https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98875
Bug ID: 98875
Summary: DWARF5 as default causes perf probe to hang
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: pc at us dot ibm.com
Target Milestone: ---
I sent this to gcc-patches, but realized I should open a bug report:
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The subject commit, 3804e937b0e252a7e42632fe6d9f898f1851a49c, causes a
failure in the test suite for the IBM Advance Toolchain. The test in
question uses "perf probe" to set a tracepoint at "main" in a newly built
(with GCC 11) binary of "/bin/ld". With the patch applied, the command
enters an infinte loop, calling libdw1 functions but making no progress.
The infinite loop can be found in the Linux kernel
tools/perf/utils/probe-finder.c:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/perf/util/probe-finder.c?h=v5.11-rc5#n1190
Reverting this patch permits the command to succeed.
--
$ grep VERSION= /etc/os-release
VERSION="15-SP2"
$ uname -r
5.3.18-22-default
$ perf --version
perf version 5.3.18
Top of the GCC tree used: ATSRC_PACKAGE_REV=eb9883c1312c
Reversion patch:
--
$ cat ~/projects/gcc/gcc/gcc-revert-dwarf-5.patch
diff --git a/gcc/common.opt b/gcc/common.opt
index a8a2b67a99d..7aff4ac6079 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -3179,7 +3179,7 @@ Common Driver JoinedOrMissing Negative(gdwarf-)
Generate debug information in default version of DWARF format.
gdwarf-
-Common Driver Joined UInteger Var(dwarf_version) Init(5) Negative(gstabs)
+Common Driver Joined UInteger Var(dwarf_version) Init(4) Negative(gstabs)
Generate debug information in DWARF v2 (or later) format.
gdwarf32
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Failing command:
$ perf probe -v -x /path/to/AT/at-next-15.0-0-alpha/bin/ld ldmain=main
