Module Name: src
Committed By: rin
Date: Sun Jun 26 08:28:07 UTC 2022
Modified Files:
src/external/gpl3/gdb/dist/gdb: solib-svr4.c
Log Message:
PR toolchain/56268
For NetBSD/m68k, program header is erroneously readable from core dump,
although a page containing it is missing. This spoils relocation for
the main executable, and debugging with core dumps becomes impossible,
as described in the PR.
In order to avoid this failure, add consistency check for program header;
for NetBSD, 1st entry of program header refers program header itself. If
this is not the case, we should be reading random garbage from core dump.
Yes, this is a kind of the hackest hack. But, unable to debug with core
dump is critical. Therefore, I commit this workaround temporarily until
the real cause is found and fixed.
Note that this is not a recent regression for GDB nor kernel, as
mentioned in the PR. These from netbsd-8 and -9 fail in the same way
without this hack.
To generate a diff of this commit:
cvs rdiff -u -r1.1.1.9 -r1.2 src/external/gpl3/gdb/dist/gdb/solib-svr4.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/external/gpl3/gdb/dist/gdb/solib-svr4.c
diff -u src/external/gpl3/gdb/dist/gdb/solib-svr4.c:1.1.1.9 src/external/gpl3/gdb/dist/gdb/solib-svr4.c:1.2
--- src/external/gpl3/gdb/dist/gdb/solib-svr4.c:1.1.1.9 Tue Sep 15 01:43:33 2020
+++ src/external/gpl3/gdb/dist/gdb/solib-svr4.c Sun Jun 26 08:28:07 2022
@@ -541,6 +541,40 @@ read_program_header (int type, int *p_ar
if (target_read_memory (sect_addr, buf.data (), sect_size))
return {};
+#if defined(__NetBSD__) && defined(__m68k__)
+ /*
+ * XXX PR toolchain/56268
+ *
+ * For NetBSD/m68k, program header is erroneously readable from core dump,
+ * although a page containing it is missing. This spoils relocation for
+ * the main executable, and debugging with core dumps becomes impossible,
+ * as described in toolchain/56268.
+ *
+ * In order to avoid this failure, we carry out consistency check for
+ * program header; for NetBSD, 1st entry of program header refers program
+ * header itself. If this is not the case, we should be reading random
+ * garbage from core dump.
+ */
+ if (type == -1 && arch_size == 32)
+ {
+ Elf32_External_Phdr phdr;
+ int p_type, p_filesz, p_memsz;
+
+ if (target_read_memory (at_phdr, (gdb_byte *)&phdr, sizeof (phdr)))
+ return {};
+
+ p_type = extract_unsigned_integer ((gdb_byte *) phdr.p_type, 4,
+ byte_order);
+ p_filesz = extract_unsigned_integer ((gdb_byte *)phdr.p_filesz, 4,
+ byte_order);
+ p_memsz = extract_unsigned_integer ((gdb_byte *)phdr.p_memsz, 4,
+ byte_order);
+
+ if (p_type != PT_PHDR || p_filesz != sect_size || p_memsz != sect_size)
+ return {};
+ }
+#endif
+
if (p_arch_size)
*p_arch_size = arch_size;
if (base_addr)
