https://github.com/python/cpython/commit/8bcd41040a5f1f9b48a86d0e21f196e4b1f... commit: 8bcd41040a5f1f9b48a86d0e21f196e4b1f90e4b branch: 3.6 author: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> committer: Victor Stinner <victor.stinner@gmail.com> date: 2017-12-01T07:26:31+01:00 summary: bpo-32186: Release the GIL during lseek and fstat (GH-4652) (#4661) 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. (cherry picked from commit 6a89481680b921e7b317c29877bdda9a6031e5ad) files: A Misc/NEWS.d/next/Library/2017-11-30-20-38-16.bpo-32186.O42bVe.rst M Modules/_io/fileio.c diff --git a/Misc/NEWS.d/next/Library/2017-11-30-20-38-16.bpo-32186.O42bVe.rst b/Misc/NEWS.d/next/Library/2017-11-30-20-38-16.bpo-32186.O42bVe.rst new file mode 100644 index 00000000000..ea696c6098a --- /dev/null +++ b/Misc/NEWS.d/next/Library/2017-11-30-20-38-16.bpo-32186.O42bVe.rst @@ -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. diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c index 918fa577758..52cbb94b24b 100644 --- a/Modules/_io/fileio.c +++ b/Modules/_io/fileio.c @@ -691,10 +691,12 @@ _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); @@ -702,8 +704,10 @@ _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;