From: Bart Van Assche bvanassche@acm.org
commit fc663711b94468f4e1427ebe289c9f05669699c9 upstream.
Remove the /proc/scsi/${proc_name} directory earlier to fix a race condition between unloading and reloading kernel modules. This fixes a bug introduced in 2009 by commit 77c019768f06 ("[SCSI] fix /proc memory leak in the SCSI core").
Fix 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
Link: https://lore.kernel.org/r/20230210205200.36973-3-bvanassche@acm.org Cc: Alan Stern stern@rowland.harvard.edu Cc: Yi Zhang yi.zhang@redhat.com Cc: stable@vger.kernel.org Fixes: 77c019768f06 ("[SCSI] fix /proc memory leak in the SCSI core") Reported-by: Yi Zhang yi.zhang@redhat.com Signed-off-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Nobuhiro Iwamatsu (CIP) nobuhiro1.iwamatsu@toshiba.co.jp --- drivers/scsi/hosts.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index c59b3fd6b361..7ffdebdd9c54 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -173,6 +173,7 @@ 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);
spin_lock_irqsave(shost->host_lock, flags); if (scsi_host_set_state(shost, SHOST_DEL)) @@ -322,6 +323,7 @@ static void scsi_host_dev_release(struct device *dev) struct request_queue *q; void *queuedata;
+ /* In case scsi_remove_host() has not been called. */ scsi_proc_hostdir_rm(shost->hostt);
if (shost->tmf_work_q)
On Wed, Jun 25, 2025 at 11:00:26AM +0900, Nobuhiro Iwamatsu wrote:
From: Bart Van Assche bvanassche@acm.org
commit fc663711b94468f4e1427ebe289c9f05669699c9 upstream.
Remove the /proc/scsi/${proc_name} directory earlier to fix a race condition between unloading and reloading kernel modules. This fixes a bug introduced in 2009 by commit 77c019768f06 ("[SCSI] fix /proc memory leak in the SCSI core").
Fix 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
Can you or Bart please explain in more detail the race that causes this problem, and add that description to the changelog? Also, explain how this patch fixes the race.
Alan Stern
Link: https://lore.kernel.org/r/20230210205200.36973-3-bvanassche@acm.org Cc: Alan Stern stern@rowland.harvard.edu Cc: Yi Zhang yi.zhang@redhat.com Cc: stable@vger.kernel.org Fixes: 77c019768f06 ("[SCSI] fix /proc memory leak in the SCSI core") Reported-by: Yi Zhang yi.zhang@redhat.com Signed-off-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Nobuhiro Iwamatsu (CIP) nobuhiro1.iwamatsu@toshiba.co.jp
drivers/scsi/hosts.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index c59b3fd6b361..7ffdebdd9c54 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -173,6 +173,7 @@ 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);
spin_lock_irqsave(shost->host_lock, flags); if (scsi_host_set_state(shost, SHOST_DEL)) @@ -322,6 +323,7 @@ static void scsi_host_dev_release(struct device *dev) struct request_queue *q; void *queuedata;
- /* In case scsi_remove_host() has not been called. */ scsi_proc_hostdir_rm(shost->hostt);
if (shost->tmf_work_q) -- 2.25.1
On Wed, Jun 25, 2025 at 11:00:26AM +0900, Nobuhiro Iwamatsu wrote:
From: Bart Van Assche bvanassche@acm.org
commit fc663711b94468f4e1427ebe289c9f05669699c9 upstream.
4.4.y is long out-of-support by us, and this is in all activly supported kenrnels at this time, so why is this sent to us?
confused,
greg k-h
-----Original Message----- From: Greg KH gregkh@linuxfoundation.org Sent: Wednesday, June 25, 2025 4:05 PM To: iwamatsu nobuhiro(岩松 信洋 □ＤＩＴＣ○ＣＰＴ) nobuhiro1.iwamatsu@toshiba.co.jp Cc: cip-dev@lists.cip-project.org; Ulrich Hecht uli@fpond.eu; Pavel Machek pavel@denx.de; Bart Van Assche bvanassche@acm.org; Alan Stern stern@rowland.harvard.edu; Yi Zhang yi.zhang@redhat.com; stable@vger.kernel.org; Martin K . Petersen martin.petersen@oracle.com Subject: Re: [PATCH for 4.4] scsi: core: Remove the /proc/scsi/${proc_name} directory earlier
On Wed, Jun 25, 2025 at 11:00:26AM +0900, Nobuhiro Iwamatsu wrote:
From: Bart Van Assche bvanassche@acm.org
commit fc663711b94468f4e1427ebe289c9f05669699c9 upstream.
4.4.y is long out-of-support by us, and this is in all activly supported kenrnels at this time, so why is this sent to us?
This was also sent to stable due to the processing of the patch's CC tag. I'm sorry for the confusion.
Best regards, Nobuhiro
linux-stable-mirror@lists.linaro.org
-
Alan Stern -
Greg KH -
Nobuhiro Iwamatsu -
nobuhiro1.iwamatsu＠toshiba.co.jp