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| author | Bart Van Assche <bvanassche@acm.org> | 2022-08-22 01:05:00 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2022-09-01 08:02:10 +0300 |
| commit | 70e8d057bef5367709f4eda15b8d9a40d1b45e90 (patch) | |
| tree | 76a4f54ac584f718830ad3feaa680ce82a0a6ae8 | |
| parent | 2b36209ca8182c5e0221dd416106d434de433d34 (diff) | |
| download | linux-70e8d057bef5367709f4eda15b8d9a40d1b45e90.tar.xz | |
scsi: core: Revert "Simplify LLD module reference counting"
Revert the patch series "Call blk_mq_free_tag_set() earlier" because it
introduces a deadlock if the scsi_remove_host() caller holds a reference on
a device, target or host.
Link: https://lore.kernel.org/r/20220821220502.13685-3-bvanassche@acm.org
Fixes: 1a9283782df2 ("scsi: core: Simplify LLD module reference counting")
Reported-by: syzbot+bafeb834708b1bb750bc@syzkaller.appspotmail.com
Tested-by: Kenneth R. Crudup <kenny@panix.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| -rw-r--r-- | drivers/scsi/scsi.c | 9 | ||||
| -rw-r--r-- | drivers/scsi/scsi_sysfs.c | 9 |
2 files changed, 12 insertions, 6 deletions
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index 086ec5b5862d..c59eac7a32f2 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -586,13 +586,10 @@ EXPORT_SYMBOL(scsi_device_get); */ void scsi_device_put(struct scsi_device *sdev) { - /* - * Decreasing the module reference count before the device reference - * count is safe since scsi_remove_host() only returns after all - * devices have been removed. - */ - module_put(sdev->host->hostt->module); + struct module *mod = sdev->host->hostt->module; + put_device(&sdev->sdev_gendev); + module_put(mod); } EXPORT_SYMBOL(scsi_device_put); diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 9dad2fd5297f..282b32781e8c 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -452,6 +452,9 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) struct scsi_vpd *vpd_pg0 = NULL, *vpd_pg89 = NULL; struct scsi_vpd *vpd_pgb0 = NULL, *vpd_pgb1 = NULL, *vpd_pgb2 = NULL; unsigned long flags; + struct module *mod; + + mod = sdev->host->hostt->module; scsi_dh_release_device(sdev); @@ -518,11 +521,17 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) if (parent) put_device(parent); + module_put(mod); } static void scsi_device_dev_release(struct device *dev) { struct scsi_device *sdp = to_scsi_device(dev); + + /* Set module pointer as NULL in case of module unloading */ + if (!try_module_get(sdp->host->hostt->module)) + sdp->host->hostt->module = NULL; + execute_in_process_context(scsi_device_dev_release_usercontext, &sdp->ew); } |