* [PATCH 5.10 1/2] scsi: ufs: core: Fix task management completion
2021-11-23 12:19 [PATCH 5.10 0/2] scsi: ufs: core: Fix task management completion Adrian Hunter
@ 2021-11-23 12:19 ` Adrian Hunter
2021-11-23 12:19 ` [PATCH 5.10 2/2] scsi: ufs: core: Fix task management completion timeout race Adrian Hunter
2021-11-23 12:30 ` [PATCH 5.10 0/2] scsi: ufs: core: Fix task management completion Greg KH
2 siblings, 0 replies; 4+ messages in thread
From: Adrian Hunter @ 2021-11-23 12:19 UTC (permalink / raw)
To: stable; +Cc: Martin K . Petersen, Bart Van Assche
commit f5ef336fd2e4c36dedae4e7ca66cf5349d6fda62 upstream.
The UFS driver uses blk_mq_tagset_busy_iter() when identifying task
management requests to complete, however blk_mq_tagset_busy_iter() doesn't
work.
blk_mq_tagset_busy_iter() only iterates requests dispatched by the block
layer. That appears as if it might have started since commit 37f4a24c2469
("blk-mq: centralise related handling into blk_mq_get_driver_tag") which
removed 'data->hctx->tags->rqs[rq->tag] = rq' from blk_mq_rq_ctx_init()
which gets called:
blk_get_request
blk_mq_alloc_request
__blk_mq_alloc_request
blk_mq_rq_ctx_init
Since UFS task management requests are not dispatched by the block layer,
hctx->tags->rqs[rq->tag] remains NULL, and since blk_mq_tagset_busy_iter()
relies on finding requests using hctx->tags->rqs[rq->tag], UFS task
management requests are never found by blk_mq_tagset_busy_iter().
By using blk_mq_tagset_busy_iter(), the UFS driver was relying on internal
details of the block layer, which was fragile and subsequently got
broken. Fix by removing the use of blk_mq_tagset_busy_iter() and having the
driver keep track of task management requests.
Link: https://lore.kernel.org/r/20210922091059.4040-1-adrian.hunter@intel.com
Fixes: 1235fc569e0b ("scsi: ufs: core: Fix task management request completion timeout")
Fixes: 69a6c269c097 ("scsi: ufs: Use blk_{get,put}_request() to allocate and free TMFs")
Cc: stable@vger.kernel.org
Tested-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
[Adrian: Backport to v5.10]
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
drivers/scsi/ufs/ufshcd.c | 52 +++++++++++++++++----------------------
drivers/scsi/ufs/ufshcd.h | 1 +
2 files changed, 24 insertions(+), 29 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 930f35863cbb..5fd0a6ed181c 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6099,27 +6099,6 @@ static irqreturn_t ufshcd_check_errors(struct ufs_hba *hba)
return retval;
}
-struct ctm_info {
- struct ufs_hba *hba;
- unsigned long pending;
- unsigned int ncpl;
-};
-
-static bool ufshcd_compl_tm(struct request *req, void *priv, bool reserved)
-{
- struct ctm_info *const ci = priv;
- struct completion *c;
-
- WARN_ON_ONCE(reserved);
- if (test_bit(req->tag, &ci->pending))
- return true;
- ci->ncpl++;
- c = req->end_io_data;
- if (c)
- complete(c);
- return true;
-}
-
/**
* ufshcd_tmc_handler - handle task management function completion
* @hba: per adapter instance
@@ -6130,14 +6109,22 @@ static bool ufshcd_compl_tm(struct request *req, void *priv, bool reserved)
*/
static irqreturn_t ufshcd_tmc_handler(struct ufs_hba *hba)
{
- struct request_queue *q = hba->tmf_queue;
- struct ctm_info ci = {
- .hba = hba,
- .pending = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL),
- };
+ unsigned long pending, issued;
+ irqreturn_t ret = IRQ_NONE;
+ int tag;
+
+ pending = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL);
+
+ issued = hba->outstanding_tasks & ~pending;
+ for_each_set_bit(tag, &issued, hba->nutmrs) {
+ struct request *req = hba->tmf_rqs[tag];
+ struct completion *c = req->end_io_data;
+
+ complete(c);
+ ret = IRQ_HANDLED;
+ }
- blk_mq_tagset_busy_iter(q->tag_set, ufshcd_compl_tm, &ci);
- return ci.ncpl ? IRQ_HANDLED : IRQ_NONE;
+ return ret;
}
/**
@@ -6267,9 +6254,9 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
ufshcd_hold(hba, false);
spin_lock_irqsave(host->host_lock, flags);
- blk_mq_start_request(req);
task_tag = req->tag;
+ hba->tmf_rqs[req->tag] = req;
treq->req_header.dword_0 |= cpu_to_be32(task_tag);
memcpy(hba->utmrdl_base_addr + task_tag, treq, sizeof(*treq));
@@ -6313,6 +6300,7 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
}
spin_lock_irqsave(hba->host->host_lock, flags);
+ hba->tmf_rqs[req->tag] = NULL;
__clear_bit(task_tag, &hba->outstanding_tasks);
spin_unlock_irqrestore(hba->host->host_lock, flags);
@@ -9235,6 +9223,12 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
err = PTR_ERR(hba->tmf_queue);
goto free_tmf_tag_set;
}
+ hba->tmf_rqs = devm_kcalloc(hba->dev, hba->nutmrs,
+ sizeof(*hba->tmf_rqs), GFP_KERNEL);
+ if (!hba->tmf_rqs) {
+ err = -ENOMEM;
+ goto free_tmf_queue;
+ }
/* Reset the attached device */
ufshcd_vops_device_reset(hba);
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 1ba9c786feb6..35dd5197ccb9 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -734,6 +734,7 @@ struct ufs_hba {
struct blk_mq_tag_set tmf_tag_set;
struct request_queue *tmf_queue;
+ struct request **tmf_rqs;
struct uic_command *active_uic_cmd;
struct mutex uic_cmd_mutex;
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 5.10 2/2] scsi: ufs: core: Fix task management completion timeout race
2021-11-23 12:19 [PATCH 5.10 0/2] scsi: ufs: core: Fix task management completion Adrian Hunter
2021-11-23 12:19 ` [PATCH 5.10 1/2] " Adrian Hunter
@ 2021-11-23 12:19 ` Adrian Hunter
2021-11-23 12:30 ` [PATCH 5.10 0/2] scsi: ufs: core: Fix task management completion Greg KH
2 siblings, 0 replies; 4+ messages in thread
From: Adrian Hunter @ 2021-11-23 12:19 UTC (permalink / raw)
To: stable; +Cc: Martin K . Petersen, Bart Van Assche
commit 886fe2915cce6658b0fc19e64b82879325de61ea upstream.
__ufshcd_issue_tm_cmd() clears req->end_io_data after timing out, which
races with the completion function ufshcd_tmc_handler() which expects
req->end_io_data to have a value.
Note __ufshcd_issue_tm_cmd() and ufshcd_tmc_handler() are already
synchronized using hba->tmf_rqs and hba->outstanding_tasks under the
host_lock spinlock.
It is also not necessary (nor typical) to clear req->end_io_data because
the block layer does it before allocating out requests e.g. via
blk_get_request().
So fix by not clearing it.
Link: https://lore.kernel.org/r/20211108064815.569494-2-adrian.hunter@intel.com
Fixes: f5ef336fd2e4 ("scsi: ufs: core: Fix task management completion")
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
[Adrian: Backport to v5.10]
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
drivers/scsi/ufs/ufshcd.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 5fd0a6ed181c..e3a9a02cadf5 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6280,11 +6280,6 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
err = wait_for_completion_io_timeout(&wait,
msecs_to_jiffies(TM_CMD_TIMEOUT));
if (!err) {
- /*
- * Make sure that ufshcd_compl_tm() does not trigger a
- * use-after-free.
- */
- req->end_io_data = NULL;
ufshcd_add_tm_upiu_trace(hba, task_tag, "tm_complete_err");
dev_err(hba->dev, "%s: task management cmd 0x%.2x timed-out\n",
__func__, tm_function);
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread