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| author | Jan Kratochvil <jan.kratochvil@redhat.com> | 2015-02-26 14:08:01 +0100 |
|---|---|---|
| committer | Jan Kratochvil <jan.kratochvil@redhat.com> | 2015-02-26 14:08:01 +0100 |
| commit | 80c570537e380c1b8e48754c0ddbce2abcde2d00 (patch) | |
| tree | 8c66446178e584818daad632f740e7022a55af8e /gdb/elfread.c | |
| parent | e3ee40059d4a4e04d10e2b5c46bacd2a810355ca (diff) | |
SEGV in ppc64_elf_get_synthetic_symtab reading a separate debug file
The attached patch fixes the SEGV and lets GDB successfully
load all kernel modules installed by default on RHEL 7.
Valgrind on F-21 x86_64 host has shown me more clear what is the problem:
Reading symbols from /home/jkratoch/t/cordic.ko...Reading symbols from
/home/jkratoch/t/cordic.ko.debug...=================================================================
==22763==ERROR: AddressSanitizer: heap-use-after-free on address 0x6120000461c8 at pc 0x150cdbd bp 0x7fffffffc7e0 sp 0x7fffffffc7d0
READ of size 8 at 0x6120000461c8 thread T0
#0 0x150cdbc in ppc64_elf_get_synthetic_symtab /home/jkratoch/redhat/gdb-test-asan/bfd/elf64-ppc.c:3282
#1 0x8c5274 in elf_read_minimal_symbols /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1205
#2 0x8c55e7 in elf_symfile_read /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1268
[...]
0x6120000461c8 is located 264 bytes inside of 288-byte region [0x6120000460c0,0x6120000461e0)
freed by thread T0 here:
#0 0x7ffff715454f in __interceptor_free (/lib64/libasan.so.1+0x5754f)
#1 0xde9cde in xfree common/common-utils.c:98
#2 0x9a04f7 in do_my_cleanups common/cleanups.c:155
#3 0x9a05d3 in do_cleanups common/cleanups.c:177
#4 0x8c538a in elf_read_minimal_symbols /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1229
#5 0x8c55e7 in elf_symfile_read /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1268
[...]
previously allocated by thread T0 here:
#0 0x7ffff71547c7 in malloc (/lib64/libasan.so.1+0x577c7)
#1 0xde9b95 in xmalloc common/common-utils.c:41
#2 0x8c4da2 in elf_read_minimal_symbols /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1147
#3 0x8c55e7 in elf_symfile_read /home/jkratoch/redhat/gdb-test-asan/gdb/elfread.c:1268
[...]
SUMMARY: AddressSanitizer: heap-use-after-free /home/jkratoch/redhat/gdb-test-asan/bfd/elf64-ppc.c:3282 ppc64_elf_get_synthetic_symtab
[...]
==22763==ABORTING
A similar case a few lines later I have fixed in 2010 by:
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=3f1eff0a2c7f0e7078f011f55b8e7f710aae0cc2
My testcase does not always reproduce it but at least a bit:
* GDB without ppc64 target (even as a secondary one) is reported as "untested"
* ASAN-built GDB with ppc64 target always crashes (and PASSes with this fix)
* unpatched non-ASAN-built GDB with ppc64 target crashes from commandline
* unpatched non-ASAN-built GDB with ppc64 target PASSes from runtest (?)
gdb/ChangeLog
2015-02-26 Jan Kratochvil <jan.kratochvil@redhat.com>
* elfread.c (elf_read_minimal_symbols): Use bfd_alloc for
bfd_canonicalize_symtab.
gdb/testsuite/ChangeLog
2015-02-26 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.arch/cordic.ko.bz2: New file.
* gdb.arch/cordic.ko.debug.bz2: New file.
* gdb.arch/ppc64-symtab-cordic.exp: New file.
Diffstat (limited to 'gdb/elfread.c')
| -rw-r--r-- | gdb/elfread.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/gdb/elfread.c b/gdb/elfread.c index 65c63f0538..4a6576f802 100644 --- a/gdb/elfread.c +++ b/gdb/elfread.c @@ -1144,8 +1144,10 @@ elf_read_minimal_symbols (struct objfile *objfile, int symfile_flags, if (storage_needed > 0) { - symbol_table = (asymbol **) xmalloc (storage_needed); - make_cleanup (xfree, symbol_table); + /* Memory gets permanently referenced from ABFD after + bfd_canonicalize_symtab so it must not get freed before ABFD gets. */ + + symbol_table = bfd_alloc (abfd, storage_needed); symcount = bfd_canonicalize_symtab (objfile->obfd, symbol_table); if (symcount < 0) |