Messages in this thread Patch in this message | | | From | Tuo Li <> | Subject | [PATCH v2] scsi: message: fusion: Fix a possible data race in mpt_ioc_reset() | Date | Mon, 30 Oct 2023 17:09:24 +0800 |
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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(), which can cause possible data races:
case MPT_IOC_SETUP_RESET: ioc->taskmgmt_quiesce_io = 1;
To fix this possible data race, WRITE_ONCE() is used to access the variable ioc->taskmgmt_lock.
Reported-by: BassCheck <bass@buaa.edu.cn> Signed-off-by: Tuo Li <islituo@gmail.com> --- v2: * Replace lock operations with a WRITE_ONCE to avoid possible data races. Thank Bart Van Assche for helpful advice. --- drivers/message/fusion/mptbase.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/message/fusion/mptbase.c b/drivers/message/fusion/mptbase.c index 4bf669c55649..6c67eec9ab85 100644 --- a/drivers/message/fusion/mptbase.c +++ b/drivers/message/fusion/mptbase.c @@ -6563,7 +6563,7 @@ mpt_ioc_reset(MPT_ADAPTER *ioc, int reset_phase) { switch (reset_phase) { case MPT_IOC_SETUP_RESET: - ioc->taskmgmt_quiesce_io = 1; + WRITE_ONCE(ioc->taskmgmt_quiesce_io, 1); dtmprintk(ioc, printk(MYIOC_s_DEBUG_FMT "%s: MPT_IOC_SETUP_RESET\n", ioc->name, __func__)); break; -- 2.34.1
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