--- /dev/null
+From 886fe2915cce6658b0fc19e64b82879325de61ea Mon Sep 17 00:00:00 2001
+From: Adrian Hunter <adrian.hunter@intel.com>
+Date: Mon, 8 Nov 2021 08:48:14 +0200
+Subject: scsi: ufs: core: Fix task management completion timeout race
+
+From: Adrian Hunter <adrian.hunter@intel.com>
+
+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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/scsi/ufs/ufshcd.c | 5 -----
+ 1 file changed, 5 deletions(-)
+
+--- a/drivers/scsi/ufs/ufshcd.c
++++ b/drivers/scsi/ufs/ufshcd.c
+@@ -6280,11 +6280,6 @@ static int __ufshcd_issue_tm_cmd(struct
+ 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);
--- /dev/null
+From f5ef336fd2e4c36dedae4e7ca66cf5349d6fda62 Mon Sep 17 00:00:00 2001
+From: Adrian Hunter <adrian.hunter@intel.com>
+Date: Wed, 22 Sep 2021 12:10:59 +0300
+Subject: scsi: ufs: core: Fix task management completion
+
+From: Adrian Hunter <adrian.hunter@intel.com>
+
+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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/scsi/ufs/ufshcd.c | 52 ++++++++++++++++++++--------------------------
+ drivers/scsi/ufs/ufshcd.h | 1
+ 2 files changed, 24 insertions(+), 29 deletions(-)
+
+--- a/drivers/scsi/ufs/ufshcd.c
++++ b/drivers/scsi/ufs/ufshcd.c
+@@ -6099,27 +6099,6 @@ static irqreturn_t ufshcd_check_errors(s
+ 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 reque
+ */
+ 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;
+
+- blk_mq_tagset_busy_iter(q->tag_set, ufshcd_compl_tm, &ci);
+- return ci.ncpl ? IRQ_HANDLED : IRQ_NONE;
++ complete(c);
++ ret = IRQ_HANDLED;
++ }
++
++ return ret;
+ }
+
+ /**
+@@ -6267,9 +6254,9 @@ static int __ufshcd_issue_tm_cmd(struct
+ 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
+ }
+
+ 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, voi
+ 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);
+--- 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;
projects / thirdparty / kernel / stable-queue.git / commitdiff
