Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1340018

[PATCH 17/24] staging: lustre: prevent assert on LNet module unload

Show all headers | View raw

From: Amir Shehata <amir.shehata@intel.com>

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 <amir.shehata@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6010
Reviewed-on: http://review.whamcloud.com/13110
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Doug Oucharek <doug.s.oucharek@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---
 drivers/staging/lustre/lnet/lnet/module.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/drivers/staging/lustre/lnet/lnet/module.c b/drivers/staging/lustre/lnet/lnet/module.c
index 8f053d7..e12fe37 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);
-- 
1.7.1

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 00/24] Second batch of LNet updates James Simmons <jsimmons@infradead.org> - 2016-02-22 23:30 +0100
  [PATCH 17/24] staging: lustre: prevent assert on LNet module unload James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 24/24] staging: lustre: Remove LASSERTS from router checker James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 19/24] staging: lustre: remove unnecessary EXPORT_SYMBOL from lnet layer James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 01/24] staging: lustre: Dynamic LNet Configuration (DLC) IOCTL changes James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 07/24] staging: lustre: improve LNet clean up code and API James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 23/24] staging: lustre: Use lnet_is_route_alive for router aliveness James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 22/24] staging: lustre: Allocate the correct number of rtr buffers James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 20/24] staging: lustre: avoid race during lnet acceptor thread termination James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 11/24] staging: lustre: startup lnet acceptor thread dynamically James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 09/24] staging: lustre: make some lnet functions static James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 04/24] staging: lustre: DLC user/kernel space glue code James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 13/24] staging: lustre: return -EEXIST if NI is not unique James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 03/24] staging: lustre: fix crash due to NULL networks string James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 21/24] staging: lustre: use sock.h in only acceptor.c James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 18/24] staging: lustre: remove messages from lazy portal on NI shutdown James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 05/24] staging: lustre: make local functions static for LNet ni James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 06/24] staging: lustre: remove LUSTRE_{,SRV_}LNET_PID James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 16/24] staging: lustre: assume a kernel build James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 10/24] staging: lustre: missed a few cases of using NULL instead of 0 James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 14/24] staging: lustre: handle lnet_check_routes() errors James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 08/24] staging: lustre: return appropriate errno when adding route James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100
  [PATCH 12/24] staging: lustre: reject invalid net configuration for lnet James Simmons <jsimmons@infradead.org> - 2016-02-22 23:40 +0100

csiph-web