Hi, This issue was noticed through grep 3.5 and 3.6’s stack-overflow test failing [0] on SPARC on Gentoo GNU/Linux.
Following Paul Eggert’s instructions in that bug to test gnulib’s c-stack component, I had the following in /gltests/test-suite.log: "FAIL: test-c-stack.sh ===================== ./test-c-stack.sh: line 7: 3238828 Segmentation fault (core dumped) ${CHECKER} ./test-c-stack${EXEEXT} 2> t-c-stack.tmp FAIL test-c-stack.sh (exit status: 1) I didn’t get much particularly useful out of gdb yet: Reading symbols from ./test-c-stack... (gdb) r Starting program: /tmp/gnulib/foo/gltests/test-c-stack Program received signal SIGSEGV, Segmentation fault. 0x0000010000000c64 in recurse_1 (n=<optimized out>, p=0xffffffffffffffff) at test-c-stack.c:35 35 { (gdb) bt #0 0x0000010000000c64 in recurse_1 (n=<optimized out>, p=0xffffffffffffffff) at test-c-stack.c:35 #1 0x0000000000000007 in ?? () Backtrace stopped: previous frame identical to this frame (corrupt stack?)" The grep investigation was similar: "(gdb) r Starting program: /var/tmp/portage/sys-apps/grep-3.6/work/grep-3.6/src/grep -E -f in [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib64/libthread_db.so.1". Program received signal SIGSEGV, Segmentation fault. 0x0000010000026908 in peek_token (token=0x10000aa9f30, input=0x10000aa9f30, syntax=1099522809648) at regcomp.c:1784 1784 { (gdb) bt #0 0x0000010000026908 in peek_token (token=0x10000aa9f30, input=0x10000aa9f30, syntax=1099522809648) at regcomp.c:1784 #1 0x0000010000aa9f38 in ?? () Backtrace stopped: previous frame inner to this frame (corrupt stack?) (gdb)" Please let me know what further information I can provide and how to better debug this, thanks a bunch! [0] https://lists.gnu.org/archive/html/bug-grep/2021-02/msg00000.html.