diff options
| author | Tom Zanussi <zanussi@us.ibm.com> | 2005-12-20 13:10:22 -0600 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-12-20 17:33:22 -0800 |
| commit | fd30fc3256824f03c2ff9317269d66f72f7042ca (patch) | |
| tree | 863a1ba4ddae961e2727343c17d15f64c3f4d463 | |
| parent | bb44f116a14c4c932f15c79acfafd46bcb43ca9a (diff) | |
[PATCH] relayfs: remove warning printk() in relay_switch_subbuf()
There's currently a diagnostic printk in relay_switch_subbuf() meant as
a warning if you accidentally try to log an event larger than the
sub-buffer size.
The problem is if this happens while logging from somewhere it's not
safe to be doing printks, such as in the scheduler, you can end up with
a deadlock. This patch removes the warning from relay_switch_subbuf()
and instead prints some diagnostic info when the channel is closed.
Thanks to Mathieu Desnoyers for pointing out the problem and
suggesting a fix.
Signed-off-by: Tom Zanussi <zanussi@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | fs/relayfs/relay.c | 8 | ||||
| -rw-r--r-- | include/linux/relayfs_fs.h | 5 |
2 files changed, 9 insertions, 4 deletions
diff --git a/fs/relayfs/relay.c b/fs/relayfs/relay.c index 16446a15c96..2a6f7f12b7f 100644 --- a/fs/relayfs/relay.c +++ b/fs/relayfs/relay.c @@ -333,8 +333,7 @@ size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length) return length; toobig: - printk(KERN_WARNING "relayfs: event too large (%Zd)\n", length); - WARN_ON(1); + buf->chan->last_toobig = length; return 0; } @@ -399,6 +398,11 @@ void relay_close(struct rchan *chan) relay_close_buf(chan->buf[i]); } + if (chan->last_toobig) + printk(KERN_WARNING "relayfs: one or more items not logged " + "[item size (%Zd) > sub-buffer size (%Zd)]\n", + chan->last_toobig, chan->subbuf_size); + kref_put(&chan->kref, relay_destroy_channel); } diff --git a/include/linux/relayfs_fs.h b/include/linux/relayfs_fs.h index cfafc3e76bc..fb7e8073732 100644 --- a/include/linux/relayfs_fs.h +++ b/include/linux/relayfs_fs.h @@ -20,9 +20,9 @@ #include <linux/kref.h> /* - * Tracks changes to rchan_buf struct + * Tracks changes to rchan/rchan_buf structs */ -#define RELAYFS_CHANNEL_VERSION 5 +#define RELAYFS_CHANNEL_VERSION 6 /* * Per-cpu relay channel buffer @@ -60,6 +60,7 @@ struct rchan struct rchan_callbacks *cb; /* client callbacks */ struct kref kref; /* channel refcount */ void *private_data; /* for user-defined data */ + size_t last_toobig; /* tried to log event > subbuf size */ struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */ }; |