[Bug pch/45979] New: precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[Bug pch/45979] New: precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

           Summary: precompiled headers breakage on 2.6.36-rc Linux/ARM
                    kernels
           Product: gcc
           Version: 4.4.5
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: pch
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mikpe@it.uu.se


Recently I've started seeing massive pch test suite failures with gcc,
both trunk and 4.4, on armv5tel-linux-gnueabi:

FAIL: gcc.dg/pch/common-1.c  -O2  -I. (test for excess errors)
FAIL: gcc.dg/pch/common-1.c  -O2  assembly comparison
FAIL: gcc.dg/pch/common-1.c  -O3 -fomit-frame-pointer  -I. (test for excess
errors)
FAIL: gcc.dg/pch/common-1.c  -O3 -fomit-frame-pointer  assembly comparison
FAIL: gcc.dg/pch/counter-1.c -O0 -g -I. (test for excess errors)
FAIL: gcc.dg/pch/counter-1.c -O0 -g assembly comparison
FAIL: gcc.dg/pch/counter-1.c  -O3 -g  -I. (test for excess errors)
FAIL: gcc.dg/pch/counter-1.c  -O3 -g  assembly comparison
FAIL: gcc.dg/pch/cpp-1.c -O0 -g -I. (test for excess errors)
FAIL: gcc.dg/pch/cpp-1.c -O0 -g assembly comparison
...(many many more)

These failures started after I did a major update of the Linux distro
I run on my ARM boxes.  I reverted a few likely suspects (glibc and
the system gcc) to their earlier known-good versions, without effect,
but in the end the failures were traced to the Linux kernel:

- running linux-2.6.36-rc6 causes these PCH failures
- reverting to linux-2.6.35 (similar .config) makes PCH tests pass again
- pre-2.6.35 kernels are also known good

The PCH test suite failures come from ICEs in cc1.  I saved a core dump
of which gdb says the following:

Core was generated by `/home/mikpe/objdir/gcc/cc1 -quiet -I. -I. -iprefix
/home/mikpe/temp/lib/gcc/arm'.
Program terminated with signal 11, Segmentation fault.
#0  linemap_lookup (set=0x40215000, line=73) at
/home/mikpe/gcc-4.4-20100921/libcpp/line-map.c:284
284       if (line >= cached->start_location)
Missing separate debuginfos, use: debuginfo-install glibc-2.10.2-1.bl8.armv5tel
gmp-4.3.2-1.bl11.armv5tel mpfr-2.4.2-2.bl11.armv5tel
(gdb) bt
#0  linemap_lookup (set=0x40215000, line=73) at
/home/mikpe/gcc-4.4-20100921/libcpp/line-map.c:284
#1  0x000cbed0 in diagnostic_report_current_module (context=0x790888)
    at /home/mikpe/gcc-4.4-20100921/gcc/diagnostic.c:236
#2  0x000cbffc in diagnostic_report_current_function (context=0xa4680042,
diagnostic=0x49)
    at /home/mikpe/gcc-4.4-20100921/gcc/diagnostic.c:218
#3  0x000cc240 in default_diagnostic_starter (context=0xa4680042,
diagnostic=0x49)
    at /home/mikpe/gcc-4.4-20100921/gcc/diagnostic.c:263
#4  0x000cb6c4 in diagnostic_report_diagnostic (context=0x790888,
diagnostic=0xbe88b8e0)
    at /home/mikpe/gcc-4.4-20100921/gcc/diagnostic.c:403
#5  0x000cb940 in internal_error (gmsgid=0x6ecd70 "%s")
    at /home/mikpe/gcc-4.4-20100921/gcc/diagnostic.c:658
#6  0x00261cec in crash_signal (signo=-1098336032) at
/home/mikpe/gcc-4.4-20100921/gcc/toplev.c:601
#7  <signal handler called>
#8  linemap_lookup (set=0x40215000, line=73) at
/home/mikpe/gcc-4.4-20100921/libcpp/line-map.c:284
#9  0x000cbed0 in diagnostic_report_current_module (context=0x790888)
    at /home/mikpe/gcc-4.4-20100921/gcc/diagnostic.c:236
#10 0x000cbffc in diagnostic_report_current_function (context=0xa4680042,
diagnostic=0x49)
    at /home/mikpe/gcc-4.4-20100921/gcc/diagnostic.c:218
#11 0x000cc240 in default_diagnostic_starter (context=0xa4680042,
diagnostic=0x49)
    at /home/mikpe/gcc-4.4-20100921/gcc/diagnostic.c:263
#12 0x000cb6c4 in diagnostic_report_diagnostic (context=0x790888,
diagnostic=0xbe88bcf8)
    at /home/mikpe/gcc-4.4-20100921/gcc/diagnostic.c:403
#13 0x000cbab0 in fatal_error (gmsgid=0x5ca9f0 "had to relocate PCH")
    at /home/mikpe/gcc-4.4-20100921/gcc/diagnostic.c:640
#14 0x0015da80 in gt_pch_restore (f=0xbe88bcf8) at
/home/mikpe/gcc-4.4-20100921/gcc/ggc-common.c:576
#15 0x00054608 in c_common_read_pch (pfile=0x134f170, name=0x1347a68
"./valid-6.h.gch", 
    fd=<value optimized out>, orig_name=<value optimized out>)
    at /home/mikpe/gcc-4.4-20100921/gcc/c-pch.c:420
#16 0x00574a8c in should_stack_file (import=<value optimized out>, file=<value
optimized out>, 
    pfile=<value optimized out>) at
/home/mikpe/gcc-4.4-20100921/libcpp/files.c:710
#17 _cpp_stack_file (import=<value optimized out>, file=<value optimized out>, 
    pfile=<value optimized out>) at
/home/mikpe/gcc-4.4-20100921/libcpp/files.c:795
#18 0x0056c168 in do_include_common (pfile=0x134f170, type=IT_INCLUDE)
    at /home/mikpe/gcc-4.4-20100921/libcpp/directives.c:784
#19 0x0056d028 in _cpp_handle_directive (pfile=0x134f170, indented=<value
optimized out>)
    at /home/mikpe/gcc-4.4-20100921/libcpp/directives.c:488
#20 0x00579d60 in _cpp_lex_token (pfile=0x134f170) at
/home/mikpe/gcc-4.4-20100921/libcpp/lex.c:1265
#21 0x0057d3bc in cpp_get_token (pfile=0x134f170) at
/home/mikpe/gcc-4.4-20100921/libcpp/macro.c:1235
#22 0x0057d620 in cpp_get_token_with_location (pfile=0x5ca9f0, loc=0xa1000)
    at /home/mikpe/gcc-4.4-20100921/libcpp/macro.c:1347
#23 0x0000c750 in c_lex_with_flags (value=0xbe88bf20, loc=0xbe88bf24,
cpp_flags=0x0, lex_flags=0)
    at /home/mikpe/gcc-4.4-20100921/gcc/c-lex.c:306
#24 0x00055114 in c_lex_one_token (parser=0xbe88bf1c, token=0xbe88bf1c)
    at /home/mikpe/gcc-4.4-20100921/gcc/c-parser.c:201
#25 0x000628c0 in c_parser_peek_token (parser=<value optimized out>,
parser=<value optimized out>)
    at /home/mikpe/gcc-4.4-20100921/gcc/c-parser.c:310
#26 c_parse_file (parser=<value optimized out>, parser=<value optimized out>)
    at /home/mikpe/gcc-4.4-20100921/gcc/c-parser.c:8324
#27 0x00049e3c in c_common_parse_file (set_yydebug=<value optimized out>)
    at /home/mikpe/gcc-4.4-20100921/gcc/c-opts.c:1252
#28 0x00263e24 in compile_file () at
/home/mikpe/gcc-4.4-20100921/gcc/toplev.c:970
#29 do_compile () at /home/mikpe/gcc-4.4-20100921/gcc/toplev.c:2197
---Type <return> to continue, or q <return> to quit---
#30 toplev_main () at /home/mikpe/gcc-4.4-20100921/gcc/toplev.c:2229
#31 0x4018c3e0 in __libc_start_main () from /lib/libc.so.6
#32 0x0000aef0 in _start ()

Note #13.  Apparently gcc "had to relocate PCH" (whatever that means) and
tries to issue a diagnostic, which fails miserably in linemap_lookup.

I also noticed many kernel messages about alignment traps in cc1, with PC
values in linemap_lookup().

I'll try to bisect the 2.6.36-rc kernel changes to see what caused the PCH
breakage.  But even if this turns out to be a kernel bug (as opposed to the
kernel just doing something different but valid), I don't think it's Ok for gcc
to SEGV if it "had to relocate PCH".

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2010-10-12 08:35:52 UTC ---
Most likely when the linux arm kernel decided to randomize the heap.

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

--- Comment #2 from Mikael Pettersson <mikpe at it dot uu.se> 2010-10-12 10:56:39 UTC ---
I assume other Linux archs already randomize the heap.  If so, why would that
cause PCH failures on ARM?  Could it be because there's no TRY_EMPTY_VM_SPACE
definition in gcc/config/host-linux.c for ARM?

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> 2010-10-12 19:05:53 UTC ---
(In reply to comment #2)
> I assume other Linux archs already randomize the heap. 
 Could it be because there's no TRY_EMPTY_VM_SPACE definition in
gcc/config/host-linux.c for ARM?

yes, a definition for TRY_EMPTY_VM_SPACE is needed for ARM.  I just went
through this for MIPS but I have not pushed it because I don't currently have a
correct copyright assignment on file.

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

--- Comment #4 from Mikael Pettersson <mikpe at it dot uu.se> 2010-10-12 19:26:17 UTC ---
Ok.  I'll cook something up for TRY_EMPTY_VM_SPACE on ARM.

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

--- Comment #5 from Mikael Pettersson <mikpe at it dot uu.se> 2010-10-13 13:57:28 UTC ---
(In reply to comment #1)
> Most likely when the linux arm kernel decided to randomize the heap.

Confirmed.  Bisection of the kernel identified:

From: Nicolas Pitre <nico@fluxnic.net>
Date: Tue, 15 Jun 2010 01:16:19 +0000 (-0400)
Subject: [ARM] add address randomization to mmap()
X-Git-Tag: v2.6.36-rc1~591^2^2~6^2~2
X-Git-Url:
http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=cc92c28b2db5b406657ecc05235d4ca4e222ae34

[ARM] add address randomization to mmap()

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
---

diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index f5abc51..4f5b396 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -7,6 +7,7 @@
 #include <linux/shm.h>
 #include <linux/sched.h>
 #include <linux/io.h>
+#include <linux/random.h>
 #include <asm/cputype.h>
 #include <asm/system.h>

@@ -80,6 +81,9 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
                start_addr = addr = TASK_UNMAPPED_BASE;
                mm->cached_hole_size = 0;
        }
+       /* 8 bits of randomness in 20 address space bits */
+       if (current->flags & PF_RANDOMIZE)
+               addr += (get_random_int() % (1 << 8)) << PAGE_SHIFT;

 full_search:
        if (do_align)

as the cause of this regression.  Still, I think the kernel is Ok and it's
really gcc's pch implementation which is broken.

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

--- Comment #6 from Mikael Pettersson <mikpe at it dot uu.se> 2010-10-13 14:02:00 UTC ---
Created attachment 22030
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22030
define TRY_EMPTY_VM_SPACE for ARM

Preliminary patch which defines TRY_EMPTY_VM_SPACE for ARM and fixes the PCH
regressions in a PCH-only test run.  I'll submit it after some more testing.

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

--- Comment #7 from Mikael Pettersson <mikpe at it dot uu.se> 2010-10-26 19:45:30 UTC ---
The patch tested ok and has now been submitted:
http://gcc.gnu.org/ml/gcc-patches/2010-10/msg02252.html

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[ibolton at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

Ian Bolton <ibolton at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2011.01.07 11:49:35
                 CC|                            |ibolton at gcc dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #8 from Ian Bolton <ibolton at gcc dot gnu.org> 2011-01-07 11:49:35 UTC ---
Please can you confirm that this is now fixed in trunk, Mikael.

And has it been backported?

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

--- Comment #9 from Mikael Pettersson <mikpe at it dot uu.se> 2011-01-10 19:30:30 UTC ---
(In reply to comment #8)
> Please can you confirm that this is now fixed in trunk, Mikael.

No, it has not been fixed on trunk.

> And has it been backported?

Not in the official gcc repository.  I do use the fix in my private 4.4 and 4.5
based compilers.

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[ramana at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

--- Comment #10 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> 2011-05-05 09:52:18 UTC ---
Author: ramana
Date: Thu May  5 09:52:12 2011
New Revision: 173421

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=173421
Log:

For Michael Hope.

2011-05-05  Michael Hope  <michael.hope@linaro.org>

       PR pch/45979
       * config/host-linux.c (TRY_EMPTY_VM_SPACE): Define for
       __ARM_EABI__ hosts.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/host-linux.c

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0

--- Comment #11 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-02-07 02:38:12 UTC ---
Fixed.

[Bug pch/45979] precompiled headers breakage on 2.6.36-rc Linux/ARM kernels

[michaelh at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45979

--- Comment #12 from michaelh at gcc dot gnu.org 2012-03-23 02:19:51 UTC ---
Author: michaelh
Date: Fri Mar 23 02:19:46 2012
New Revision: 185724

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=185724
Log:
2012-03-16  Michael Hope  <michael.hope@linaro.org>

    Backport from mainline
    2011-05-05  Michael Hope  <michael.hope@linaro.org>

    PR pch/45979
    * config/host-linux.c (TRY_EMPTY_VM_SPACE): Define for
    __ARM_EABI__ hosts.


Modified:
    branches/gcc-4_6-branch/gcc/ChangeLog
    branches/gcc-4_6-branch/gcc/config/host-linux.c