> (gdb) p *(*preloads)->l_next
> $11 = {l_addr = 1076473856, l_name = 0x40000e78 "/lib/libdl.so.2",
> l_ld = 0x4029e5fc, l_next = 0x40001118, l_prev = 0x40000bf0,
> l_real = 0x40000e88, l_ns = 0, l_libname = 0x400010dc, l_info = {0x0,
> 0x4029e5fc, 0x0 <repeats 74 times>}, l_phdr = 0x4029b034,
> l_entry = 1076477148, l_phnum = 7, l_ldnum = 31, l_searchlist = {
> r_list = 0x0, r_nlist = 0}, l_symbolic_searchlist = {r_list = 0x400010d8,
> r_nlist = 0}, l_loader = 0x403d8880, l_versions = 0x0, l_nversions = 0,
> l_nbuckets = 0, l_gnu_bitmask_idxbits = 0, l_gnu_shift = 0,
> l_gnu_bitmask = 0x0, {l_gnu_buckets = 0x0, l_chain = 0x0}, {
> l_gnu_chain_zero = 0x0, l_buckets = 0x0}, l_direct_opencount = 0,
> l_type = lt_library, l_relocated = 0, l_init_called = 0, l_global = 0,
> l_reserved = 1, l_phdr_allocated = 0, l_soname_added = 0, l_faked = 0,
> l_need_tls_init = 0, l_used = 0, l_auditing = 0, l_audit_any_plt = 0,
> l_removed = 0, l_contiguous = 1, l_rpath_dirs = {dirs = 0x0, malloced = 0},
> l_reloc_result = 0x0, l_versyms = 0x0, l_origin = 0x400010f8 "/lib",
> l_map_start = 1076473856, l_map_end = 1076488476, l_text_end = 1076490240,
> l_scope_mem = {0x403d89dc, 0x0, 0x0, 0x0}, l_scope_max = 4,
> l_scope = 0x40001040, l_local_scope = {0x40000fe4, 0x0}, l_dev = 536937216,
> l_ino = 641559, l_runpath_dirs = {dirs = 0x0, malloced = 0},
> l_initfini = 0x0, l_reldepsmax = 0, l_reldeps = 0x0, l_feature_1 = 0,
> l_flags_1 = 0, l_flags = 0, l_idx = 0, l_mach = {fptr_table_len = 0,
> fptr_table = 0x0}, l_lookup_cache = {sym = 0x0, type_class = 0,
> value = 0x0, ret = 0x0}, l_tls_initimage = 0x0, l_tls_initimage_size = 0,
> l_tls_blocksize = 0, l_tls_align = 0, l_tls_firstbyte_offset = 0,
> l_tls_offset = 0, l_tls_modid = 0, l_relro_addr = 0, l_relro_size = 0,
> l_serial = 3, l_audit = 0x400010d8}
>
> (gdb) p &(*preloads)->l_next->l_info
> $14 = (Elf32_Dyn *(*)[76]) 0x40000ea8
> (gdb) p (*preloads)->l_next->l_info
> $15 = {0x0, 0x4029e5fc, 0x0 <repeats 74 times>}
> (gdb) p/x 0x40000ea8 + 5 * 4
> $17 = 0x40000ebc
>
> So, the segmentation fault was caused by a 0x0 in the l_info field of
> the link map for "/lib/libdl.so.2".
After staring at the dynamic loader code for a while, I think the following
mmap call in dl-load.c doesn't correctly map the info data for /lib/libdl.so.2.
/* Remember which part of the address space this object uses. */
l->l_map_start = (ElfW(Addr)) __mmap ((void *) mappref, maplength,
c->prot,
MAP_COPY|MAP_FILE,
fd, c->mapoff);
The info data is near the end of the mapped segment. The l_info field
is initialized by elf_get_dynamic_info from the dynamic data mapped
at l->ld.
I seem to recall that the kernel mmap implementation on hppa is somewhat
unique.
In the above call, mappref is NULL. The kernel selects the map location.
Dave
--
J. David Anglin dave.anglin@xxxxxxxxxxxxxx
National Research Council of Canada (613) 990-0752 (FAX: 952-6602)
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