Remove the /proc/scsi/${proc_name} directory earlier to fix a race
condition between unloading and reloading kernel modules. This patch
fixes a bug introduced in 2009 by patch "[SCSI] fix /proc memory leak
in the SCSI core".
This patch fixes the following kernel warning:
proc_dir_entry 'scsi/scsi_debug' already registered
WARNING: CPU: 19 PID: 27986 at fs/proc/generic.c:376 proc_register+0x27d/0x2e0
Call Trace:
proc_mkdir+0xb5/0xe0
scsi_proc_hostdir_add+0xb5/0x170
scsi_host_alloc+0x683/0x6c0
sdebug_driver_probe+0x6b/0x2d0 [scsi_debug]
really_probe+0x159/0x540
__driver_probe_device+0xdc/0x230
driver_probe_device+0x4f/0x120
__device_attach_driver+0xef/0x180
bus_for_each_drv+0xe5/0x130
__device_attach+0x127/0x290
device_initial_probe+0x17/0x20
bus_probe_device+0x110/0x130
device_add+0x673/0xc80
device_register+0x1e/0x30
sdebug_add_host_helper+0x1a7/0x3b0 [scsi_debug]
scsi_debug_init+0x64f/0x1000 [scsi_debug]
do_one_initcall+0xd7/0x470
do_init_module+0xe7/0x330
load_module+0x122a/0x12c0
__do_sys_finit_module+0x124/0x1a0
__x64_sys_finit_module+0x46/0x50
do_syscall_64+0x38/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
Reported-by: Yi Zhang <yi.zhang@xxxxxxxxxx>
Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cc: Yi Zhang <yi.zhang@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
drivers/scsi/hosts.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index b28375f9e019..f7f62e56afca 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -181,6 +181,7 @@ void scsi_remove_host(struct Scsi_Host *shost)
scsi_forget_host(shost);
mutex_unlock(&shost->scan_mutex);
scsi_proc_host_rm(shost);
+ scsi_proc_hostdir_rm(shost->hostt);
/*
* New SCSI devices cannot be attached anymore because of the SCSI host
@@ -340,6 +341,7 @@ static void scsi_host_dev_release(struct device *dev)
struct Scsi_Host *shost = dev_to_shost(dev);
struct device *parent = dev->parent;
+ /* In case scsi_remove_host() has not been called. */
scsi_proc_hostdir_rm(shost->hostt);
/* Wait for functions invoked through call_rcu(&scmd->rcu, ...) */
