From: "Maciej W. Rozycki" <macro@codesourcery.com>
To: <gdb-patches@sourceware.org>
Subject: [PATCH] Also mark ELF solib trampoline minimal symbols special
Date: Wed, 17 Sep 2014 23:03:00 -0000 [thread overview]
Message-ID: <alpine.DEB.1.10.1409162318090.27075@tp.orcam.me.uk> (raw)
Hi,
In installing minimal symbols for ELF shared library trampolines we
"forget" to make individual symbols special where required. This leads to
problems on the MIPS target using microMIPS SVR4 lazy stubs. Lacking the
special annotation these stubs are treated as standard MIPS code and this
makes GDB insert the wrong software breakpoint instruction, breaking e.g.
single-stepping through these stubs. This is not a very frequent scenario
as microMIPS SVR4 lazy stubs are typically only used in shared libraries
with the main executable using PLT, handled elsewhere. Still it triggers
e.g. when a software watchpoint has been installed. The symptom is SIGILL
or the program going astray, depending on the endianness. Disassembly of
these stubs is also wrong.
Regression-tested with the mips-linux-gnu target and the following
multilibs:
-EB
-EB -msoft-float
-EB -mips16
-EB -mips16 -msoft-float
-EB -mmicromips
-EB -mmicromips -msoft-float
-EB -mabi=n32
-EB -mabi=n32 -msoft-float
-EB -mabi=64
-EB -mabi=64 -msoft-float
and the -EL variants of same with no regressions and the following
big-endian failures removed:
(gdb) PASS: gdb.base/watchpoint-solib.exp: rerun to main
continue
Continuing.
Program received signal SIGILL, Illegal instruction.
0x2aad36ab in _dl_sym () at dl-sym.c:282
282 {
(gdb) FAIL: gdb.base/watchpoint-solib.exp: continue to foo again
continue
Continuing.
Program terminated with signal SIGILL, Illegal instruction.
The program no longer exists.
(gdb) FAIL: gdb.base/watchpoint-solib.exp: continue to watchpoint hit again
and similarly for the little endianness:
(gdb) PASS: gdb.base/watchpoint-solib.exp: rerun to main
continue
Continuing.
FAIL: gdb.base/watchpoint-solib.exp: continue to foo again (timeout)
continue
FAIL: gdb.base/watchpoint-solib.exp: continue to watchpoint hit again (timeout)
-- across the -mmicromips multilibs.
OK to apply?
2014-09-17 Maciej W. Rozycki <macro@codesourcery.com>
gdb/
* elfread.c (elf_symtab_read): Also mark solib trampoline minimal
symbols special.
Maciej
gdb-msymbol-solib-trampoline-special.diff
Index: gdb-fsf-trunk-quilt/gdb/elfread.c
===================================================================
--- gdb-fsf-trunk-quilt.orig/gdb/elfread.c 2014-08-23 01:11:20.000000000 +0100
+++ gdb-fsf-trunk-quilt/gdb/elfread.c 2014-09-16 22:56:52.318922758 +0100
@@ -328,7 +328,10 @@ elf_symtab_read (struct objfile *objfile
(sym->name, strlen (sym->name), copy_names,
symaddr, mst_solib_trampoline, sect, objfile);
if (msym != NULL)
- msym->filename = filesymname;
+ {
+ msym->filename = filesymname;
+ gdbarch_elf_make_msymbol_special (gdbarch, sym, msym);
+ }
continue;
}
next reply other threads:[~2014-09-17 23:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-17 23:03 Maciej W. Rozycki [this message]
2014-09-26 22:12 ` [PING][PATCH] " Maciej W. Rozycki
2014-10-03 11:39 ` [PING^2][PATCH] " Maciej W. Rozycki
2014-10-03 11:51 ` [PATCH] " Pedro Alves
2014-10-03 16:45 ` Maciej W. Rozycki
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=alpine.DEB.1.10.1409162318090.27075@tp.orcam.me.uk \
--to=macro@codesourcery.com \
--cc=gdb-patches@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).