RFR(M): 8141529: Fix handling of _JAVA_SR_SIGNUM (original) (raw)

Lindenmaier, Goetz goetz.lindenmaier at sap.com
Thu Nov 12 08:36:20 UTC 2015

OK I'll change it to NSIG. That's used in other places in os_linux, too. So it's really more consistent.

Best regards, Goetz

-----Original Message----- From: Dmitry Samersoff [mailto:dmitry.samersoff at oracle.com] Sent: Donnerstag, 12. November 2015 09:22 To: David Holmes; Lindenmaier, Goetz; hotspot-runtime- dev at openjdk.java.net; serviceability-dev Subject: Re: RFR(M): 8141529: Fix handling of JAVASRSIGNUM

David, I think it's better to use NSIG (without underscore) defined in signal.h -Dmitry

On 2015-11-12 10:35, David Holmes wrote: > Hi Goetz, > > Adding in serviceability-dev > > On 9/11/2015 6:22 PM, Lindenmaier, Goetz wrote: >> Hi, >> >> The environment variable JAVASRSIGNUM can be set to a signal number >> do be used by the JVM's suspend/resume mechanism. >> >> If set, a signal handler is installed and the current signal handler >> is saved to an array. >> On linux, this array had size MAXSIGNUM=32, and JAVASRSIGNUM was >> allowed >> to range up to NSIG=65. This could cause memory corruption. >> >> Further, in jsig.c, an unsinged int is used to set a bit for signals. >> This also >> is too small, as only 32 signals can be supported. Further, the >> signals are mapped >> wrong to these bits. '0' is not a valid signal, but '32' was. 1<<32_ _>> happens to map to >> zero, so the signal could be stored, but this probably was not >> intended that way. >> >> This change increases MAXSIGNUM to 65 on linux, and to 64 on aix. It >> introduces >> proper checking of the signal read from the env var, and issues a >> warning if it >> does not use the signal set. It adapts the data types in jisig.c >> properly. >> >> Please review this change. I please need a sponsor. >> http://cr.openjdk.java.net/~goetz/webrevs/8141529-NSIG/webrev.00 > > This all sounds very good to me. (I must find out why Solaris is not > involved here :) ). > > On Linux you didn't add the bounds check to os::Linux::setoursigflags. > > I'm also wondering about documenting where we are determining the > maximum from? Is it simply NSIG on some/all distributions? And I see > NSIG is supposed to be the biggest signal number + one. Also linux > defines NSIG = NSIG so which should we be using? > > Thanks, > David > >> Best regards, >> Goetz. >> -- Dmitry Samersoff Oracle Java development team, Saint Petersburg, Russia * I would love to change the world, but they won't give me the sources.

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