2019-12-10 14:22:01

by Arne Jansen

[permalink] [raw]
Subject: [PATCH] scsi_lib: ratelimit printk in scsi_prep_state_check

scsi_prep_state_check is called with the queue_lock held, called from
scsi_internal_device_unblock.
The same lock is also acquired in softirq context from scsi_end_request.
If the output overwhelms the serial console, the machine effectively
comes to a halt, even triggering a hardware watchdog.

This patch ratelimits the output.

Signed-off-by: Arne Jansen <[email protected]>
---
drivers/scsi/scsi_lib.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 3e7a45d0daca..33432108d6aa 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1232,6 +1232,10 @@ static blk_status_t scsi_setup_cmnd(struct
scsi_device *sdev,
static blk_status_t
scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
{
+ static DEFINE_RATELIMIT_STATE(_rs,
+ DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+
switch (sdev->sdev_state) {
case SDEV_OFFLINE:
case SDEV_TRANSPORT_OFFLINE:
@@ -1240,16 +1244,18 @@ scsi_prep_state_check(struct scsi_device *sdev,
struct request *req)
* commands. The device must be brought online
* before trying any recovery commands.
*/
- sdev_printk(KERN_ERR, sdev,
- "rejecting I/O to offline device\n");
+ if (__ratelimit(&_rs))
+ sdev_printk(KERN_ERR, sdev,
+ "rejecting I/O to offline device\n");
return BLK_STS_IOERR;
case SDEV_DEL:
/*
* If the device is fully deleted, we refuse to
* process any commands as well.
*/
- sdev_printk(KERN_ERR, sdev,
- "rejecting I/O to dead device\n");
+ if (__ratelimit(&_rs))
+ sdev_printk(KERN_ERR, sdev,
+ "rejecting I/O to dead device\n");
return BLK_STS_IOERR;
case SDEV_BLOCK:
case SDEV_CREATED_BLOCK:
--
2.11.0