From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matan Azrad Subject: Re: [PATCH] net/failsafe: fix exec parameter parsing error flow Date: Wed, 30 Aug 2017 15:32:46 +0000 Message-ID: References: <1504018748-4766-1-git-send-email-matan@mellanox.com> <20170829163339.GP8124@bidouze.vm.6wind.com> <20170830142443.GB3049@bidouze.vm.6wind.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Cc: "dev@dpdk.org" , Raslan Darawsheh , "stable@dpdk.org" To: =?iso-8859-1?Q?Ga=EBtan_Rivet?= Return-path: In-Reply-To: <20170830142443.GB3049@bidouze.vm.6wind.com> Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Hi Gaetan > -----Original Message----- > From: Ga=EBtan Rivet [mailto:gaetan.rivet@6wind.com] > Sent: Wednesday, August 30, 2017 5:25 PM > To: Matan Azrad > Cc: dev@dpdk.org; Raslan Darawsheh ; > stable@dpdk.org > Subject: Re: [PATCH] net/failsafe: fix exec parameter parsing error flow >=20 > On Wed, Aug 30, 2017 at 06:11:47AM +0000, Matan Azrad wrote: > > Hi Gaetan > > > > > -----Original Message----- > > > From: Ga=EBtan Rivet [mailto:gaetan.rivet@6wind.com] > > > Sent: Tuesday, August 29, 2017 7:34 PM > > > To: Matan Azrad > > > Cc: dev@dpdk.org; Raslan Darawsheh ; > > > 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. > > > >=20 > Actually I am unable to reproduce this bug. >=20 > Do you have a fail-safe command line that would showcase this behavior? testpmd -n 4 --vdev=3D"net_failsafe0,mac=3D00:15:5d:44:4b:17,exec(/root/df= ailsafe.sh,preferred,00:15:5d:44:4b:17),exec(/root/dfailsafe.sh,fallback,00= :15:5d:44:4b:17,0)" -w 0000:00:00.0 -- --burst=3D64 --mbcache=3D512 --por= tmask 0xf -i --txd=3D4096 --rxd=3D4096 --enable-scatter --nb-cores=3D7 = --rxq=3D2 --txq=3D2 --rss-udp --txqflags=3D0 just run the exec with non exists sh script. =20 >=20 > > > > 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 !=3D 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 poll= ing > process? > > I think in current code failsafe just continues normally and tries agai= n on > next polling time. > > Because of this code I thought that if error occurs we should poll it a= gain... > > >=20 > It depends whether the fail-safe has already been initialized or not. > During the initialization phase, any errors other than -ENODEV means that= it > must stop and force the user to look into it. >=20 > When initialization has finished, if polling errors occurs, the fail-safe= will try to > minimize service disruption to the potentially existing sub-devices. It t= hus > discards the error and will try again later. >=20 > > Can you please add it (the contract) in failsafe documentation for exec > parameter? > > Can you answer to the above question? > > > > 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 > > > > --- > > > > 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 =3D fs_parse_device(sdev, output); > > > > if (ret) { > > > > ERROR("Parsing device '%s' failed", output); > > > > + ret =3D -ENODEV; > > > > Remove the above line for probe function error report. > > > > > > goto ret_pclose; > > > > } > > > > ret_pclose: > > > > pclose_ret =3D pclose(fp); > > > > if (pclose_ret) { > > > > - pclose_ret =3D errno; > > > > + if (errno =3D=3D 0) > > > > + errno =3D -(pclose_ret =3D ret); > > > > + else > > > > + pclose_ret =3D errno; > > > > ERROR("pclose: %s", strerror(errno)); > > > > errno =3D old_err; > > > > return pclose_ret; > > > > -- > > > > 2.7.4 > > > > > > > > > > Best regards, > > > -- > > > Ga=EBtan Rivet > > > 6WIND > > > > Thanks, > > Matan Azrad >=20 > -- > Ga=EBtan Rivet > 6WIND Regards Matan Azrad