From: "David S. Miller" <davem@davemloft.net>
To: torvalds@osdl.org
Cc: dwmw2@infradead.org, akpm@osdl.org, linux-kernel@vger.kernel.org
Subject: [PATCH]: Fix regression added by ppoll/pselect code.
Date: Thu, 19 Jan 2006 16:40:42 -0800 (PST) [thread overview]
Message-ID: <20060119.164042.74751188.davem@davemloft.net> (raw)
The compat layer timeout handling changes in:
9f72949f679df06021c9e43886c9191494fdb007
are busted. This is most easily seen with an X application
that uses sub-second select/poll timeout such as emacs. You
hit a key and it takes a second or so before the app responds.
The two ROUND_UP() calls upon entry are using {tv,ts}_sec where it
should instead be using {tv_usec,ts_nsec}, which perfectly explains
the observed incorrect behavior.
Another bug shot down with git bisect.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/fs/compat.c b/fs/compat.c
index 18b21b4..ff0bafc 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -1743,7 +1743,7 @@ asmlinkage long compat_sys_select(int n,
if ((u64)tv.tv_sec >= (u64)MAX_INT64_SECONDS)
timeout = -1; /* infinite */
else {
- timeout = ROUND_UP(tv.tv_sec, 1000000/HZ);
+ timeout = ROUND_UP(tv.tv_usec, 1000000/HZ);
timeout += tv.tv_sec * HZ;
}
}
@@ -1884,7 +1884,7 @@ asmlinkage long compat_sys_ppoll(struct
/* We assume that ts.tv_sec is always lower than
the number of seconds that can be expressed in
an s64. Otherwise the compiler bitches at us */
- timeout = ROUND_UP(ts.tv_sec, 1000000000/HZ);
+ timeout = ROUND_UP(ts.tv_nsec, 1000000000/HZ);
timeout += ts.tv_sec * HZ;
}
next reply other threads:[~2006-01-20 0:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-20 0:40 David S. Miller [this message]
2006-01-20 4:48 ` David Woodhouse
2006-01-20 4:56 ` Andrew Morton
2006-01-20 5:04 ` David Woodhouse
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