Re: [dpdk-dev] [PATCH v7] linuxapp, eal: Fix the memory leak issue of logid

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> -----Original Message-----
> From: Aaron Conole [mailto:aconole@redhat.com]
> Sent: Tuesday, September 11, 2018 2:47 PM
> To: Yang, Ziye <ziye.yang@intel.com>
> Cc: dev@dpdk.org; Ananyev, Konstantin <konstantin.ananyev@intel.com>; Ziye Yang <optimistyzy@gmail.com>
> Subject: Re: [dpdk-dev] [PATCH v7] linuxapp, eal: Fix the memory leak issue of logid
> 
> Ziye Yang <ziye.yang@intel.com> writes:
> 
> > From: Ziye Yang <optimistyzy@gmail.com>
> >
> > This patch is used to fix the memory leak issue of logid.
> > We use the ASAN test in SPDK when intergrating DPDK and
> > find this memory leak issue.
> >
> > By the way, we also fix several missed function call of
> > rte_atomic32_clear.
> 
> This part I don't understand.  It should be a separate proposal.
> 
> > Signed-off-by: Ziye Yang <ziye.yang@intel.com>
> > ---
> >  lib/librte_eal/linuxapp/eal/eal.c | 11 +++++++----
> >  1 file changed, 7 insertions(+), 4 deletions(-)
> >
> > diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
> > index e59ac65..a5129e5 100644
> > --- a/lib/librte_eal/linuxapp/eal/eal.c
> > +++ b/lib/librte_eal/linuxapp/eal/eal.c
> > @@ -793,7 +793,8 @@ static void rte_eal_init_alert(const char *msg)
> >  	int i, fctret, ret;
> >  	pthread_t thread_id;
> >  	static rte_atomic32_t run_once = RTE_ATOMIC32_INIT(0);
> > -	const char *logid;
> > +	const char *p;
> > +	static char logid[PATH_MAX];
> 
> On a linux system, PATH_MAX is 4096, but an argument may be
> MAX_ARG_STRLEN which is significantly higher.

But we only interested here in 'basename(argv[0])'.
Surely it shouldn't be bigger than PATH_MAX unless something is terribly wrong here.

> 
> Have you thought about an alternative where you keep the strdup and add
> an atexit() handler to do the free?  Otherwise, you'll need to add code
> to check the string length as well and enforce some kind of size
> restriction.

snprintf() below will do a safe truncation for us.

> 
> >  	char cpuset[RTE_CPU_AFFINITY_STR_LEN];
> >  	char thread_name[RTE_MAX_THREAD_NAME_LEN];
> >
> > @@ -810,9 +811,8 @@ static void rte_eal_init_alert(const char *msg)
> >  		return -1;
> >  	}
> >
> > -	logid = strrchr(argv[0], '/');
> > -	logid = strdup(logid ? logid + 1: argv[0]);
> > -
> > +	p = strrchr(argv[0], '/');
> > +	snprintf(logid, sizeof(logid), "%s", (p ? p + 1 : argv[0]));
> >  	thread_id = pthread_self();
> >
> >  	eal_reset_internal_config(&internal_config);
> > @@ -823,6 +823,7 @@ static void rte_eal_init_alert(const char *msg)
> >  	if (rte_eal_cpu_init() < 0) {
> >  		rte_eal_init_alert("Cannot detect lcores.");
> >  		rte_errno = ENOTSUP;
> > +		rte_atomic32_clear(&run_once);
> 
> This is not recoverable.  No amount of retry will allow the user to
> re-init the eal - the hardware isn't supported.  Why clear the run_once
> flag?
> 
> >  		return -1;
> >  	}
> >
> > @@ -851,6 +852,7 @@ static void rte_eal_init_alert(const char *msg)
> >
> >  	if (rte_eal_intr_init() < 0) {
> >  		rte_eal_init_alert("Cannot init interrupt-handling thread\n");
> > +		rte_atomic32_clear(&run_once);
> 
> Arguable whether or not this is recoverable.  IIRC, the eal_intr_init
> spawns a thread - if it fails to spawn the likelihood is the process
> won't be able to continue.
> 
> >  		return -1;
> >  	}
> >
> > @@ -861,6 +863,7 @@ static void rte_eal_init_alert(const char *msg)
> >  		rte_eal_init_alert("failed to init mp channel\n");
> >  		if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
> >  			rte_errno = EFAULT;
> > +			rte_atomic32_clear(&run_once);
> 
> This is also not recoverable.  Why clear the run_once flag?
> 
> >  			return -1;
> >  		}
> >  	}