The patch titled
proc: loadavg reading race
has been removed from the -mm tree. Its filename was
proc-loadavg-reading-race.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: proc: loadavg reading race
From: Michal Schmidt <[EMAIL PROTECTED]>
The avenrun[] values are supposed to be protected by xtime_lock.
loadavg_read_proc does not use it. Theoretically this may result in an
occasional glitch when the value read from /proc/loadavg would be as much
as 1<<11 times higher than it should be.
Signed-off-by: Michal Schmidt <[EMAIL PROTECTED]>
Cc: Thomas Gleixner <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
---
fs/proc/proc_misc.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff -puN fs/proc/proc_misc.c~proc-loadavg-reading-race fs/proc/proc_misc.c
--- a/fs/proc/proc_misc.c~proc-loadavg-reading-race
+++ a/fs/proc/proc_misc.c
@@ -84,10 +84,15 @@ static int loadavg_read_proc(char *page,
{
int a, b, c;
int len;
+ unsigned long seq;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+ a = avenrun[0] + (FIXED_1/200);
+ b = avenrun[1] + (FIXED_1/200);
+ c = avenrun[2] + (FIXED_1/200);
+ } while (read_seqretry(&xtime_lock, seq));
- a = avenrun[0] + (FIXED_1/200);
- b = avenrun[1] + (FIXED_1/200);
- c = avenrun[2] + (FIXED_1/200);
len = sprintf(page,"%d.%02d %d.%02d %d.%02d %ld/%d %d\n",
LOAD_INT(a), LOAD_FRAC(a),
LOAD_INT(b), LOAD_FRAC(b),
_
Patches currently in -mm which might be from [EMAIL PROTECTED] are
origin.patch
-
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