From 286c171b86ebc693e18b485dde3a3fc470af37bd Mon Sep 17 00:00:00 2001 From: Dominique Martinet Date: Mon, 13 Jun 2022 08:32:06 +0900 Subject: 9p fid refcount: add a 9p_fid_ref tracepoint This adds a tracepoint event for 9p fid lifecycle tracing: when a fid is created, its reference count increased/decreased, and freed. The new 9p_fid_ref tracepoint should help anyone wishing to debug any fid problem such as missing clunk (destroy) or use-after-free. Link: https://lkml.kernel.org/r/20220612085330.1451496-6-asmadeus@codewreck.org Signed-off-by: Dominique Martinet --- net/9p/client.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) (limited to 'net/9p') diff --git a/net/9p/client.c b/net/9p/client.c index f3eb280c7d9d..dfe8beb864fc 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -907,8 +907,10 @@ static struct p9_fid *p9_fid_create(struct p9_client *clnt) GFP_NOWAIT); spin_unlock_irq(&clnt->lock); idr_preload_end(); - if (!ret) + if (!ret) { + trace_9p_fid_ref(fid, P9_FID_REF_CREATE); return fid; + } kfree(fid); return NULL; @@ -920,6 +922,7 @@ static void p9_fid_destroy(struct p9_fid *fid) unsigned long flags; p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid); + trace_9p_fid_ref(fid, P9_FID_REF_DESTROY); clnt = fid->clnt; spin_lock_irqsave(&clnt->lock, flags); idr_remove(&clnt->fids, fid->fid); @@ -928,6 +931,21 @@ static void p9_fid_destroy(struct p9_fid *fid) kfree(fid); } +/* We also need to export tracepoint symbols for tracepoint_enabled() */ +EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref); + +void do_trace_9p_fid_get(struct p9_fid *fid) +{ + trace_9p_fid_ref(fid, P9_FID_REF_GET); +} +EXPORT_SYMBOL(do_trace_9p_fid_get); + +void do_trace_9p_fid_put(struct p9_fid *fid) +{ + trace_9p_fid_ref(fid, P9_FID_REF_PUT); +} +EXPORT_SYMBOL(do_trace_9p_fid_put); + static int p9_client_version(struct p9_client *c) { int err = 0; -- cgit v1.2.3-70-g09d2