2017-08-13 23:48:34 +02:00
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From a853f21633693f9eefc4949660253a5328d2d2f3 Mon Sep 17 00:00:00 2001
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From: "Yann E. MORIN" <yann.morin.1998@free.fr>
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Date: Sun, 13 Aug 2017 23:21:54 +0200
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2019-09-17 05:58:15 +02:00
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Subject: [PATCH] communicate: check return status of msgrcv()
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2017-08-13 23:48:34 +02:00
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msgrcv can return with -1 to indicate an error condition.
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One such error is to have been interrupted by a signal.
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Being interrupted by a signal is very rare in this code, except in a
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very special condition: a highly-parallel (1000 jobs!) mksquashfs on
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a filesystem with extended attributes, where we see errors like (those
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are mksquashfs errors):
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llistxattr for titi/603/883 failed in read_attrs, because Unknown
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error 1716527536
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See: https://bugs.busybox.net/show_bug.cgi?id=10141
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In this case, we just have to retry the call to msgrcv().
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Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
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---
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communicate.c | 5 ++++-
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1 file changed, 4 insertions(+), 1 deletion(-)
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diff --git a/communicate.c b/communicate.c
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index 293f404..787bb63 100644
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--- a/communicate.c
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+++ b/communicate.c
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@@ -553,10 +553,13 @@ void send_get_fakem(struct fake_msg *buf)
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l=msgrcv(msg_get,
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(struct my_msgbuf*)buf,
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sizeof(*buf)-sizeof(buf->mtype),0,0);
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- while((buf->serial!=serial)||buf->pid!=pid);
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+ while(((l==-1)&&(errno==EINTR))||(buf->serial!=serial)||buf->pid!=pid);
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semaphore_down();
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+ if(l==-1)
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+ buf->xattr.flags_rc=errno;
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+
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/*
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(nah, may be wrong, due to allignment)
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--
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2.11.0
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