path: root/open_issues/glibc_tls_segment_tcbhead_t_dtv_offset.mdwn
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authorSamuel Thibault <>2015-02-18 00:58:35 +0100
committerSamuel Thibault <>2015-02-18 00:58:35 +0100
commit49a086299e047b18280457b654790ef4a2e5abfa (patch)
treec2b29e0734d560ce4f58c6945390650b5cac8a1b /open_issues/glibc_tls_segment_tcbhead_t_dtv_offset.mdwn
parente2b3602ea241cd0f6bc3db88bf055bee459028b6 (diff)
Revert "rename open_issues.mdwn to service_solahart_jakarta_selatan__082122541663.mdwn"
This reverts commit 95878586ec7611791f4001a4ee17abf943fae3c1.
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1 files changed, 28 insertions, 0 deletions
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+[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]]
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license
+is included in the section entitled [[GNU Free Documentation
+[[!tag open_issue_glibc]]
+IRC, unknown channel, unknown date.
+ <youpi> you can hardcode DTV_OFFSET as 4 for now
+ <youpi> it's the offset of the dtv field in the tcbhead_t structure from hurd/libpthread
+ <tschwinge> youpi: May very well be that I'm misunderstanding something, but wouldn't it rather be the offset of tcb in __pthread + the offset of dtv in tcbhead_t (which indeed is 4)?
+ <youpi> what you don't know is that DTV_OFFSET is not relative to __pthread, but to the tls segment
+ <tschwinge> Oh, aha. Thanks.
+ <youpi> and drepper abused the fact that in nptl __pthread appears at the start of the tls segment
+kFreeBSD, glibc:
+ ++#if 0
+ + DTV_OFFSET offsetof(struct pthread,
+ ++#else
+ ++DTV_OFFSET offsetof(struct _pthread_descr_struct,
+ ++#endif