scsi: storvsc: Ratelimit warning logs to prevent VM denial of service

commit d2138eab8cde61e0e6f62d0713e45202e8457d6d upstream

If there's a persistent error in the hypervisor, the SCSI warning for failed I/O can flood the kernel log and max out CPU utilization, preventing troubleshooting from the VM side. Ratelimit the warning so it doesn't DoS the VM.

---
 drivers/scsi/storvsc_drv.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

index 0685cbe7f0eb..d47adab00f04 100644
@@ -171,6 +171,12 @@ do {								\
 		dev_warn(&(dev)->device, fmt, ##__VA_ARGS__);	\
 } while (0)
 
+#define storvsc_log_ratelimited(dev, level, fmt, ...)				\
+do {										\
+	if (do_logging(level))							\
+		dev_warn_ratelimited(&(dev)->device, fmt, ##__VA_ARGS__);	\
+} while (0)
+
 struct vmscsi_request {
 	u16 length;
 	u8 srb_status;

@@ -1168,7 +1174,7 @@ static void storvsc_on_io_completion(struct storvsc_device *stor_device,
 		int loglevel = (stor_pkt->vm_srb.cdb[0] == TEST_UNIT_READY) ?
 			STORVSC_LOGGING_WARN : STORVSC_LOGGING_ERROR;
 
-		storvsc_log(device, loglevel,
+		storvsc_log_ratelimited(device, loglevel,
 			"tag#%d cmd 0x%x status: scsi 0x%x srb 0x%x hv 0x%x\n",
 			scsi_cmd_to_rq(request->cmd)->tag,
 			stor_pkt->vm_srb.cdb[0],

2.43.0

[ Sasha's backport helper bot ]

Hi,

The upstream commit SHA1 provided is correct: d2138eab8cde61e0e6f62d0713e45202e8457d6d

Status in newer kernel trees:
6.13.y | Branch not found
6.12.y | Not found
6.6.y | Not found
6.1.y | Not found

Note: The patch differs from the upstream commit:
---
1: d2138eab8cde6 ! 1: 3683115b8be9f scsi: storvsc: Ratelimit warning logs to prevent VM denial of service
@@ Metadata
## Commit message ##
scsi: storvsc: Ratelimit warning logs to prevent VM denial of service

+ commit d2138eab8cde61e0e6f62d0713e45202e8457d6d upstream
+
If there's a persistent error in the hypervisor, the SCSI warning for failed I/O can flood the kernel log and max out CPU utilization, preventing troubleshooting from the VM side. Ratelimit the warning so
@@ Commit message

+ Signed-off-by: Easwar Hariharan <[email protected]>

## drivers/scsi/storvsc_drv.c ##
@@ drivers/scsi/storvsc_drv.c: do { \
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y        |  Success    |  Success   |