[PATCH AUTOSEL 6.12 1/4] scsi: storvsc: Ratelimit warning logs to prevent VM denial of service

[PATCH AUTOSEL 6.12 1/4] scsi: storvsc: Ratelimit warning logs to prevent VM denial of service

[Sasha Levin]

From: Easwar Hariharan <eahariha@linux.microsoft.com>

[ Upstream commit d2138eab8cde61e0e6f62d0713e45202e8457d6d ]

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.

Closes: https://github.com/microsoft/WSL/issues/9173
Signed-off-by: Easwar Hariharan <eahariha@linux.microsoft.com>
Link: https://lore.kernel.org/r/20250107-eahariha-ratelimit-storvsc-v1-1-7fc193d1f2b0@linux.microsoft.com
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/storvsc_drv.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index d0b55c1fa908a..b3c588b102d90 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -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;
@@ -1177,7 +1183,7 @@ 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],
-- 
2.39.5