From: "Christian Häggström (Code Review)" <gerrit@gnutoolchain-gerrit.osci.io>
To: Florian Weimer <fweimer@redhat.com>,
Florian Weimer <fw@deneb.enyo.de>,
libc-alpha@sourceware.org
Subject: [review v2] Remove all loaded objects if dlopen fails, ignoring NODELETE [BZ #20839]
Date: Wed, 13 Nov 2019 14:28:00 -0000 [thread overview]
Message-ID: <20191113142805.9A5CD20AF6@gnutoolchain-gerrit.osci.io> (raw)
In-Reply-To: <gerrit.1572549639000.Ib2a3d86af6f92d75baca65431d74783ee0dbc292@gnutoolchain-gerrit.osci.io>
Christian Häggström has posted comments on this change.
Change URL: https://gnutoolchain-gerrit.osci.io/r/c/glibc/+/471
......................................................................
Patch Set 2: Code-Review+1
(3 comments)
| --- elf/dl-lookup.c
| +++ elf/dl-lookup.c
| @@ -315,6 +315,17 @@ #define INITIAL_NUNIQUE_SYM_TABLE 31
| - setting the appropriate flag. */
| - ((struct link_map *) map)->l_flags_1 |= DF_1_NODELETE;
| + {
| + /* Make sure we don't unload this object by
| + setting the appropriate flag. */
| + if (__glibc_unlikely (GLRO (dl_debug_mask) & DL_DEBUG_BINDINGS)
| + && map->l_nodelete == link_map_nodelete_inactive)
| + _dl_debug_printf ("\
| +marking %s [%lu] as NODELETE due to unique symbol\n",
| + map->l_name, map->l_ns);
PS1, Line 322:
Yes, I mean to wrap both the if statement and _dl_debug_printf in a
macro. But I agree it is a separate cleanup. Marking as resolved.
| + if (flags & DL_LOOKUP_FOR_RELOCATE)
| + map->l_nodelete = link_map_nodelete_pending;
| + else
| + map->l_nodelete = link_map_nodelete_active;
| + }
| }
| ++tab->n_elements;
|
| #ifdef SHARED
| --- include/link.h
| +++ include/link.h
| @@ -82,7 +85,19 @@ enum link_map_nodelete
| + /* This link map can be deallocated. */
| + link_map_nodelete_inactive,
| +
| + /* This link map cannot be deallocated. */
| + link_map_nodelete_active,
| +
| + /* This link map cannot be deallocated after dlopen has succeded.
| + dlopen turns this into link_map_nodelete_active. dlclose treats
| + this intermediate state as link_map_nodelete_active. */
| + link_map_nodelete_pending,
PS1, Line 94:
Ok, leave it in lowercase and we can make a separate patch changing
all existing constants to caps. Resolving thread.
| +};
| +
|
| /* Structure describing a loaded shared object. The `l_next' and `l_prev'
| members form a chain of all the shared objects loaded at startup.
|
| These data structures exist in space used by the run-time dynamic linker;
| modifying them may have disastrous results.
|
...
| @@ -199,15 +214,19 @@ struct link_map
| during LD_TRACE_PRELINKING=1
| contains any DT_SYMBOLIC
| libraries. */
| unsigned int l_free_initfini:1; /* Nonzero if l_initfini can be
| freed, ie. not allocated with
| the dummy malloc in ld.so. */
|
| + /* Actually of type enum link_map_nodelete. Separate byte due to
| + concurrent access. Only valid for l_type == lt_loaded. */
| + unsigned char l_nodelete;
PS1, Line 223:
Uh, reads to concurrent variables with unspecified memory ordering is
a ticking bomb as the compilers gets smarter. But that's a separate
issue. Glad you have updated the comment.
Thanks for commenting the initializer value. Marking resolved.
| +
| #include <link_map.h>
|
| /* Collected information about own RPATH directories. */
| struct r_search_path_struct l_rpath_dirs;
|
| /* Collected results of relocation while profiling. */
| struct reloc_result
| {
--
Gerrit-Project: glibc
Gerrit-Branch: master
Gerrit-Change-Id: Ib2a3d86af6f92d75baca65431d74783ee0dbc292
Gerrit-Change-Number: 471
Gerrit-PatchSet: 2
Gerrit-Owner: Florian Weimer <fweimer@redhat.com>
Gerrit-Reviewer: Christian Häggström <gnugerrit@kalvdans.no-ip.org>
Gerrit-Reviewer: Florian Weimer <fweimer@redhat.com>
Gerrit-Comment-Date: Wed, 13 Nov 2019 14:28:05 +0000
Gerrit-HasComments: Yes
Gerrit-Has-Labels: Yes
Comment-In-Reply-To: Florian Weimer <fweimer@redhat.com>
Comment-In-Reply-To: Christian Häggström <gnugerrit@kalvdans.no-ip.org>
Gerrit-MessageType: comment
next prev parent reply other threads:[~2019-11-13 14:28 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-31 19:21 [review] " Florian Weimer (Code Review)
2019-10-31 20:18 ` Christian Häggström (Code Review)
2019-11-13 12:56 ` [review v2] " Florian Weimer (Code Review)
2019-11-13 14:28 ` Christian Häggström (Code Review) [this message]
2019-11-15 16:02 ` [review v3] " Florian Weimer (Code Review)
2019-12-02 16:07 ` Florian Weimer
2019-12-02 16:53 ` Carlos O'Donell
2019-11-21 12:57 ` Carlos O'Donell (Code Review)
2019-11-27 20:31 ` [pushed] " Sourceware to Gerrit sync (Code Review)
2019-12-02 10:07 ` Szabolcs Nagy
2019-12-02 12:17 ` Florian Weimer
2019-12-02 13:52 ` Szabolcs Nagy
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=20191113142805.9A5CD20AF6@gnutoolchain-gerrit.osci.io \
--to=gerrit@gnutoolchain-gerrit.osci.io \
--cc=fw@deneb.enyo.de \
--cc=fweimer@redhat.com \
--cc=gnutoolchain-gerrit@osci.io \
--cc=libc-alpha@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).