From 341bc96085f4dfbc2427d746753faf9edf789f90 Mon Sep 17 00:00:00 2001 From: Amir Shehata Date: Mon, 22 Feb 2016 17:29:18 -0500 Subject: [PATCH] staging: lustre: prevent assert on LNet module unload There is a use case where lnet can be unloaded while there are no NIs configured. Removing lnet in this case will cause LNetFini() to be called without a prior call to LNetNIFini(). This will cause the LASSERT(the_lnet.ln_refcount == 0) to be triggered. To deal with this use case when LNet is configured a reference count on the module is taken using try_module_get(). This way LNet must be unconfigured before it could be removed; therefore avoiding the above case. When LNet is unconfigured module_put() is called to return the reference count. Signed-off-by: Amir Shehata Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6010 Reviewed-on: http://review.whamcloud.com/13110 Reviewed-by: James Simmons Reviewed-by: Doug Oucharek Reviewed-by: Oleg Drokin Signed-off-by: Greg Kroah-Hartman --- drivers/staging/lustre/lnet/lnet/module.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/staging/lustre/lnet/lnet/module.c b/drivers/staging/lustre/lnet/lnet/module.c index 8f053d75e577..e12fe373dd07 100644 --- a/drivers/staging/lustre/lnet/lnet/module.c +++ b/drivers/staging/lustre/lnet/lnet/module.c @@ -53,13 +53,21 @@ lnet_configure(void *arg) mutex_lock(&lnet_config_mutex); if (!the_lnet.ln_niinit_self) { + rc = try_module_get(THIS_MODULE); + + if (rc != 1) + goto out; + rc = LNetNIInit(LNET_PID_LUSTRE); if (rc >= 0) { the_lnet.ln_niinit_self = 1; rc = 0; + } else { + module_put(THIS_MODULE); } } +out: mutex_unlock(&lnet_config_mutex); return rc; } @@ -74,6 +82,7 @@ lnet_unconfigure(void) if (the_lnet.ln_niinit_self) { the_lnet.ln_niinit_self = 0; LNetNIFini(); + module_put(THIS_MODULE); } mutex_lock(&the_lnet.ln_api_mutex);