From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arseny Maslennikov Subject: Re: [PATCH v2 4/7] linux/signal.h: Ignore SIGINFO by default in new tasks Date: Mon, 29 Jul 2019 13:55:21 +0300 Message-ID: <20190729105520.GA25742@cello> References: <20190625161153.29811-1-ar@cs.msu.ru> <20190625161153.29811-5-ar@cs.msu.ru> <20190625213215.GB3116@mit.edu> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="jI8keyz6grp/JLjh" Return-path: Content-Disposition: inline In-Reply-To: <20190625213215.GB3116@mit.edu> Sender: linux-kernel-owner@vger.kernel.org To: Theodore Ts'o Cc: Greg Kroah-Hartman , Jiri Slaby , Ingo Molnar , Peter Zijlstra , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, "Vladimir D. Seleznev" , Rob Landley , "Eric W. Biederman" , Pavel Machek List-Id: linux-serial@vger.kernel.org --jI8keyz6grp/JLjh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jun 25, 2019 at 05:32:15PM -0400, Theodore Ts'o wrote: > <...> >=20 > (In particular it might be worth checking Linux ports of Oracle and > DB2.) A couple of weeks of asking around got me to have a look at a DB2 9.7 instance. sn1:~ # uname -a Linux sn1 2.6.16.60-0.54.5-ppc64 #1 SMP Fri Sep 4 01:28:03 UTC 2009 ppc64 p= pc64 ppc64 GNU/Linux That particular deployment used the following set of processes: sn1:~ # ps -eo user,ppid,pid,pgid,sid,tty,state,cmd | grep db2 | grep -v ja= va bgpsysdb 8505 672 8504 7146 ? S db2fmp ( ,0,0,0,0,0,0,0,1,0,8a6= 678,14,1e014,2,0,1,171fc0,0x110000000,0x110000000,1600000,18002,2,384f00b7 bgpsysdb 8505 687 8504 7146 ? S db2fmp ( ,0,0,0,0,0,0,0,1,0,8a6= 678,14,1e014,2,0,1,191fc0,0x110000000,0x110000000,1600000,18002,2,384f80b9 bgpsysdb 8505 4309 8504 7146 ? S db2fmp ( ,0,0,0,0,0,0,0,1,0,8a6= 678,14,1e014,2,0,1,151fc0,0x110000000,0x110000000,1600000,18002,2,6f5080c5 root 1 8505 8504 7146 ? S db2wdog 0 bgpsysdb 8505 8511 8511 7146 ? S db2sysc 0 root 8511 8512 8511 7146 ? S db2ckpwd 0 root 8511 8513 8511 7146 ? S db2ckpwd 0 root 8511 8514 8511 7146 ? S db2ckpwd 0 bgpsysdb 8505 8630 8504 7146 ? S db2acd 0 ,0,0,0,1,0,0,0,1,0,8a6= 678,14,1e014,2,0,1,11fc0,0x110000000,0x110000000,1600000,18002,2,398072 bgpsysdb 8505 15280 8504 7146 ? S db2fmp ( ,1,0,0,0,0,0,0,1,0,8a6= 678,14,1e014,2,0,1,31fc0,0x110000000,0x110000000,1600000,18002,2,bd80bb bgpsysdb 8505 16032 8504 7146 ? S db2fmp ( ,0,0,0,0,0,0,0,1,0,8a6= 678,14,1e014,2,0,1,b1fc0,0x110000000,0x110000000,1600000,18002,2,81980ba bgpsysdb 8505 16073 8504 7146 ? S db2fmp ( ,0,0,0,0,0,0,0,1,0,8a6= 678,14,1e014,2,0,1,91fc0,0x110000000,0x110000000,1600000,18002,2,12300c0 bgpsysdb 8505 17683 8504 7146 ? S db2fmp ( ,0,0,0,0,0,0,0,1,0,8a6= 678,14,1e014,2,0,1,131fc0,0x110000000,0x110000000,1600000,18002,2,248600db bgpsysdb 8505 30731 8504 7146 ? S db2fmp ( ,0,0,0,0,0,0,0,1,0,8a6= 678,14,1e014,2,0,1,f1fc0,0x110000000,0x110000000,1600000,18002,2,370080d1 None of them has a controlling tty, so ^T pressed at any tty won't send them a signal. To get an idea on how do they handle signals, we can look at /proc/*/status: sn1:~ # cat /proc/{8512,8505,687,8511}/status | egrep '^(Pid|Sig|Shd)' Pid: 687 SigQ: 0/128000 SigPnd: 0000000000000000 ShdPnd: 0000000000000000 SigBlk: 0000000000000000 SigIgn: fffffffe2bbaf007 SigCgt: 00000001c44004f8 Pid: 8505 SigQ: 0/128000 SigPnd: 0000000000000000 ShdPnd: 0000000000000000 SigBlk: fffffffe7ffbfeff SigIgn: fffffffe2fbaf007 SigCgt: 00000001c0410ef8 Pid: 8511 SigQ: 0/128000 SigPnd: 0000000000000000 ShdPnd: 0000000000000000 SigBlk: fffffffe7ffbfeff SigIgn: fffffffe23b3c005 SigCgt: 00000001dc483efa Pid: 8512 SigQ: 0/128000 SigPnd: 0000000000000000 ShdPnd: 0000000000000000 SigBlk: 0000000000000000 SigIgn: fffffffe2fbbf007 SigCgt: 00000001c0400ef8 It can be seen from the above that SIGPWR in particular is always ignored and sometimes blocked, which means its default disposition has no effect. This leads me to think that DB2 in particular would be unaffected by the patch set. p.s.: I do not have shell access to the machine, and never did; the commands cited in this email were executed by a person who does, and the output was handed back to me. --jI8keyz6grp/JLjh Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEE56JD3UKTLEu/ddrm9dQjyAYL01AFAl0+0JAACgkQ9dQjyAYL 01CzdRAAu38njim8DW61okHfX3GyhvxAvUy7Fg7QPJfoLIgFRrW+s6MB1myRyem+ rvn+XScQaSlpH5a+aa50V3l3bxRuD38WF1+hU6USyjl4Jpv+DBFH5aNmYqkQIFJ1 4yKySdyOVF+jFCIpdCihoT3nfRhim7rhd4sjlYX6zWzLEvnmsYe7zPm7BZMcNPTV wgEz/AwLXjtKCoa/W6EHQUiylutWcs0TLqMCQhYpt9p9FSg2/GmCczYGc1/SZ4en Fvjp7BMYg9Ha2rNnVHkd3QbJu6S+1eyKx5srz5x2CEuAwR3Q/ojw0f4kMJgUXqCk fqj81B9hxwXoV8f3gfhLUTmZO9tmt2hP9J9aLDFfETNxzhTs0hPdPW+7Vg3CsUQ/ /WbGu6riGUsRQkUjvRoiisIVRHthxO2g6MD0taEJx3ZBfUFEtnNfzzP6xCrrKaHY LQ59yngfVUTVkHFlK+WYEHlhLXqrRHS1Kt9LFR/k7N6o7h2RspJoEOFzTZwlwV9+ A2o4xAuUeg+3frmbUC3aWljzfet5FmSZ9And6QhtD1C40DQWVtZpitI6xWULcj1i UgLFd+/02Nu1jeDnfV1r5dWGdn1K7B1TmNJ8E0xZPwPQ+d8r3bN4Cg6lwVuz7wUp tba+wUzDoTqvjmJ6sHz5qwjBfzi+OKwBR2ip4AbkWMtY843R5lQ= =6Ez9 -----END PGP SIGNATURE----- --jI8keyz6grp/JLjh--