From: Tom de Vries Date: Thu, 27 May 2021 13:22:38 +0000 (+0200) Subject: [gdb/symtab] Fix segfault in process_psymtab_comp_unit X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=248f7165005096fc618c5fd9bf3588719fc589ef;p=binutils-gdb.git [gdb/symtab] Fix segfault in process_psymtab_comp_unit When running test-case gdb.dwarf2/dw2-dummy-cu.exp without -readnow, we run into: ... (gdb) file outputs/gdb.dwarf2/dw2-dummy-cu/dw2-dummy-cu^M Reading symbols from outputs/gdb.dwarf2/dw2-dummy-cu/dw2-dummy-cu...^M ERROR: Couldn't load dw2-dummy-cu into GDB (eof). ... The problem is that we're running into a segfault: ... Thread 1 "gdb" received signal SIGSEGV, Segmentation fault. process_psymtab_comp_unit (this_cu=0x2141090, per_objfile=0x1aa4140, want_partial_unit=false, pretend_language=language_minimal) at /home/vries/gdb_versions/devel/src/gdb/dwarf2/read.c:7023 7023 switch (reader.comp_unit_die->tag) ... due to reader.comp_unit_die == nullptr: ... (gdb) p reader.comp_unit_die $1 = (die_info *) 0x0 ... Indeed, there's no CU DIE in the test-case: ... $ readelf -wi outputs/gdb.dwarf2/dw2-dummy-cu/dw2-dummy-cu Contents of the .debug_info section: Compilation Unit @ offset 0x0: Length: 0x7 (32-bit) Version: 2 Abbrev Offset: 0x0 Pointer Size: 4 $ ... Fix this by handling reader.comp_unit_die == nullptr in process_psymtab_comp_unit. Update the test-case to trigger this PR, as per PR27920 - "[gdb/testsuite] hardcoding -readnow skips testing of partial symbols". Tested on x86_64-linux. gdb/ChangeLog: 2021-05-27 Tom de Vries PR symtab/27919 * dwarf2/read.c (process_psymtab_comp_unit): gdb/testsuite/ChangeLog: 2021-05-27 Tom de Vries PR symtab/27919 PR testsuite/27920 * gdb.dwarf2/dw2-dummy-cu.exp: Use maint expand-symtabs instead of -readnow. --- diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 3c0c2db7147..6170d2dc56c 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2021-05-27 Tom de Vries + + PR symtab/27919 + * dwarf2/read.c (process_psymtab_comp_unit): + 2021-05-27 Tom de Vries * dwarf2/read.c (find_partial_die): Fix "Cannot not" typo in dwarf diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index 0da87bbecd6..4cc5b4f32d7 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -7020,6 +7020,9 @@ process_psymtab_comp_unit (dwarf2_per_cu_data *this_cu, cutu_reader reader (this_cu, per_objfile, nullptr, nullptr, false); + if (reader.comp_unit_die == nullptr) + return; + switch (reader.comp_unit_die->tag) { case DW_TAG_compile_unit: diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 968e623db40..22a99c0cc5e 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,10 @@ +2021-05-27 Tom de Vries + + PR symtab/27919 + PR testsuite/27920 + * gdb.dwarf2/dw2-dummy-cu.exp: Use maint expand-symtabs instead of + -readnow. + 2021-05-27 Tom de Vries PR testsuite/27921 diff --git a/gdb/testsuite/gdb.dwarf2/dw2-dummy-cu.exp b/gdb/testsuite/gdb.dwarf2/dw2-dummy-cu.exp index 673972447a1..7871851e577 100644 --- a/gdb/testsuite/gdb.dwarf2/dw2-dummy-cu.exp +++ b/gdb/testsuite/gdb.dwarf2/dw2-dummy-cu.exp @@ -27,13 +27,9 @@ if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" object {}] != " return -1 } -set saved_gdbflags $GDBFLAGS -set GDBFLAGS "$GDBFLAGS -readnow" - clean_restart $executable +gdb_test_no_output "maint expand-symtab" # Something simple to verify gdb didn't crash, and has read in whatever symbol # info is there. gdb_test "info fun main" "main_end" - -set GDBFLAGS $saved_gdbflags