public inbox for glibc-bugs@sourceware.org help / color / mirror / Atom feed
* [Bug stdio/31183] New: Wide stream buffer size reduced MB_LEN_MAX bytes after bug 17522 fix @ 2023-12-20 15:43 fweimer at redhat dot com 2023-12-20 15:43 ` [Bug stdio/31183] " fweimer at redhat dot com ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: fweimer at redhat dot com @ 2023-12-20 15:43 UTC (permalink / raw) To: glibc-bugs https://sourceware.org/bugzilla/show_bug.cgi?id=31183 Bug ID: 31183 Summary: Wide stream buffer size reduced MB_LEN_MAX bytes after bug 17522 fix Product: glibc Version: 2.21 Status: NEW Severity: normal Priority: P2 Component: stdio Assignee: fweimer at redhat dot com Reporter: fweimer at redhat dot com Target Milestone: --- After the fix from bug 17522, we do not use the remaining buffer space if the already-written buffer space is smaller than MB_LEN_MAX (16 bytes). As we start out with no written bytes (zero), we never use the full buffer, greatly reducing performance. The fix probably explains it better: - if (fp->_IO_write_ptr - fp->_IO_write_base < sizeof (mb_buf)) + if (fp->_IO_buf_end - fp->_IO_write_ptr < sizeof (mb_buf)) { /* Make sure we have room for at least one multibyte character. */ write_ptr = write_base = mb_buf; buf_end = mb_buf + sizeof (mb_buf); } -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug stdio/31183] Wide stream buffer size reduced MB_LEN_MAX bytes after bug 17522 fix 2023-12-20 15:43 [Bug stdio/31183] New: Wide stream buffer size reduced MB_LEN_MAX bytes after bug 17522 fix fweimer at redhat dot com @ 2023-12-20 15:43 ` fweimer at redhat dot com 2023-12-20 16:17 ` fweimer at redhat dot com 2024-01-02 13:43 ` fweimer at redhat dot com 2 siblings, 0 replies; 4+ messages in thread From: fweimer at redhat dot com @ 2023-12-20 15:43 UTC (permalink / raw) To: glibc-bugs https://sourceware.org/bugzilla/show_bug.cgi?id=31183 Florian Weimer <fweimer at redhat dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |ASSIGNED Flags| |security- CC| |fweimer at redhat dot com -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug stdio/31183] Wide stream buffer size reduced MB_LEN_MAX bytes after bug 17522 fix 2023-12-20 15:43 [Bug stdio/31183] New: Wide stream buffer size reduced MB_LEN_MAX bytes after bug 17522 fix fweimer at redhat dot com 2023-12-20 15:43 ` [Bug stdio/31183] " fweimer at redhat dot com @ 2023-12-20 16:17 ` fweimer at redhat dot com 2024-01-02 13:43 ` fweimer at redhat dot com 2 siblings, 0 replies; 4+ messages in thread From: fweimer at redhat dot com @ 2023-12-20 16:17 UTC (permalink / raw) To: glibc-bugs https://sourceware.org/bugzilla/show_bug.cgi?id=31183 --- Comment #1 from Florian Weimer <fweimer at redhat dot com> --- Patch posted: [PATCH] libio: Check remaining buffer size in _IO_wdo_write (bug 31183) <https://inbox.sourceware.org/libc-alpha/87bkakx3b0.fsf@oldenburg.str.redhat.com/> -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug stdio/31183] Wide stream buffer size reduced MB_LEN_MAX bytes after bug 17522 fix 2023-12-20 15:43 [Bug stdio/31183] New: Wide stream buffer size reduced MB_LEN_MAX bytes after bug 17522 fix fweimer at redhat dot com 2023-12-20 15:43 ` [Bug stdio/31183] " fweimer at redhat dot com 2023-12-20 16:17 ` fweimer at redhat dot com @ 2024-01-02 13:43 ` fweimer at redhat dot com 2 siblings, 0 replies; 4+ messages in thread From: fweimer at redhat dot com @ 2024-01-02 13:43 UTC (permalink / raw) To: glibc-bugs https://sourceware.org/bugzilla/show_bug.cgi?id=31183 Florian Weimer <fweimer at redhat dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |FIXED Status|ASSIGNED |RESOLVED Target Milestone|--- |2.39 --- Comment #2 from Florian Weimer <fweimer at redhat dot com> --- Fixed for 2.39 via: commit ecc7c3deb9f347649c2078fcc0f94d4cedf92d60 Author: Florian Weimer <fweimer@redhat.com> Date: Tue Jan 2 14:36:17 2024 +0100 libio: Check remaining buffer size in _IO_wdo_write (bug 31183) The multibyte character needs to fit into the remaining buffer space, not the already-written buffer space. Without the fix, we were never moving the write pointer from the start of the buffer, always using the single-character fallback buffer. Fixes commit 04b76b5aa8b2d1d19066e42dd1 ("Don't error out writing a multibyte character to an unbuffered stream (bug 17522)"). -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-01-02 13:43 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2023-12-20 15:43 [Bug stdio/31183] New: Wide stream buffer size reduced MB_LEN_MAX bytes after bug 17522 fix fweimer at redhat dot com 2023-12-20 15:43 ` [Bug stdio/31183] " fweimer at redhat dot com 2023-12-20 16:17 ` fweimer at redhat dot com 2024-01-02 13:43 ` fweimer at redhat dot com
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).