| Message ID | CAFULd4YwYOFh_UEKDULiB4DF56LOH8Fdzz4ybC1n-e4d7e-dpg@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
On Fri, Feb 8, 2013 at 7:23 AM, Uros Bizjak <ubizjak@gmail.com> wrote: > On Fri, Feb 8, 2013 at 4:02 PM, Ian Lance Taylor <iant@google.com> wrote: > >>>>> I did hit one new error that seems related: >>>>> >>>>> --- FAIL: TestChtimes (0.00 seconds) >>>>> os_test.go:681: AccessTime didn't go backwards; >>>>> was={63495872497 0 47130825733376}, after={63495872497 0 >>>>> 47130825733376} >>>>> os_test.go:685: ModTime didn't go backwards; was={63495872497 >>>>> 0 47130825733376}, after={63495872497 0 47130825733376} >>>>> FAIL >>>>> FAIL: os >>>> >>>> Something has gone wrong in the file >>>> libgo/go/syscall/libcall_linux_utimesnano.go. The function in that >>>> file will try utimensat. On your system that should return ENOSYS. >>>> In that case the function should convert the times and call utimes. >>>> The code looks OK to me but there may be something wrong with it. It >>>> looks like the file times didn't change at all. >>> >>> From the strace -f, it looks that utimes is not called at all in >>> between two relevant stats: >> >> Strange. What I would expect to happen is that the function in >> libcall_linux_utimesnano.go will call utimensat. Since your system >> does not have that function, that will call the stub routine in >> libgo/runtime/go-nosys.c, which will return -1 with errno set to >> ENOSYS. The code in libcall_linux_utimensnano.go will see the ENOSYS >> error and continue on to call utime. Clearly something is going wrong >> in that sequence, but I don't know what. > > Somwhow expected, following "patch" makes test to pass: > > --cut here-- > Index: go/syscall/libcall_linux_utimesnano.go > =================================================================== > --- go/syscall/libcall_linux_utimesnano.go (revision 195879) > +++ go/syscall/libcall_linux_utimesnano.go (working copy) > @@ -14,10 +14,10 @@ > if len(ts) != 2 { > return EINVAL > } > - err = utimensat(_AT_FDCWD, path, > (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0) > - if err != ENOSYS { > - return err > - } > +// err = utimensat(_AT_FDCWD, path, > (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0) > +// if err != ENOSYS { > +// return err > +// } > // If the utimensat syscall isn't available (utimensat was > added to Linux > // in 2.6.22, Released, 8 July 2007) then fall back to utimes > var tv [2]Timeval > --cut here-- > > 11491 stat("/tmp/_Go_TestChtimes581938713", {st_mode=S_IFREG|0600, > st_size=13, ...}) = 0 > 11491 rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0 > 11491 utimes("/tmp/_Go_TestChtimes581938713", {{1360336212, 0}, > {1360336212, 0}}) = 0 > 11491 rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0 > 11491 stat("/tmp/_Go_TestChtimes581938713", {st_mode=S_IFREG|0600, > st_size=13, ...}) = 0 > > It looks to me that gcc miscompiles this part for some reason...? A miscompilation seems fairly unlikely. I expect it's something very obvious, I'm just not seeing it. Can you verify that the code reaches the stub definition of utimensat in libgo/runtime/go-nosys.c? In fact, maybe if you just send me the test executable it will fail on my system. Seems worth a try. Ian
On Fri, Feb 8, 2013 at 5:21 PM, Ian Lance Taylor <iant@google.com> wrote: > On Fri, Feb 8, 2013 at 7:23 AM, Uros Bizjak <ubizjak@gmail.com> wrote: >> On Fri, Feb 8, 2013 at 4:02 PM, Ian Lance Taylor <iant@google.com> wrote: >> >>>>>> I did hit one new error that seems related: >>>>>> >>>>>> --- FAIL: TestChtimes (0.00 seconds) >>>>>> os_test.go:681: AccessTime didn't go backwards; >>>>>> was={63495872497 0 47130825733376}, after={63495872497 0 >>>>>> 47130825733376} >>>>>> os_test.go:685: ModTime didn't go backwards; was={63495872497 >>>>>> 0 47130825733376}, after={63495872497 0 47130825733376} >>>>>> FAIL >>>>>> FAIL: os >>>>> >>>>> Something has gone wrong in the file >>>>> libgo/go/syscall/libcall_linux_utimesnano.go. The function in that >>>>> file will try utimensat. On your system that should return ENOSYS. >>>>> In that case the function should convert the times and call utimes. >>>>> The code looks OK to me but there may be something wrong with it. It >>>>> looks like the file times didn't change at all. >>>> >>>> From the strace -f, it looks that utimes is not called at all in >>>> between two relevant stats: >>> >>> Strange. What I would expect to happen is that the function in >>> libcall_linux_utimesnano.go will call utimensat. Since your system >>> does not have that function, that will call the stub routine in >>> libgo/runtime/go-nosys.c, which will return -1 with errno set to >>> ENOSYS. The code in libcall_linux_utimensnano.go will see the ENOSYS >>> error and continue on to call utime. Clearly something is going wrong >>> in that sequence, but I don't know what. >> >> Somwhow expected, following "patch" makes test to pass: >> >> --cut here-- >> Index: go/syscall/libcall_linux_utimesnano.go >> =================================================================== >> --- go/syscall/libcall_linux_utimesnano.go (revision 195879) >> +++ go/syscall/libcall_linux_utimesnano.go (working copy) >> @@ -14,10 +14,10 @@ >> if len(ts) != 2 { >> return EINVAL >> } >> - err = utimensat(_AT_FDCWD, path, >> (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0) >> - if err != ENOSYS { >> - return err >> - } >> +// err = utimensat(_AT_FDCWD, path, >> (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0) >> +// if err != ENOSYS { >> +// return err >> +// } >> // If the utimensat syscall isn't available (utimensat was >> added to Linux >> // in 2.6.22, Released, 8 July 2007) then fall back to utimes >> var tv [2]Timeval >> --cut here-- >> >> 11491 stat("/tmp/_Go_TestChtimes581938713", {st_mode=S_IFREG|0600, >> st_size=13, ...}) = 0 >> 11491 rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0 >> 11491 utimes("/tmp/_Go_TestChtimes581938713", {{1360336212, 0}, >> {1360336212, 0}}) = 0 >> 11491 rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0 >> 11491 stat("/tmp/_Go_TestChtimes581938713", {st_mode=S_IFREG|0600, >> st_size=13, ...}) = 0 >> >> It looks to me that gcc miscompiles this part for some reason...? > > A miscompilation seems fairly unlikely. I expect it's something very > obvious, I'm just not seeing it. Can you verify that the code reaches > the stub definition of utimensat in libgo/runtime/go-nosys.c? utimensat returns zero on CentOS. Following is gdb session: Breakpoint 1, syscall.UtimesNano (path=..., ts.param=...) at ../../../gcc-svn/trunk/libgo/go/syscall/libcall_linux_utimesnano.go:13 13 func UtimesNano(path string, ts []Timespec) (err error) { (gdb) n 14 if len(ts) != 2 { (gdb) n 13 func UtimesNano(path string, ts []Timespec) (err error) { (gdb) n 14 if len(ts) != 2 { (gdb) n 17 err = utimensat(_AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0) (gdb) n 17 err = utimensat(_AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0) (gdb) n 18 if err != ENOSYS { (gdb) p err $1 = {__methods = 0x0, __object = 0x0} (gdb) n 19 return err (gdb) n 29 } (gdb) n os.Chtimes (name=..., atime.param=..., mtime.param=...) at file_posix.go:162 162 return nil (gdb) c Continuing. --- FAIL: TestChtimes (41.09 seconds) os_test.go:681: AccessTime didn't go backwards; was={63495938759 0 46912511898976}, after={63495938759 0 46912511898976} os_test.go:685: ModTime didn't go backwards; was={63495938759 0 46912511898976}, after={63495938759 0 46912511898976} FAIL Uros.
On Fri, Feb 8, 2013 at 8:48 AM, Uros Bizjak <ubizjak@gmail.com> wrote: > > utimensat returns zero on CentOS. Following is gdb session: Thanks--can you do the same session but with "step" instead of "next"? Ian
On Fri, Feb 8, 2013 at 5:53 PM, Ian Lance Taylor <iant@google.com> wrote: > On Fri, Feb 8, 2013 at 8:48 AM, Uros Bizjak <ubizjak@gmail.com> wrote: >> >> utimensat returns zero on CentOS. Following is gdb session: > > Thanks--can you do the same session but with "step" instead of "next"? I think I got the problem. breakpoint at utimensat (gdb) list 271 int 272 utimensat(int dirfd __attribute__ ((unused)), 273 const char *pathname __attribute__ ((unused)), 274 const struct timespec times[2] __attribute__ ((unused)), 275 int flags __attribute__ ((unused))) 276 { 277 errno = ENOSYS; 278 return -1; 279 } Breakpoint 2, utimensat (dirfd=dirfd@entry=-100, pathname=pathname@entry=0xc20064e000 "/tmp/_Go_TestChtimes925784001", times=times@entry=0xc20064e0e0, flags=flags@entry=0) at ../../../gcc-svn/trunk/libgo/runtime/go-nosys.c:276 276 { (gdb) fin Run till exit from #0 utimensat (dirfd=dirfd@entry=-100, pathname=pathname@entry=0xc20064e000 "/tmp/_Go_TestChtimes925784001", times=times@entry=0xc20064e0e0, flags=flags@entry=0) at ../../../gcc-svn/trunk/libgo/runtime/go-nosys.c:276 syscall.utimensat (dirfd=-100, flags=0, times=0xc20064e0e0, path=...) at libcalls.go:2371 2371 if _r < 0 { Value returned is $5 = -1 However, _r at call site is unsigned. (gdb) p _r $6 = 4294967295 (gdb) list 2366 } 2367 Entersyscall() 2368 _r := c_utimensat(int(dirfd), _p2, times, int(flags)) 2369 var errno Errno 2370 setErrno := false 2371 if _r < 0 { 2372 errno = GetErrno() 2373 setErrno = true 2374 } 2375 Exitsyscall() (gdb) n 2375 Exitsyscall() (gdb) n syscall.UtimesNano (path=..., ts.param=...) at ../../../gcc-svn/trunk/libgo/go/syscall/libcall_linux_utimesnano.go:18 18 if err != ENOSYS { (gdb) li 13 func UtimesNano(path string, ts []Timespec) (err error) { 14 if len(ts) != 2 { 15 return EINVAL 16 } 17 err = utimensat(_AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0) 18 if err != ENOSYS { 19 return err 20 } 21 // If the utimensat syscall isn't available (utimensat was added to Linux 22 // in 2.6.22, Released, 8 July 2007) then fall back to utimes (gdb) p err $8 = {__methods = 0x0, __object = 0x0} Uros.
Index: go/syscall/libcall_linux_utimesnano.go =================================================================== --- go/syscall/libcall_linux_utimesnano.go (revision 195879) +++ go/syscall/libcall_linux_utimesnano.go (working copy) @@ -14,10 +14,10 @@ if len(ts) != 2 { return EINVAL } - err = utimensat(_AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0) - if err != ENOSYS { - return err - } +// err = utimensat(_AT_FDCWD, path, (*[2]Timespec)(unsafe.Pointer(&ts[0])), 0) +// if err != ENOSYS { +// return err +// } // If the utimensat syscall isn't available (utimensat was