lkml.org 
[lkml]   [2023]   [Oct]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/1] core: ufs: fix racing issue between force complete and isr
Date
From: Alice Chao <alice.chao@mediatek.com>

While error handler force complete command (Thread A) and completion irq
raising (Thread B) of the same command, it may cause race condition.

Below is racing step (from 1 to 6):
ufshcd_mcq_compl_pending_transfer (Thread A)
1 if (cmd && !test_bit(SCMD_STATE_COMPLETE, &cmd->state)) {
5 spin_lock_irqsave(&hwq->cq_lock, flags); // wait lock release
set_host_byte(cmd, DID_REQUEUE);
6 ufshcd_release_scsi_cmd(hba, lrbp); // access null pointer
scsi_done(cmd);
spin_unlock_irqrestore(&hwq->cq_lock, flags);
}

ufshcd_mcq_poll_cqe_lock (Thread B)
2 spin_lock_irqsave(&hwq->cq_lock, flags);
ufshcd_mcq_poll_cqe_nolock()
ufshcd_compl_one_cqe()
3 ufshcd_release_scsi_cmd() // lrbp->cmd = NULL;
4 spin_unlock_irqrestore(&hwq->cq_lock, flags);

Signed-off-by: Alice Chao <alice.chao@mediatek.com>
---
drivers/ufs/core/ufshcd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 8382e8cfa414..ef6bd146a767 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -5518,13 +5518,13 @@ static void ufshcd_mcq_compl_pending_transfer(struct ufs_hba *hba,
* For those cmds of which the cqes are not present
* in the cq, complete them explicitly.
*/
+ spin_lock_irqsave(&hwq->cq_lock, flags);
if (cmd && !test_bit(SCMD_STATE_COMPLETE, &cmd->state)) {
- spin_lock_irqsave(&hwq->cq_lock, flags);
set_host_byte(cmd, DID_REQUEUE);
ufshcd_release_scsi_cmd(hba, lrbp);
scsi_done(cmd);
- spin_unlock_irqrestore(&hwq->cq_lock, flags);
}
+ spin_unlock_irqrestore(&hwq->cq_lock, flags);
} else {
ufshcd_mcq_poll_cqe_lock(hba, hwq);
}
--
2.18.0
\
 
 \ /
  Last update: 2023-10-24 10:44    [W:0.057 / U:0.768 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site