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Re: [PATCH v2] ftell: seek to end only when there are unflushed bytes (BZ #17647)
- From: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
- To: "Carlos O'Donell" <carlos at redhat dot com>, libc-alpha at sourceware dot org
- Date: Thu, 04 Dec 2014 15:42:41 -0200
- Subject: Re: [PATCH v2] ftell: seek to end only when there are unflushed bytes (BZ #17647)
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- References: <20141125155404 dot GO12197 at spoyarek dot pnq dot redhat dot com> <547FC7C7 dot 4030000 at redhat dot com> <54805EAD dot 3000605 at linux dot vnet dot ibm dot com> <54808488 dot 1050602 at redhat dot com>
On 04-12-2014 13:58, Carlos O'Donell wrote:
> On 12/04/2014 08:16 AM, Adhemerval Zanella wrote:
>> ftell: fdopen (file, "a+"): old offset = 0, new offset = 30, offset after EOF = 36
>> ftell: fopen (file, "(null)"):
>> Program received signal SIGSEGV, Segmentation fault.
>> _IO_new_file_fopen (fp=0x212a2620, filename=0x212a0010 "/tmp/tst-active-handler-tmp.oSQlBj", mode=0x0, is32not64=1) at fileops.c:261
>> 261 switch (*mode)
>> (gdb) bt
>> #0 _IO_new_file_fopen (fp=0x212a2620, filename=0x212a0010 "/tmp/tst-active-handler-tmp.oSQlBj", mode=0x0, is32not64=1) at fileops.c:261
>> #1 0x00003fffb7e7ee7c in __fopen_internal (filename=0x212a0010 "/tmp/tst-active-handler-tmp.oSQlBj", mode=0x0, is32=<optimized out>) at iofopen.c:86
>> #2 0x00003fffb7e7ef14 in _IO_new_fopen (filename=<optimized out>, mode=<optimized out>) at iofopen.c:97
>> #3 0x0000000010001f88 in ?? ()
>> #4 0x000000001000323c in ?? ()
>> #5 0x000000001000180c in ?? ()
>> #6 0x00003fffb7e2436c in generic_start_main (main=0x10015178, argc=<optimized out>, argv=0x3fffffffeb30, auxvec=0x3fffffffece0, init=<optimized out>, rtld_fini=<optimized out>,
>> stack_end=<optimized out>, fini=<optimized out>) at ../csu/libc-start.c:289
>> #7 0x00003fffb7e24594 in __libc_start_main (argc=<optimized out>, argv=<optimized out>, ev=<optimized out>, auxvec=<optimized out>, rtld_fini=<optimized out>, stinfo=<optimized out>,
>> stack_on_entry=<optimized out>) at ../sysdeps/unix/sysv/linux/powerpc/libc-start.c:80
>> #8 0x0000000000000000 in ?? ()
>>
>> GLIBC built with GCC 4.9.3 / -O3 (I have not tested different compiler/flags). I tried to
>> debug a little and seems the test_modes is bogus somehow. The testcase also fails running
>> on system GLIBC (2.17/FC19 in my environment).
> We would have seen this in our internal ppc/ppc64 builds, but we didn't
> which means it is likely compiler dependent.
>
> I assume that when you say FC19 you still mean a ppc64 FC19? Similar
> compiler issue?
>
> I've kicked off a ppc64le build of master to see what I can see.
I also thinks it is a codegen issue I am seeing, although valgrind did not report
any meaningful issue besides the invalid memory access itself. I will check more
today.
> Cheers,
> Carlos.
>