Messages in this thread | | | Date | Wed, 25 Sep 2013 09:52:33 -0400 | From | Peter Hurley <> | Subject | Re: [REGRESSION][BISECTED] 3.12-rc "n_tty: Don't wait for buffer work in read() loop" patch breaks gcc's testsuite |
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[ +cc Greg Kroah-Hartman ]
On 09/25/2013 09:50 AM, Peter Hurley wrote: > On 09/25/2013 08:18 AM, Mikael Pettersson wrote: >> With 3.12-rc[12] I see unexpected failures in gcc's Ada acats testsuite, e.g. >> >> === acats tests === >> FAIL: a83009b >> FAIL: c37209a >> FAIL: c45531e >> FAIL: c45614a >> FAIL: c67005d >> FAIL: c730a01 >> FAIL: c74302b >> FAIL: cc3004a >> FAIL: cd2a24j >> FAIL: cd2a53a >> FAIL: cxa3001 >> FAIL: cxf3a07 >> FAIL: cxf3a08 >> >> === acats Summary === >> # of expected passes 2307 >> # of unexpected failures 13 >> Native configuration is x86_64-unknown-linux-gnu > > Thanks for the report. > Would you please send me the acats.log file from a failed testsuite run with its > matching screen output? > > Regards, > Peter Hurley > > >> The exact failures vary from run to run, but some failures always occur on my >> x86_64 machines, and all three open gcc branches (trunk, 4.8, 4.7) are affected. >> With a 3.11 kernel the acats testsuite is always clean. >> >> A bisection identified: >> >> From f95499c3030fe1bfad57745f2db1959c5b43dca8 Mon Sep 17 00:00:00 2001 >> From: Peter Hurley <peter@hurleysoftware.com> >> Date: Sat, 15 Jun 2013 13:14:29 +0000 >> Subject: n_tty: Don't wait for buffer work in read() loop >> >> User-space read() can run concurrently with receiving from device; >> waiting for receive_buf() to complete is not required. >> >> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> >> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >> --- >> diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c >> index fe1c399..a6eea30 100644 >> --- a/drivers/tty/n_tty.c >> +++ b/drivers/tty/n_tty.c >> @@ -1724,7 +1724,6 @@ static inline int input_available_p(struct tty_struct *tty, int amt) >> { >> struct n_tty_data *ldata = tty->disc_data; >> >> - tty_flush_to_ldisc(tty); >> if (ldata->icanon && !L_EXTPROC(tty)) { >> if (ldata->canon_head != ldata->read_tail) >> return 1; >> >> as the culprit. Reverting that from 3.12-rc2 eliminates the acats failures >> and brings the gcc testsuite results to what one gets with 3.11. >> >> I can't pretend to understand exactly what goes wrong, suffice it to say that >> the gcc testsuite harness uses a combination of shell, expect, and tcl. I >> suspect ptys are also involved. >> >> To repeat, bootstrap a recent gcc 4.8 snapshot w/ ada in --enable-languages, >> then run the test suite with "make -j6 -k check; make mail-report.log". >> (Adjust -jN as appropriate, but -j6 is what I'm using on my quad-core i7s.) >> >> Please consider reverting or fixing this patch. >> >> /Mikael
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