[PATCH] scsi: message: fusion: Fix a possible data race in mpt_ioc_reset()

Tuo Li
2023-07-15T02:53:42Z

The variable ioc->taskmgmt_quiesce_io is often protected by the lock
ioc->taskmgmt_lock when is accessed. Here is an example in
mpt_SoftResetHandler():

spin_lock_irqsave(&ioc->taskmgmt_lock, flags);
...
ioc->taskmgmt_quiesce_io = 0;
...
spin_unlock_irqrestore(&ioc->taskmgmt_lock, flags);

However, ioc->taskmgmt_quiesce_io is set to 1 without holding the lock
ioc->taskmgmt_lock in mpt_ioc_reset():

case MPT_IOC_SETUP_RESET:
ioc->taskmgmt_quiesce_io = 1;

In my opinion, this may be a harmful race, because the value of
ioc->taskmgmt_quiesce_io can be rewritten by mpt_ioc_reset() when another
thread is accessing it.

To fix this possible data race, a lock and unlock pair is added when
accessing the variable ioc->taskmgmt_quiesce_io.

Reported-by: BassCheck <bass@buaa.edu.cn>
Signed-off-by: Tuo Li <islituo@gmail.com>
---
drivers/message/fusion/mptbase.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/message/fusion/mptbase.c b/drivers/message/fusion/mptbase.c
index 4bf669c55649..560057daf4ee 100644
--- a/drivers/message/fusion/mptbase.c
+++ b/drivers/message/fusion/mptbase.c
@@ -6561,9 +6561,13 @@ mpt_config(MPT_ADAPTER *ioc, CONFIGPARMS *pCfg)
static int
mpt_ioc_reset(MPT_ADAPTER *ioc, int reset_phase)
{
+ unsigned long flags;
+
switch (reset_phase) {
case MPT_IOC_SETUP_RESET:
+ spin_lock_irqsave(&ioc->taskmgmt_lock, flags);
ioc->taskmgmt_quiesce_io = 1;
+ spin_unlock_irqrestore(&ioc->taskmgmt_lock, flags);
dtmprintk(ioc, printk(MYIOC_s_DEBUG_FMT
"%s: MPT_IOC_SETUP_RESET\n", ioc->name, __func__));
break;
--
2.34.1