Date: Wed, 31 Oct 2018 16:08:06 +0100 From: Michael Tuexen <tuexen@freebsd.org> To: Mark Millard <marklmi@yahoo.com> Cc: FreeBSD PowerPC ML <freebsd-ppc@freebsd.org>, Alexander Richardson <arichardson@freebsd.org> Subject: Re: svn commit: r339876 - head/libexec/rtld-elf Message-ID: <24896738-5D46-46FB-A41A-E6719F169109@freebsd.org> In-Reply-To: <77371AC1-C422-47A6-9EA5-9A92F958D86B@yahoo.com> References: <B4656C50-1A08-4E0E-B0F4-2DA527840679@macmic.franken.de> <DD8CF13B-DD0A-4DBA-BA5E-242BD791A878@freebsd.org> <77371AC1-C422-47A6-9EA5-9A92F958D86B@yahoo.com>
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> On 31. Oct 2018, at 15:33, Mark Millard <marklmi@yahoo.com> wrote: > > On 2018-Oct-30, at 3:59 AM, Michael Tuexen <tuexen at freebsd.org> wrote: > >> FYI >> >>> Begin forwarded message: >>> >>> From: Michael Tuexen <Michael.Tuexen at macmic.franken.de> >>> Subject: Re: svn commit: r339876 - head/libexec/rtld-elf >>> Date: 30. October 2018 at 11:17:39 CET >>> To: Alex Richardson <arichardson@FreeBSD.org> >>> Cc: src-committers <src-committers@freebsd.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org >>> >>>> On 29. Oct 2018, at 22:08, Alex Richardson <arichardson@FreeBSD.org> wrote: >>>> >>>> Author: arichardson >>>> Date: Mon Oct 29 21:08:02 2018 >>>> New Revision: 339876 >>>> URL: https://svnweb.freebsd.org/changeset/base/339876 >>>> >>>> Log: >>>> rtld: set obj->textsize correctly >>>> >>>> With lld-generated binaries the first PT_LOAD will usually be a read-only >>>> segment unless you pass --no-rosegment. For those binaries the textsize is >>>> determined by the next PT_LOAD. To allow both LLD and bfd 2.17 binaries to >>>> be parsed correctly use the end of the last PT_LOAD that is marked as >>>> executable instead. >>>> >>>> I noticed that the value was wrong while adding some debug prints for some rtld >>>> changes for CHERI binaries. `obj->textsize` only seems to be used by PPC so the >>>> effect is untested. However, the value before was definitely wrong and the new >>>> result matches the phdrs. >>> I build kernel and world with a revision later than this on a PPC. > > Which have you tried: 32 bit? 64 bit? Both? If both, do both fail? Both. Only the 32-bit version shows the problem. Reverting this commit and rebuilding /libexec/ld-elf.so.1 resolves the problem. So I can confirm that this commit results in problems for 32-bit powerppc. > > What version did the buildworld buildkernel ? What version was > built by the buildworld buildkernel (that was later installed > and had failures)? I was building r339914. > > Do you know what version did the prior buildworld buildkernel (that > produced the version that did this buildworld buildkernel)? If yes, > what was it? No. Just reverting this commit resolves the issue. > >>> Buildword >>> ends up with a world where almost all binaries are segfaulting.... Especially gdb >>> (but svn, ls or so all segfault). > > Which fail: > > /usr/local/bin/gdb ? /usr/libexec/gdb ? Both? > /usr/local/bin/svn ? /usr/bin/svnlite ? Both? > /bin/ls ? /rescue/ls ? Both? > > That last may be the more important comparison. Not the ones from /rescue. I used these tools to recover the system. Failing binaries where /usr/local/bin/gdb, /usr/local/bin/svn. You can reproduce the issue. Just update the sources and to make and make install in head/libexec/rtld-elf Best regards Michael > >>> >>> Best regards >>> Michael >>>> >>>> Reviewed By: kib >>>> Approved By: brooks (mentor) >>>> Differential Revision: https://reviews.freebsd.org/D17117 >>>> >>>> Modified: >>>> head/libexec/rtld-elf/map_object.c >>>> head/libexec/rtld-elf/rtld.c >>>> >>>> Modified: head/libexec/rtld-elf/map_object.c >>>> ============================================================================== >>>> --- head/libexec/rtld-elf/map_object.c Mon Oct 29 21:03:43 2018 (r339875) >>>> +++ head/libexec/rtld-elf/map_object.c Mon Oct 29 21:08:02 2018 (r339876) >>>> @@ -93,6 +93,7 @@ map_object(int fd, const char *path, const struct stat >>>> Elf_Addr note_end; >>>> char *note_map; >>>> size_t note_map_len; >>>> + Elf_Addr text_end; >>>> >>>> hdr = get_elf_header(fd, path, sb); >>>> if (hdr == NULL) >>>> @@ -116,6 +117,7 @@ map_object(int fd, const char *path, const struct stat >>>> note_map = NULL; >>>> segs = alloca(sizeof(segs[0]) * hdr->e_phnum); >>>> stack_flags = RTLD_DEFAULT_STACK_PF_EXEC | PF_R | PF_W; >>>> + text_end = 0; >>>> while (phdr < phlimit) { >>>> switch (phdr->p_type) { >>>> >>>> @@ -130,6 +132,10 @@ map_object(int fd, const char *path, const struct stat >>>> path, nsegs); >>>> goto error; >>>> } >>>> + if ((segs[nsegs]->p_flags & PF_X) == PF_X) { >>>> + text_end = MAX(text_end, >>>> + round_page(segs[nsegs]->p_vaddr + segs[nsegs]->p_memsz)); >>>> + } >>>> break; >>>> >>>> case PT_PHDR: >>>> @@ -280,8 +286,7 @@ map_object(int fd, const char *path, const struct stat >>>> } >>>> obj->mapbase = mapbase; >>>> obj->mapsize = mapsize; >>>> - obj->textsize = round_page(segs[0]->p_vaddr + segs[0]->p_memsz) - >>>> - base_vaddr; >>>> + obj->textsize = text_end - base_vaddr; >>>> obj->vaddrbase = base_vaddr; >>>> obj->relocbase = mapbase - base_vaddr; >>>> obj->dynamic = (const Elf_Dyn *) (obj->relocbase + phdyn->p_vaddr); >>>> >>>> Modified: head/libexec/rtld-elf/rtld.c >>>> ============================================================================== >>>> --- head/libexec/rtld-elf/rtld.c Mon Oct 29 21:03:43 2018 (r339875) >>>> +++ head/libexec/rtld-elf/rtld.c Mon Oct 29 21:08:02 2018 (r339876) >>>> @@ -1390,13 +1390,15 @@ digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t e >>>> if (nsegs == 0) { /* First load segment */ >>>> obj->vaddrbase = trunc_page(ph->p_vaddr); >>>> obj->mapbase = obj->vaddrbase + obj->relocbase; >>>> - obj->textsize = round_page(ph->p_vaddr + ph->p_memsz) - >>>> - obj->vaddrbase; >>>> } else { /* Last load segment */ >>>> obj->mapsize = round_page(ph->p_vaddr + ph->p_memsz) - >>>> obj->vaddrbase; >>>> } >>>> nsegs++; >>>> + if ((ph->p_flags & PF_X) == PF_X) { >>>> + obj->textsize = MAX(obj->textsize, >>>> + round_page(ph->p_vaddr + ph->p_memsz) - obj->vaddrbase); >>>> + } >>>> break; >>>> >>>> case PT_DYNAMIC: >>>> >>> >>> >> > > > === > Mark Millard > marklmi at yahoo.com > ( dsl-only.net went > away in early 2018-Mar) >home | help
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