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bpo-32186: Release the GIL during lseek and fstat (#4652) 

In _io_FileIO_readall_impl(), lseek() and _Py_fstat_noraise() were called
without releasing the GIL. This can cause all threads to hang for
unlimited time when calling FileIO.read() and the NFS server is not
accessible.
This commit is contained in:
Nir Soffer 2017-12-01 03:18:58 +02:00 committed by Victor Stinner
parent c319eeeb45
commit 6a89481680
2 changed files with 8 additions and 1 deletions
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3
Misc/NEWS.d/next/Library/2017-11-30-20-38-16.bpo-32186.O42bVe.rst Normal file
View File

@ -0,0 +1,3 @@
io.FileIO.readall() and io.FileIO.read() now release the GIL when
getting the file size. Fixed hang of all threads with inaccessible NFS
server. Patch by Nir Soffer.

6
Modules/_io/fileio.c
View File

@ -683,10 +683,12 @@ _io_FileIO_readall_impl(fileio *self)
Py_ssize_t bytes_read = 0;
Py_ssize_t n;
size_t bufsize;
int fstat_result;
if (self->fd < 0)
return err_closed();
Py_BEGIN_ALLOW_THREADS
_Py_BEGIN_SUPPRESS_IPH
#ifdef MS_WINDOWS
pos = _lseeki64(self->fd, 0L, SEEK_CUR);
@ -694,8 +696,10 @@ _io_FileIO_readall_impl(fileio *self)
pos = lseek(self->fd, 0L, SEEK_CUR);
#endif
_Py_END_SUPPRESS_IPH
fstat_result = _Py_fstat_noraise(self->fd, &status);
Py_END_ALLOW_THREADS
if (_Py_fstat_noraise(self->fd, &status) == 0)
if (fstat_result == 0)
end = status.st_size;
else
end = (Py_off_t)-1;