From 2c53d9109f077900e140edb8b766132ad93b81cc Mon Sep 17 00:00:00 2001 From: Aravind Srinivasan <raa.aars@gmail.com> Date: Thu, 2 Apr 2009 16:58:59 -0700 Subject: [PATCH] relay: fix for possible loss/corruption of produced subbufs Fix possible loss/corruption of produced subbufs in relay_subbufs_consumed(). When buf->subbufs_produced wraps around after UINT_MAX and buf->subbufs_consumed is still < UINT_MAX, the condition if (buf->subbufs_consumed > buf->subbufs_produced) will be true even for certain valid values of subbufs_consumed. This may lead to loss or corruption of produced subbufs. Signed-off-by: Aravind Srinivasan <raa.aars@gmail.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Tom Zanussi <zanussi@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --- kernel/relay.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/relay.c b/kernel/relay.c index 8f2179c8056f..e92db8c06acf 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -797,13 +797,15 @@ void relay_subbufs_consumed(struct rchan *chan, if (!chan) return; - if (cpu >= NR_CPUS || !chan->buf[cpu]) + if (cpu >= NR_CPUS || !chan->buf[cpu] || + subbufs_consumed > chan->n_subbufs) return; buf = chan->buf[cpu]; - buf->subbufs_consumed += subbufs_consumed; - if (buf->subbufs_consumed > buf->subbufs_produced) + if (subbufs_consumed > buf->subbufs_produced - buf->subbufs_consumed) buf->subbufs_consumed = buf->subbufs_produced; + else + buf->subbufs_consumed += subbufs_consumed; } EXPORT_SYMBOL_GPL(relay_subbufs_consumed); -- GitLab