[8u] RFR for JDK-8157548: JVM crashes sometimes while starting

[Shafi Ahmad]

Thanks David for the review.

Regards,
Shafi

> -----Original Message-----
> From: David Holmes
> Sent: Monday, September 19, 2016 12:33 PM
> To: Shafi Ahmad; hotspot-dev at openjdk.java.net
> Subject: Re: [8u] RFR for JDK-8157548: JVM crashes sometimes while starting
> 
> Hi Shafi,
> 
> This looks okay to me.
> 
> Thanks,
> David
> 
> On 19/09/2016 3:14 PM, Shafi Ahmad wrote:
> > Hi,
> >
> > Please review the small code change for bug: "JDK-8157548: JVM crashes
> sometimes while starting" on jdk8u-dev
> >
> > Summary:
> > int strncmp(const char *s1, const char *s2, size_t n);
> >
> > s1 = "abcdefgh" // Assume this is not null terminated string.
> > s2 = "abcdefghijk"
> > n = 10
> >
> > In case if s1 is not null terminated then for above input strncmp may crash.
> >
> > In expression marked as (B) parsed_name->bytes() returns base address
> of non-null terminated string buffer.
> >
> > +  size_t pkglen = strlen(pkg);
> >    if (!HAS_PENDING_EXCEPTION &&
> >        !class_loader.is_null() &&
> >        parsed_name != NULL &&
> > -      !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
> > +      parsed_name->utf8_length() >= (int)pkglen &&                             // -------
> ----------------------- (A)
> > +      !strncmp((const char*)parsed_name->bytes(), pkg, pkglen)) { //--------
> ---------------------- (B)
> >
> > Adding expression marked as (A) avoid the above similar input  scenario.
> >
> > Webrev: http://cr.openjdk.java.net/~shshahma/8157548/webrev.00/
> > Jdk8 bug: https://bugs.openjdk.java.net/browse/JDK-8157548
> >
> > Test:  Run jprt
> >
> > Note: Thanks to Ioi for providing the code change.
> >
> > Regards,
> > Shafi
> >