RE: [PATCH] gdb: don't abort shared library reload when one library fails to open

["Rohr, Stephan" <stephan.rohr@intel.com>]

Hi Eduard,

please see my feedback below:

thanks
stephan

> -----Original Message-----
> From: Eduard-Petru Jipa <ejipa@undo.io>
> Sent: Wednesday, 7 October 2026 13:19
> To: gdb-patches@sourceware.org
> Cc: Eduard Jipa <ejipa@undo.io>
> Subject: [PATCH] gdb: don't abort shared library reload when one library fails
> to open
> 
> From: Eduard Jipa <ejipa@undo.io>
> 
> When the set of shared libraries is reloaded, for example after
> 'set sysroot' or 'set solib-search-path', reload_shared_libraries_1
> calls solib_ops::bfd_open for each library in turn.  This can throw an
> error, for example if the file found is not in executable format, or
> its architecture is not compatible with the target.
> 
> Nothing in the loop catches that error, so a single bad library stops
> the whole reload.  Any libraries after it in the list are not reloaded,
> and the error propagates out of the command that triggered the reload.
> 
> Catch the error, print it as a warning, and carry on with the rest of
> the libraries.  This matches what is already done for errors from
> solib_map_sections later in the same loop.  The library that failed
> to open is handled as if it had not been found.
> 
> Add a test that builds a sysroot in which the first of two libraries
> is not a valid object file, and checks that the second library is
> still reloaded from the new sysroot after 'set sysroot'.
> 
> Tested on x86_64-linux with no regressions.
> ---
>  gdb/solib.c                                   | 13 ++-
>  .../gdb.base/solib-reload-error-lib.c         | 25 ++++++
>  gdb/testsuite/gdb.base/solib-reload-error.c   | 25 ++++++
>  gdb/testsuite/gdb.base/solib-reload-error.exp | 81 +++++++++++++++++++
>  4 files changed, 143 insertions(+), 1 deletion(-)
>  create mode 100644 gdb/testsuite/gdb.base/solib-reload-error-lib.c
>  create mode 100644 gdb/testsuite/gdb.base/solib-reload-error.c
>  create mode 100644 gdb/testsuite/gdb.base/solib-reload-error.exp
> 
> diff --git a/gdb/solib.c b/gdb/solib.c
> index 7ea3084bf48..ad964e0afe9 100644
> --- a/gdb/solib.c
> +++ b/gdb/solib.c
> @@ -1463,7 +1463,18 @@ reload_shared_libraries_1 (int from_tty)
>        gdb::unique_xmalloc_ptr<char> filename
>  	= gdb_rl_tilde_expand (so.original_name.c_str ());
> 
> -      gdb_bfd_ref_ptr abfd = so.ops ().bfd_open (filename.get ());
> +      gdb_bfd_ref_ptr abfd;
> +      try
> +	{
> +	  abfd = so.ops ().bfd_open (filename.get ());
> +	}
> +      catch (const gdb_exception_error &e)
> +	{
> +	  exception_fprintf (gdb_stderr, e,
> +			     _("Error while opening shared library `%ps':\n"),
> +			     styled_string (file_name_style.style (),
> +					    filename.get ()));

I think this prints the filename twice.  I tried it locally, e.g.,

Error while opening shared library [..]/gdb/testsuite/outputs/gdb.base/solib-reload-error/solib-reload-error-lib1.so':
`[..]/gdb/testsuite/outputs/gdb.base/solib-reload-error/sysroot/[..] \
  /gdb/testsuite/outputs/gdb.base/solib-reload-error/solib-reload-error-lib1.so': \
  not in executable format: file format not recognized

I think it would be nice to simply print

Error while opening shared library <path to lib>: <error>.

Would that be possible?  If not, we could drop the first mention of the failing lib?

Also, the commit message mentions "Catch the error, print it as warning [..]" but you use
"exception_printf" here.  Either reword the commit message or use "warning ()".

> +	}
>        if (abfd != NULL)
>  	found_pathname = bfd_get_filename (abfd.get ());
> 
> diff --git a/gdb/testsuite/gdb.base/solib-reload-error-lib.c
> b/gdb/testsuite/gdb.base/solib-reload-error-lib.c
> new file mode 100644
> index 00000000000..7aaa13fd697
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/solib-reload-error-lib.c
> @@ -0,0 +1,25 @@
> +/* This test program is part of GDB, the GNU debugger.
> +
> +   Copyright 2026 Free Software Foundation, Inc.
> +
> +   This program is free software; you can redistribute it and/or modify
> +   it under the terms of the GNU General Public License as published by
> +   the Free Software Foundation; either version 3 of the License, or
> +   (at your option) any later version.
> +
> +   This program is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +   GNU General Public License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
> +
> +/* This file is compiled twice, with LIB_FUNC defined to a different
> +   name each time.  */
> +
> +int
> +LIB_FUNC (void)
> +{
> +  return 0;
> +}
> diff --git a/gdb/testsuite/gdb.base/solib-reload-error.c
> b/gdb/testsuite/gdb.base/solib-reload-error.c
> new file mode 100644
> index 00000000000..465cf7e82e6
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/solib-reload-error.c
> @@ -0,0 +1,25 @@
> +/* This test program is part of GDB, the GNU debugger.
> +
> +   Copyright 2026 Free Software Foundation, Inc.
> +
> +   This program is free software; you can redistribute it and/or modify
> +   it under the terms of the GNU General Public License as published by
> +   the Free Software Foundation; either version 3 of the License, or
> +   (at your option) any later version.
> +
> +   This program is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +   GNU General Public License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
> +
> +extern int lib1_func (void);
> +extern int lib2_func (void);
> +
> +int
> +main (void)
> +{
> +  return lib1_func () + lib2_func ();
> +}
> diff --git a/gdb/testsuite/gdb.base/solib-reload-error.exp
> b/gdb/testsuite/gdb.base/solib-reload-error.exp
> new file mode 100644
> index 00000000000..adbafde1fbe
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/solib-reload-error.exp
> @@ -0,0 +1,81 @@
> +# Copyright 2026 Free Software Foundation, Inc.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +# Check that an error opening one shared library while reloading
> +# shared libraries (in this case, triggered by 'set sysroot') does not
> +# stop GDB from reloading the shared libraries that come after it.
> +
> +require allow_shlib_tests
> +require {!is_remote host}
> +
> +standard_testfile .c -lib.c
> +
> +set lib1 [standard_output_file ${testfile}-lib1.so]
> +set lib2 [standard_output_file ${testfile}-lib2.so]
> +
> +if { [gdb_compile_shlib $srcdir/$subdir/$srcfile2 $lib1 \
> +	  {debug additional_flags=-DLIB_FUNC=lib1_func}] != ""
> +     || [gdb_compile_shlib $srcdir/$subdir/$srcfile2 $lib2 \
> +	     {debug additional_flags=-DLIB_FUNC=lib2_func}] != "" } {
> +    untested "failed to compile shared libraries"
> +    return
> +}
> +
> +# Link against lib1 first, so that it is ahead of lib2 in the list of
> +# shared libraries that GDB reloads.
> +if { [prepare_for_testing "failed to prepare" $testfile $srcfile \
> +	  [list debug shlib=$lib1 shlib=$lib2]] } {
> +    return
> +}
> +
> +gdb_load_shlib $lib1
> +gdb_load_shlib $lib2
> +
> +if { ![runto_main] } {
> +    return
> +}
> +
> +# The rest of the test relies on lib1 being reloaded before lib2.
> +if { [gdb_test "info sharedlibrary" \
> +	  "[string_to_regexp $lib1]\r\n.*[string_to_regexp $lib2]\r\n.*" \
> +	  "lib1 is ahead of lib2 in the list"] != 0 } {
> +    return
> +}
> +
> +# Build a sysroot in which lib1 is not a valid object file, but lib2
> +# is a good copy of the real library.
> +set sysroot [standard_output_file sysroot]
> +set sysroot_lib1 $sysroot$lib1
> +set sysroot_lib2 $sysroot$lib2
> +file delete -force $sysroot
> +file mkdir [file dirname $sysroot_lib1]
> +set fd [open $sysroot_lib1 w]
> +puts $fd "This is not an object file."
> +close $fd
> +file copy $lib2 $sysroot_lib2
> +
> +# Changing the sysroot reloads every shared library.  Opening lib1
> +# fails, and GDB should report that and carry on.
> +gdb_test "set sysroot $sysroot" \
> +    "Error while opening shared library `[string_to_regexp $lib1]':\r\n.*not in
> executable format.*" \
> +    "set sysroot with bad lib1"
> +
> +# lib2 comes after lib1 in the list, so it is only reloaded from the
> +# new sysroot if the error opening lib1 did not stop the reload.
> +gdb_test "info sharedlibrary" \
> +    "\r\n$hex\[ \t\]+$hex\[ \t\]+Yes\[^\r\n\]*[string_to_regexp

Could you also cover lib1, i.e., ensure it is not loaded?

> $sysroot_lib2]\r\n.*" \
> +    "lib2 is reloaded from the new sysroot"
> +
> +gdb_test "info symbol lib2_func" "lib2_func in section \\.text of
> [string_to_regexp $sysroot_lib2]"
> --
> 2.43.0

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