[dpdk-stable] [PATCH] net/failsafe: fix exec parameter parsing error flow

[dpdk-stable] [PATCH] net/failsafe: fix exec parameter parsing error flow

[Matan Azrad]

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.

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 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.

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;
 		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

Re: [dpdk-stable] [PATCH] net/failsafe: fix exec parameter parsing error flow

[Gaëtan Rivet]

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.

> 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.

> 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;
>  		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

Re: [dpdk-stable] [PATCH] net/failsafe: fix exec parameter parsing error flow

[Matan Azrad]

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

Re: [dpdk-stable] [PATCH] net/failsafe: fix exec parameter parsing error flow

[Gaëtan Rivet]

On Wed, Aug 30, 2017 at 06:11:47AM +0000, Matan Azrad wrote:
> 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.
> > 

Actually I am unable to reproduce this bug.

Do you have a fail-safe command line that would showcase this behavior?

> > > 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...
> 

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.

When initialization has finished, if polling errors occurs, the
fail-safe will try to minimize service disruption to the potentially
existing sub-devices. It thus discards the error and will try again
later.

> 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

-- 
Gaëtan Rivet
6WIND

Re: [dpdk-stable] [PATCH] net/failsafe: fix exec parameter parsing error flow

[Matan Azrad]

Hi Gaetan

> -----Original Message-----
> From: Gaëtan Rivet [mailto:gaetan.rivet@6wind.com]
> Sent: Wednesday, August 30, 2017 5:25 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
> 
> On Wed, Aug 30, 2017 at 06:11:47AM +0000, Matan Azrad wrote:
> > 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.
> > >
> 
> Actually I am unable to reproduce this bug.
> 
> Do you have a fail-safe command line that would showcase this behavior?

testpmd -n 4  --vdev="net_failsafe0,mac=00:15:5d:44:4b:17,exec(/root/dfailsafe.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=64 --mbcache=512 --portmask 0xf -i  --txd=4096 --rxd=4096  --enable-scatter  --nb-cores=7  --rxq=2 --txq=2 --rss-udp  --txqflags=0

just run the exec with non exists sh script.
 
> 
> > > > 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...
> >
> 
> 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.
> 
> When initialization has finished, if polling errors occurs, the fail-safe will try to
> minimize service disruption to the potentially existing sub-devices. It thus
> discards the error and will try again later.
> 
> > 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 <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
> 
> --
> Gaëtan Rivet
> 6WIND

Regards
Matan Azrad

[dpdk-stable] [PATCH] net/failsafe: fix errno set on command execution

[Gaetan Rivet]

This is unacceptable behavior.

Fixes: a0194d828100 ("net/failsafe: add flexible device definition")
Fixes: 35ffe4208140 ("net/failsafe: fix missing pclose after popen")
Cc: stable@dpdk.org

Reported-by: Matan Azrad <matan@mellanox.com>
Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
---
 drivers/net/failsafe/failsafe_args.c | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/drivers/net/failsafe/failsafe_args.c b/drivers/net/failsafe/failsafe_args.c
index 1f22416..cc29c5e 100644
--- a/drivers/net/failsafe/failsafe_args.c
+++ b/drivers/net/failsafe/failsafe_args.c
@@ -115,8 +115,7 @@ fs_execute_cmd(struct sub_device *sdev, char *cmdline)
 	/* store possible newline as well */
 	char output[DEVARGS_MAXLEN + 1];
 	size_t len;
-	int old_err;
-	int ret, pclose_ret;
+	int ret;
 
 	RTE_ASSERT(cmdline != NULL || sdev->cmdline != NULL);
 	if (sdev->cmdline == NULL) {
@@ -135,12 +134,10 @@ fs_execute_cmd(struct sub_device *sdev, char *cmdline)
 				sdev->cmdline[i] = ' ';
 	}
 	DEBUG("'%s'", sdev->cmdline);
-	old_err = errno;
 	fp = popen(sdev->cmdline, "r");
 	if (fp == NULL) {
-		ret = errno;
+		ret = -errno;
 		ERROR("popen: %s", strerror(errno));
-		errno = old_err;
 		return ret;
 	}
 	/* We only read one line */
@@ -155,18 +152,11 @@ fs_execute_cmd(struct sub_device *sdev, char *cmdline)
 		goto ret_pclose;
 	}
 	ret = fs_parse_device(sdev, output);
-	if (ret) {
+	if (ret)
 		ERROR("Parsing device '%s' failed", output);
-		goto ret_pclose;
-	}
 ret_pclose:
-	pclose_ret = pclose(fp);
-	if (pclose_ret) {
-		pclose_ret = errno;
+	if (pclose(fp) == -1)
 		ERROR("pclose: %s", strerror(errno));
-		errno = old_err;
-		return pclose_ret;
-	}
 	return ret;
 }
 
-- 
2.1.4

Re: [dpdk-stable] [PATCH] net/failsafe: fix errno set on command execution

[Ferruh Yigit]

On 8/30/2017 4:59 PM, Gaetan Rivet wrote:
> This is unacceptable behavior.
> 
> Fixes: a0194d828100 ("net/failsafe: add flexible device definition")
> Fixes: 35ffe4208140 ("net/failsafe: fix missing pclose after popen")
> Cc: stable@dpdk.org
> 
> Reported-by: Matan Azrad <matan@mellanox.com>
> Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>

Applied to dpdk-next-net/master, thanks.