[ was: Re: [backtrace] Avoid segfault ] On 27-01-19 22:53, Ian Lance Taylor wrote: > On Sun, Jan 27, 2019 at 1:16 PM Tom de Vries <tdevr...@suse.de> wrote: >> >> On 25-01-19 18:15, Nathan Sidwell wrote: >>> On 1/25/19 5:28 AM, Tom de Vries wrote: >>>> >>>> This patch fixes it by passing "" instead of NULL, in the call to >>>> elf_add at line 3083 (for .gnu_debugaltlink), not the call to elf_add at >>>> line 3044 (for .gnu_debuglink) mentioned above. >>>> >>>> Nathan, does this fix the problem for you? If not, can you provide a >>>> reproducer, or give a hint on how one could be constructed? >>> >>> I still hit the problem, and am installing this as sufficiently obvious. >>> I'm on a fedora system debugging pr88995. The debuglink_name is >>> "../../.dwz/isl-0.16.1-7.fc29.x86_64" >>> >> >> I've managed to reproduce this segfault instance by adding a test-case >> that uses both build-id and dwz. >> >> OK for trunk? > >> +elf_for_test.c: elf.c >> + PWD=$$(pwd -P); \ >> + BUILD_ID_DIR="usr/lib/debug/.build-id/"; \ >> + SEARCH='#define SYSTEM_BUILD_ID_DIR'; \ >> + REPLACE="#define SYSTEM_BUILD_ID_DIR \"$$PWD/$$BUILD_ID_DIR\""; \ >> + $(SED) "s%^$$SEARCH.*\$$%$$REPLACE%" \ >> + $< \ >> + > $@ > > You need to use a temporary file, such as $@.tmp, for the final sed > command, followed by a mv to $@. Otherwise a failure in the sed will > leave what appears to be an up to date file.
I noticed the same problem in the xcoff_%.c pattern rule. OK for trunk? Thanks, - Tom
[libbacktrace] Fix and simplify xcoff_%.c pattern rule When generating xcoff_%.c, the last command is a sed command. In case of a sed failure, this will leave an incomplete file, which will appear as up to date to make, so consequently it will not be regenerated. Fix this by sedding into a temporary file instead. Also, use $< to access the prerequisite xcoff.c, instead of spelling out the file name once more. 2019-01-28 Tom de Vries <tdevr...@suse.de> * Makefile.am (xcoff_%.c): Generate sed result into temporary file. Use $< to access prerequisite. * Makefile.in: Regenerate. --- libbacktrace/Makefile.am | 5 +++-- libbacktrace/Makefile.in | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/libbacktrace/Makefile.am b/libbacktrace/Makefile.am index 997a535dff4..0d5b3193e25 100644 --- a/libbacktrace/Makefile.am +++ b/libbacktrace/Makefile.am @@ -108,8 +108,9 @@ xcoff_%.c: xcoff.c REPLACE='#undef BACKTRACE_XCOFF_SIZE\ #define BACKTRACE_XCOFF_SIZE'; \ $(SED) "s/^$$SEARCH\$$/$$REPLACE $*/" \ - $(srcdir)/xcoff.c \ - > $@ + $< \ + > $@.tmp + mv $@.tmp $@ test_elf_SOURCES = test_format.c testlib.c test_elf_LDADD = libbacktrace_noformat.la elf.lo diff --git a/libbacktrace/Makefile.in b/libbacktrace/Makefile.in index f04577066f8..b25ac92aeda 100644 --- a/libbacktrace/Makefile.in +++ b/libbacktrace/Makefile.in @@ -1754,8 +1754,9 @@ uninstall-am: @NATIVE_TRUE@ REPLACE='#undef BACKTRACE_XCOFF_SIZE\ @NATIVE_TRUE@ #define BACKTRACE_XCOFF_SIZE'; \ @NATIVE_TRUE@ $(SED) "s/^$$SEARCH\$$/$$REPLACE $*/" \ -@NATIVE_TRUE@ $(srcdir)/xcoff.c \ -@NATIVE_TRUE@ > $@ +@NATIVE_TRUE@ $< \ +@NATIVE_TRUE@ > $@.tmp +@NATIVE_TRUE@ mv $@.tmp $@ @NATIVE_TRUE@instrumented_alloc.lo: alloc.c
