0502MB3048.eurprd05.prod.outlook.com> (raw)
In-Reply-To: <20170829163339.GP8124@bidouze.vm.6wind.com>
Hi Gaetan
> -----Original Message-----
> From: Gaëtan Rivet [mailto:gaetan.rivet@6wind.com]
> Sent: Tuesday, August 29, 2017 7:34 PM
> To: Matan Azrad <matan@mellanox.com>
> Cc: dev@dpdk.org; Raslan Darawsheh <rasland@mellanox.com>;
> stable@dpdk.org
> Subject: Re: [PATCH] net/failsafe: fix exec parameter parsing error flow
>
> Hi Matan,
>
> On Tue, Aug 29, 2017 at 05:59:08PM +0300, Matan Azrad wrote:
> > The corrupted code returns success value in case of the execution
> > process output stream is empty(EOF).
> > It causes to segmentation fault while failsafe polls this command line
> > again, than gets success and tries to do hotplug add to the sub device
> > by uninitialized pointer dereferencing.
> >
>
> This is a bug and should be fixed, thanks.
>
> > Morever, when the output is not empty but uncorrect, failsafe returns
> > error for its probe function while the expected behavior is to do
> > polling until the output is correct.
> >
>
> The expected behavior is for the fail-safe to return an error if the execution
> of the given command returns an error.
>
> The intention is that users writing such script would be able to output a blank
> lines in case there is nothing to probe, but still remain aware of issues during
> the execution of the command.
>
> The fail-safe ignores errors pertaining to absent devices due to its nature.
> This does not mean that it should ignore all errors and try to keep on going
> while everything else is on fire.
>
> The contract with the user is that "blank line" without other errors means
> "absent device". Garbled output or return code != 0 means runtime error
> and should be thrown to the user / application.
>
OK, good, I would have signed this contract :)
What's about if the parsing is not empty and out with error in the polling process?
I think in current code failsafe just continues normally and tries again on next polling time.
Because of this code I thought that if error occurs we should poll it again...
Can you please add it (the contract) in failsafe documentation for exec parameter?
> > The fix changes the return value to be -ENODEV for this sub device in
> > the two cases.
> > By this way, failsafe tries to parse this sub device parameter by exec
> > method until the output is correct.
> >
>
> The issue is that this portion of the code will be heavily modified anyway. The
> errno handling is erroneous and must be fixed, which is in conflict with your
> patch.
>
> I will send the intended fix shortly, referencing this patch and the issue your
> highlighted, but both patch won't be compatible.
>
Good, no problems.
> > Fixes: a0194d828100 ("net/failsafe: add flexible device definition")
> > Fixes: 35ffe4208140 ("net/failsafe: fix missing pclose after popen")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Matan Azrad <matan@mellanox.com>
> > ---
> > drivers/net/failsafe/failsafe_args.c | 6 +++++-
> > 1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/failsafe/failsafe_args.c
> > b/drivers/net/failsafe/failsafe_args.c
> > index 645c885..61c55df 100644
> > --- a/drivers/net/failsafe/failsafe_args.c
> > +++ b/drivers/net/failsafe/failsafe_args.c
> > @@ -157,12 +157,16 @@ fs_execute_cmd(struct sub_device *sdev, char
> *cmdline)
> > ret = fs_parse_device(sdev, output);
> > if (ret) {
> > ERROR("Parsing device '%s' failed", output);
> > + ret = -ENODEV;
Remove the above line for probe function error report.
> > goto ret_pclose;
> > }
> > ret_pclose:
> > pclose_ret = pclose(fp);
> > if (pclose_ret) {
> > - pclose_ret = errno;
> > + if (errno == 0)
> > + errno = -(pclose_ret = ret);
> > + else
> > + pclose_ret = errno;
> > ERROR("pclose: %s", strerror(errno));
> > errno = old_err;
> > return pclose_ret;
> > --
> > 2.7.4
> >
>
> Best regards,
> --
> Gaëtan Rivet
> 6WIND
Thanks,
Matan Azrad
next prev parent reply other threads:[~2017-08-30 6:11 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-29 14:59 Matan Azrad
2017-08-29 16:33 ` Gaëtan Rivet
2017-08-30 6:11 ` Matan Azrad [this message]
2017-08-30 14:24 ` Gaëtan Rivet
2017-08-30 15:32 ` Matan Azrad
2017-08-30 15:59 ` [dpdk-stable] [PATCH] net/failsafe: fix errno set on command execution Gaetan Rivet
2017-09-01 15:59 ` Ferruh Yigit
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