Attachment 15058 Details for Bug 13895 – Patch for 4.9 and 4.10

[patch] Patch for 4.9 and 4.10

BZ13895.patch (text/plain), 1.72 KB, created by Martin Schwenke on 2019-04-13 02:00:02 UTC

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Creator: Martin Schwenke

Created: 2019-04-13 02:00:02 UTC

Size: 1.72 KB

patch

obsolete

>From 16bc83afa8de707e4119b178758437415857518e Mon Sep 17 00:00:00 2001
>From: Amitay Isaacs <amitay@samba.org>
>Date: Tue, 9 Apr 2019 14:44:04 +1000
>Subject: [PATCH] ctdb-common: Avoid race between fd and signal events
>
>BUG: https://bugzilla.samba.org/show_bug.cgi?id=13895
>
>In run_proc, there was an implicit assumption that when a process exits,
>fd event (pipe between parent and child) would be processed first and
>signal event (SIGCHLD for the child) would be processed later.
>
>However, that is not the case.  SIGCHLD can be received asynchronously
>any time even when the pipe data has not fully been read.  This causes
>run_proc to miss some of the output from child process in tests.
>
>When SIGCHLD is being processed, if the pipe between parent and child is
>still open, then do an explict read from the pipe to ensure we read any
>data still in the pipe before closing the pipe.
>
>Signed-off-by: Amitay Isaacs <amitay@gmail.com>
>Reviewed-by: Martin Schwenke <martin@meltin.net>
>
>Autobuild-User(master): Amitay Isaacs <amitay@samba.org>
>Autobuild-Date(master): Fri Apr 12 08:19:29 UTC 2019 on sn-devel-144
>
>(cherry picked from commit 289201277cd983b27cdfd5376c607eab112b4082)
>---
> ctdb/common/run_proc.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
>diff --git a/ctdb/common/run_proc.c b/ctdb/common/run_proc.c
>index 97895b383b9..037b6d9651d 100644
>--- a/ctdb/common/run_proc.c
>+++ b/ctdb/common/run_proc.c
>@@ -295,6 +295,13 @@ again:
> 		proc->result.sig = WTERMSIG(status);
> 	}
> 
>+	/* Confirm that all data has been read from the pipe */
>+	if (proc->fd != -1) {
>+		proc_read_handler(ev, proc->fde, 0, proc);
>+		TALLOC_FREE(proc->fde);
>+		proc->fd = -1;
>+	}
>+
> 	/* Active run_proc request */
> 	if (proc->req != NULL) {
> 		run_proc_done(proc->req);
>-- 
>2.20.1
>

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amitay: review+

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Attachments on bug 13895: 15058