Messages in this thread | | | Date | Tue, 17 Sep 2013 16:30:43 -0400 | From | Peter Hurley <> | Subject | Re: [PATCH 1/1] tty: disassociate_ctty() sends the extra SIGCONT |
| |
On 09/17/2013 03:41 PM, Carlos O'Donell wrote: > On 09/16/2013 06:16 PM, Peter Hurley wrote: >> On 09/15/2013 11:50 AM, Oleg Nesterov wrote: >>> Starting from v3.10 (probably f91e2590 "tty: Signal foreground >>> group processes in hangup") disassociate_ctty() sends SIGCONT >>> if tty && on_exit. This breaks LSB test-suite, in particular >>> test8 in _exit.c and test40 in sigcon5.c. >>> >>> Put the "!on_exit" check back to restore the old behaviour. >>> >>> Cc: stable@vger.kernel.org # v3.10+ >>> Signed-off-by: Oleg Nesterov <oleg@redhat.com> >>> Reported-by: Karel Srot <ksrot@redhat.com> >> >> Although I confirmed your results with a new unit test, >> I'd like to review the source code for the reported tests. >> Where can grab the source for the LSB tests, _exit.c and sigcon5.c? >> Direct links would be appreciated. > > wget ftp://ftp.linuxfoundation.org/pub/lsb/test_suites/released-4.1/source/runtime/lsb-test-core-4.1.15-1.src.rpm > rpm2cpio lsb-test-core-4.1.15-1.src.rpm | cpio -idmv > tar zxvf lsb-test-core-4.1.15.tar.gz > tar zxvf lts_vsx-pcts-4.1.15.tgz > > Source is at: > ./tset/POSIX.os/procprim/_exit/_exit.c > ./tset/POSIX.os/procprim/sigconcept/sigcon5.c
Hi Carlos,
Thanks for the links.
> In all failures the tests are checking for SIGHUP to be sent > to a foreground process. It would appear that the additional > signal confuses the test. > > Exactly what semantics should be followed do not seem to be > clearly covered by any standards. > > Therefore it is likely just as valid to say that the LSB tests > need to be more robust in the face of the additional signal. > > I have little experience when it comes this particular area > of the kernel or expected behaviour from other OSs.
The _exit.c:test8() and sigcon5.c:test40() look correct to me. The fact that they are fragile IMO is a good thing; I could easily envision an app's signal handling being equally fragile.
Although SUSv3 & v4 don't preclude the extra SIGCONT, in this specific case, a pty should receive the same signals, in the same order as a regular tty.
Thanks again, Peter Hurley
| |