Avoid that disk probing hangs as follows if a SCSI host is removed after disk scanning started and before it completed:
Call Trace: __schedule+0x2fa/0xbb0 schedule+0x36/0x90 schedule_timeout+0x22c/0x570 io_schedule_timeout+0x1e/0x50 wait_for_completion_io_timeout+0x11f/0x180 blk_execute_rq+0x86/0xc0 scsi_execute+0xdb/0x1f0 sd_revalidate_disk+0xed/0x1c70 [sd_mod] sd_probe_async+0xc3/0x1d0 [sd_mod] async_run_entry_fn+0x38/0x160 process_one_work+0x20a/0x660 worker_thread+0x3d/0x3b0 kthread+0x13a/0x150 ret_from_fork+0x27/0x40 Signed-off-by: Bart Van Assche <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Hannes Reinecke <[email protected]> Cc: Johannes Thumshirn <[email protected]> --- drivers/scsi/sd.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 0313486d85c8..d5e2b73c02ea 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -3225,11 +3225,13 @@ static void sd_probe_async(void *data, async_cookie_t cookie) { struct scsi_disk *sdkp = data; struct scsi_device *sdp; + struct Scsi_Host *host; struct gendisk *gd; u32 index; struct device *dev; sdp = sdkp->device; + host = sdp->host; gd = sdkp->disk; index = sdkp->index; dev = &sdp->sdev_gendev; @@ -3253,6 +3255,13 @@ static void sd_probe_async(void *data, async_cookie_t cookie) sdkp->first_scan = 1; sdkp->max_medium_access_timeouts = SD_MAX_MEDIUM_TIMEOUTS; + mutex_lock(&host->scan_mutex); + if (!scsi_host_scan_allowed(host)) { + sd_printk(KERN_NOTICE, sdkp, "%s: host being removed\n", + __func__); + goto unlock; + } + sd_revalidate_disk(gd); gd->flags = GENHD_FL_EXT_DEVT; @@ -3276,8 +3285,12 @@ static void sd_probe_async(void *data, async_cookie_t cookie) sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n", sdp->removable ? "removable " : ""); +unlock: + mutex_unlock(&host->scan_mutex); + scsi_host_put(host); scsi_autopm_put_device(sdp); put_device(&sdkp->dev); + return; } /** @@ -3377,7 +3390,15 @@ static int sd_probe(struct device *dev) get_device(dev); dev_set_drvdata(dev, sdkp); - get_device(&sdkp->dev); /* prevent release before async_schedule */ + /* prevent release before async_schedule */ + error = -ENODEV; + if (scsi_host_get(sdp->host) == NULL) { + sd_printk(KERN_NOTICE, sdkp, "%s: host being removed\n", + __func__); + put_device(&sdkp->dev); + goto out; + } + get_device(&sdkp->dev); async_schedule_domain(sd_probe_async, sdkp, &scsi_sd_probe_domain); return 0; -- 2.14.3
