Messages in this thread Patch in this message | | | Date | Tue, 9 Dec 2008 11:25:12 -0500 | From | Mathieu Desnoyers <> | Subject | [PATCH] Relay : fix cpu offline problem |
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Here is a fix for how relay handles cpu hotplug in the allocation error path. If a cpu goes down while allocating, it may result in a buffer never being freed.
Lai Jiangshan originally identified this problem in the LTTng fork of relay (ltt-relay-alloc). Here is the fix which applies to the original kernel/relay.c.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> CC: Lai Jiangshan <laijs@cn.fujitsu.com> CC: Tom Zanussi <zanussi@comcast.net> --- kernel/relay.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
Index: linux-2.6-lttng/kernel/relay.c =================================================================== --- linux-2.6-lttng.orig/kernel/relay.c 2008-12-09 10:58:45.000000000 -0500 +++ linux-2.6-lttng/kernel/relay.c 2008-12-09 11:09:58.000000000 -0500 @@ -611,10 +611,9 @@ struct rchan *relay_open(const char *bas return chan; free_bufs: - for_each_online_cpu(i) { - if (!chan->buf[i]) - break; - relay_close_buf(chan->buf[i]); + for_each_possible_cpu(i) { + if (chan->buf[i]) + relay_close_buf(chan->buf[i]); } kref_put(&chan->kref, relay_destroy_channel); -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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