From: Lancelot SIX Date: Wed, 31 May 2023 11:23:05 +0000 (+0100) Subject: gdb/corelow.c: avoid repeated warnings in build_file_mappings X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=0ad504dd4645153fc7c6e8e6a5979b0f79830341;p=binutils-gdb.git gdb/corelow.c: avoid repeated warnings in build_file_mappings When GDB opens a coredump it tries to locate and then open all files which were mapped in the process. If a file is found but cannot be opened with BFD (bfd_open / bfd_check_format fails), then a warning is printed to the user. If the same file was mapped multiple times in the process's address space, the warning is printed once for each time the file was mapped. I find this un-necessarily noisy. This patch makes it so the warning message is printed only once per file. There was a comment in the code assuming that if the file was found on the system, opening it (bfd_open + bfd_check_format) should always succeed. A recent change in BFD (014a602b86f "Don't optimise bfd_seek to same position") showed that this assumption is not valid. For example, it is possible to have a core dump of a process which had mmaped an IO page from a DRI render node (/dev/dri/runderD$NUM). In such case the core dump does contain the information that portions of this special file were mapped in the host process, but trying to seek to position 0 will fail, making bfd_check_format fail. This patch removes this comment. Reviewed-By: John Baldwin Approved-By: Andrew Burgess --- diff --git a/gdb/corelow.c b/gdb/corelow.c index 54def4198bc..0b51428f77c 100644 --- a/gdb/corelow.c +++ b/gdb/corelow.c @@ -263,18 +263,11 @@ core_target::build_file_mappings () if (bfd == nullptr || !bfd_check_format (bfd, bfd_object)) { m_core_unavailable_mappings.emplace_back (start, end - start); - /* If we get here, there's a good chance that it's due to - an internal error. We issue a warning instead of an - internal error because of the possibility that the - file was removed in between checking for its - existence during the expansion in exec_file_find() - and the calls to bfd_openr() / bfd_check_format(). - Output both the path from the core file note along - with its expansion to make debugging this problem - easier. */ - warning (_("Can't open file %s which was expanded to %s " - "during file-backed mapping note processing"), - filename, expanded_fname.get ()); + if (unavailable_paths.insert (filename).second) + warning (_("Can't open file %s which was expanded to %s " + "during file-backed mapping note processing"), + filename, expanded_fname.get ()); + if (bfd != nullptr) bfd_close (bfd); return;