Date: Tue, 5 Mar 2019 19:37:07 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r344819 - stable/12/sys/kern Message-ID: <201903051937.x25Jb7jB079186@repo.freebsd.org>
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Author: markj Date: Tue Mar 5 19:37:06 2019 New Revision: 344819 URL: https://svnweb.freebsd.org/changeset/base/344819 Log: MFC r344278: Move a racy assertion in filt_pipewrite(). PR: 235640 Modified: stable/12/sys/kern/sys_pipe.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/kern/sys_pipe.c ============================================================================== --- stable/12/sys/kern/sys_pipe.c Tue Mar 5 19:17:24 2019 (r344818) +++ stable/12/sys/kern/sys_pipe.c Tue Mar 5 19:37:06 2019 (r344819) @@ -1743,15 +1743,19 @@ static int filt_pipewrite(struct knote *kn, long hint) { struct pipe *wpipe; - + + /* + * If this end of the pipe is closed, the knote was removed from the + * knlist and the list lock (i.e., the pipe lock) is therefore not held. + */ wpipe = kn->kn_hook; - PIPE_LOCK_ASSERT(wpipe, MA_OWNED); if (wpipe->pipe_present != PIPE_ACTIVE || (wpipe->pipe_state & PIPE_EOF)) { kn->kn_data = 0; kn->kn_flags |= EV_EOF; return (1); } + PIPE_LOCK_ASSERT(wpipe, MA_OWNED); kn->kn_data = (wpipe->pipe_buffer.size > 0) ? (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) : PIPE_BUF; if (wpipe->pipe_state & PIPE_DIRECTW)
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