[Bug libc/22280] New: relocations not performed on failed dlopen

["woodard at redhat dot com" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=22280

            Bug ID: 22280
           Summary: relocations not performed on failed dlopen
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
          Assignee: unassigned at sourceware dot org
          Reporter: woodard at redhat dot com
                CC: drepper.fsp at gmail dot com
  Target Milestone: ---

Created attachment 10521
  --> https://sourceware.org/bugzilla/attachment.cgi?id=10521&action=edit
reproducer

The runtime linker fails to perform relocation on a shared library brought in
as a dependency which is marked NODELETE even though it isn't deleted. This
causes problems when a subsequent library also tries to make use of the same
library.

[ben@Mustang dl-bug]$ make all
cc -g   -c -o main.o main.c
cc -g -o main main.o -ldl
cc -g -c -fpic a.c
cc -g -c -fpic d.c
cc -g -fpic -shared -Wl,-z,nodelete -o libd.so d.o
cc -g -c -fpic e.c
cc -g -fpic -shared -o libe.so e.o
cc -g -fpic -shared -o liba.so a.o -L. -ld -le
cc -g -c -fpic b.c
cc -g -fpic -shared -o libb.so b.o -L. -ld
[ben@Mustang dl-bug]$ make run
LD_LIBRARY_PATH=. ./main
d_fn x=12
inside b_fn
rm libe.so
LD_LIBRARY_PATH=. ./main
Could not open liba.so - libe.so: cannot open shared object file: No such file
or directory
make: *** [Makefile:38: run] Segmentation fault (core dumped)

Note that libd.so is marked NODELETE
So when main dlopen's liba.so which needs on libd.so and libe.so because
libe.so is missing, the load of liba.so fails. This is expected. However, when
libb.so is loaded which also needs libd.so the application crashes because the
relocations haven't been done.

[ben@Mustang dl-bug]$ LD_LIBRARY_PATH=. LD_DEBUG=reloc,files ./main 2> foo
d_fn x=12
inside b_fn
[ben@Mustang dl-bug]$ egrep file\|reloc foo
     10901:     file=libdl.so.2 [0];  needed by ./main [0]
     10901:     file=libdl.so.2 [0];  generating link map
     10901:     file=libc.so.6 [0];  needed by ./main [0]
     10901:     file=libc.so.6 [0];  generating link map
     10901:     relocation processing: /lib64/libc.so.6
     10901:     relocation processing: /lib64/libdl.so.2
     10901:     relocation processing: ./main (lazy)
     10901:     relocation processing: /lib64/ld-linux-x86-64.so.2
     10901:     file=liba.so [0];  dynamically loaded by ./main [0]
     10901:     file=liba.so [0];  generating link map
     10901:     file=libd.so [0];  needed by ./liba.so [0]
     10901:     file=libd.so [0];  generating link map
     10901:     file=libe.so [0];  needed by ./liba.so [0]
     10901:     file=libe.so [0];  generating link map
     10901:     relocation processing: ./libe.so
     10901:     relocation processing: ./libd.so
     10901:     relocation processing: ./liba.so
     10901:     opening file=./liba.so [0]; direct_opencount=1
     10901:     file=libb.so [0];  dynamically loaded by ./main [0]
     10901:     file=libb.so [0];  generating link map
     10901:     relocation processing: ./libb.so
     10901:     opening file=./libb.so [0]; direct_opencount=1

vs.

[ben@Mustang dl-bug]$ rm libe.so
[ben@Mustang dl-bug]$ LD_LIBRARY_PATH=. LD_DEBUG=reloc,files ./main 2> foo
Segmentation fault (core dumped)
[ben@Mustang dl-bug]$ egrep file\|reloc foo
     10965:     file=libdl.so.2 [0];  needed by ./main [0]
     10965:     file=libdl.so.2 [0];  generating link map
     10965:     file=libc.so.6 [0];  needed by ./main [0]
     10965:     file=libc.so.6 [0];  generating link map
     10965:     relocation processing: /lib64/libc.so.6
     10965:     relocation processing: /lib64/libdl.so.2
     10965:     relocation processing: ./main (lazy)
     10965:     relocation processing: /lib64/ld-linux-x86-64.so.2
     10965:     file=liba.so [0];  dynamically loaded by ./main [0]
     10965:     file=liba.so [0];  generating link map
     10965:     file=libd.so [0];  needed by ./liba.so [0]
     10965:     file=libd.so [0];  generating link map
     10965:     file=libe.so [0];  needed by ./liba.so [0]
     10965:     file=./liba.so [0];  destroying link map
Could not open liba.so - libe.so: cannot open shared object file: No such file
or directory
     10965:     file=libb.so [0];  dynamically loaded by ./main [0]
     10965:     file=libb.so [0];  generating link map
     10965:     relocation processing: ./libb.so

Note on the failing case the relocations are never done on libd.so

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