Date: Mon, 16 Jan 2006 10:10:06 GMT From: Doug Rabson <dfr@rabson.org> To: freebsd-ia64@FreeBSD.org Subject: Re: ia64/91846: TLS: malloc(3) exposes DTLS bug in non-threaded applications Message-ID: <200601161010.k0GAA6IV077853@freefall.freebsd.org>
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The following reply was made to PR ia64/91846; it has been noted by GNATS. From: Doug Rabson <dfr@rabson.org> To: freebsd-ia64@freebsd.org Cc: Marcel Moolenaar <marcel@xcllnt.net>, freebsd-gnats-submit@freebsd.org Subject: Re: ia64/91846: TLS: malloc(3) exposes DTLS bug in non-threaded applications Date: Mon, 16 Jan 2006 10:09:41 +0000 On Monday 16 January 2006 00:22, Marcel Moolenaar wrote: > >Number: 91846 > >Category: ia64 > >Synopsis: TLS: malloc(3) exposes DTLS bug in non-threaded > > applications Confidential: no > >Severity: serious > >Priority: medium > >Responsible: freebsd-ia64 > >State: open > >Quarter: > >Keywords: > >Date-Required: > >Class: sw-bug > >Submitter-Id: current-users > >Arrival-Date: Mon Jan 16 00:30:07 GMT 2006 > >Closed-Date: > >Last-Modified: > >Originator: Marcel Moolenaar > >Release: 7-CURRENT > >Organization: > >Environment: > > FreeBSD bigsur.pn.xcllnt.net 7.0-CURRENT FreeBSD 7.0-CURRENT #1: Fri > Jan 13 16:26:27 PST 2006 > marcel@bigsur.pn.xcllnt.net:/usr/obj/nfs/freebsd/7.x/src/sys/BIGSUR > ia64 > > >Description: > > When NO_TLS is *not* defined in src/lib/libc/stdlib/malloc.c on ia64, > then a SIGSEGV will result due to arenas_map being thread-local and > it being referenced in choose_arena(). That reference causes a > thread-local relocation to end up in tls_get_addr_common() in > src/libexec/rtld-elf/rtld.c for which the dtvp argument is NULL. This > pretty much means that __tls_get_addr() on ia64 does the wrong thing. > In this case it assumes that r13 (aka TP) is non-NULL in all cases, > which is false for non-threaded applications. I don't understand this. Any dynamic application (threaded or non-threaded) should end up calling .../ia64/reloc.c:allocate_initial_tls() which sets r13 to point at the TLS block for the main thread (or only thread for non-threaded).
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