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* [Bug dynamic-link/15097] New: The loader should avoid writing over already-valid relocations @ 2013-02-04 22:18 sourceware.org at plagman dot net 2013-02-05 11:16 ` [Bug dynamic-link/15097] " schwab@linux-m68k.org ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: sourceware.org at plagman dot net @ 2013-02-04 22:18 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=15097 Bug #: 15097 Summary: The loader should avoid writing over already-valid relocations Product: glibc Version: unspecified Status: NEW Severity: normal Priority: P2 Component: dynamic-link AssignedTo: unassigned@sourceware.org ReportedBy: sourceware.org@plagman.net Classification: Unclassified When pre-relocating a shared object to a certain base address using `prelink -r` (and successfully loading it there), the loader will still compute and overwrite all relocations. This marks the pages of the mapping dirty, triggers copy-on-write and ends up committing private memory to all processes mapping that shared object that could otherwise have been cleanly shared. If the loader did a comparison between the relocation it computed and the existing contents of the destination before performing the write, this would be avoided. I suspect only having such a check for RELATIVE relocations would be sufficient in practice, but in theory applying it to all types of relocations could exhibit memory benefits with a small runtime cost. See this email exchange for more details about the usecase, and the attached example patch: http://lists.freedesktop.org/archives/wayland-devel/2012-March/002798.html http://lists.freedesktop.org/archives/wayland-devel/attachments/20120327/a8bedd3f/attachment.patch -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug dynamic-link/15097] The loader should avoid writing over already-valid relocations 2013-02-04 22:18 [Bug dynamic-link/15097] New: The loader should avoid writing over already-valid relocations sourceware.org at plagman dot net @ 2013-02-05 11:16 ` schwab@linux-m68k.org 2014-06-13 18:55 ` fweimer at redhat dot com 2024-05-07 11:42 ` fweimer at redhat dot com 2 siblings, 0 replies; 4+ messages in thread From: schwab@linux-m68k.org @ 2013-02-05 11:16 UTC (permalink / raw) To: glibc-bugs http://sourceware.org/bugzilla/show_bug.cgi?id=15097 --- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> 2013-02-05 11:16:31 UTC --- Perhaps it is sufficient to check for l_addr == 0. -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug dynamic-link/15097] The loader should avoid writing over already-valid relocations 2013-02-04 22:18 [Bug dynamic-link/15097] New: The loader should avoid writing over already-valid relocations sourceware.org at plagman dot net 2013-02-05 11:16 ` [Bug dynamic-link/15097] " schwab@linux-m68k.org @ 2014-06-13 18:55 ` fweimer at redhat dot com 2024-05-07 11:42 ` fweimer at redhat dot com 2 siblings, 0 replies; 4+ messages in thread From: fweimer at redhat dot com @ 2014-06-13 18:55 UTC (permalink / raw) To: glibc-bugs https://sourceware.org/bugzilla/show_bug.cgi?id=15097 Florian Weimer <fweimer at redhat dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |fweimer at redhat dot com Flags| |security- -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug dynamic-link/15097] The loader should avoid writing over already-valid relocations 2013-02-04 22:18 [Bug dynamic-link/15097] New: The loader should avoid writing over already-valid relocations sourceware.org at plagman dot net 2013-02-05 11:16 ` [Bug dynamic-link/15097] " schwab@linux-m68k.org 2014-06-13 18:55 ` fweimer at redhat dot com @ 2024-05-07 11:42 ` fweimer at redhat dot com 2 siblings, 0 replies; 4+ messages in thread From: fweimer at redhat dot com @ 2024-05-07 11:42 UTC (permalink / raw) To: glibc-bugs https://sourceware.org/bugzilla/show_bug.cgi?id=15097 Florian Weimer <fweimer at redhat dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |WONTFIX Status|NEW |RESOLVED --- Comment #2 from Florian Weimer <fweimer at redhat dot com> --- We have removed prelink support, so I do not think this is an issue anymore. -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-05-07 11:42 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2013-02-04 22:18 [Bug dynamic-link/15097] New: The loader should avoid writing over already-valid relocations sourceware.org at plagman dot net 2013-02-05 11:16 ` [Bug dynamic-link/15097] " schwab@linux-m68k.org 2014-06-13 18:55 ` fweimer at redhat dot com 2024-05-07 11:42 ` fweimer at redhat dot com
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