From: Tom Zanussi <zanussi@us.ibm.com>
This patch fails writes larger than the sub-buffer size and prints a
warning and stack trace when it happens. I chose this over BUG_ON() or
silently failing since while it could probably be considered a bug for an
application to let this happen, it's not fatal and the user would probably
want to know (and change buffer sizes).
Signed-off-by: Tom Zanussi <zanussi@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/fs/relayfs/relay.c | 13 ++++++++++++-
1 files changed, 12 insertions(+), 1 deletion(-)
diff -puN fs/relayfs/relay.c~relayfs-properly-handle-oversized-events fs/relayfs/relay.c
--- 25/fs/relayfs/relay.c~relayfs-properly-handle-oversized-events Thu Mar 24 16:15:40 2005
+++ 25-akpm/fs/relayfs/relay.c Thu Mar 24 16:15:40 2005
@@ -378,7 +378,10 @@ unsigned relay_switch_subbuf(struct rcha
int new, old, produced = atomic_read(&buf->subbufs_produced);
unsigned padding;
- if (atomic_read(&buf->unfull)) {
+ if (unlikely(length > buf->chan->subbuf_size))
+ goto toobig;
+
+ if (unlikely(atomic_read(&buf->unfull))) {
atomic_set(&buf->unfull, 0);
new = produced % buf->chan->n_subbufs;
old = (produced - 1) % buf->chan->n_subbufs;
@@ -410,7 +413,15 @@ unsigned relay_switch_subbuf(struct rcha
new = (produced + 1) % buf->chan->n_subbufs;
do_switch(buf, new, old);
+ if (unlikely(length + buf->offset > buf->chan->subbuf_size))
+ goto toobig;
+
return length;
+
+toobig:
+ printk(KERN_WARNING "relayfs: event too large (%u)\n", length);
+ WARN_ON(1);
+ return 0;
}
/**
_