| Message ID | 20240527061920.48626-1-lirongqing@baidu.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [RFC] dmaengine: idxd: Fix possible Use-After-Free in irq_process_work_list | expand |
> I think when the description is freed, it maybe used again because of race, then > it's next maybe pointer a value that should not be freed > > To prevent this, list_for_each_entry_safe should be used. > Rewrite the commit header: dmaengine: idxd: Fix possible Use-After-Free in irq_process_work_list The description has been freed in idxd_desc_complete(), should not be used in iteration, so replace list_for_each_entry with list_for_each_entry_safe to prevent the accessing Signed-off-by: Li RongQing <lirongqing@baidu.com> > Signed-off-by: Li RongQing <lirongqing@baidu.com> > --- > drivers/dma/idxd/irq.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c index > 8dc029c..0c7fed7 100644 > --- a/drivers/dma/idxd/irq.c > +++ b/drivers/dma/idxd/irq.c > @@ -611,7 +611,7 @@ static void irq_process_work_list(struct idxd_irq_entry > *irq_entry) > > spin_unlock(&irq_entry->list_lock); > > - list_for_each_entry(desc, &flist, list) { > + list_for_each_entry_safe(desc, n, &flist, list) { > /* > * Check against the original status as ABORT is software defined > * and 0xff, which DSA_COMP_STATUS_MASK can mask out. > -- > 2.9.4
On 5/26/24 11:19 PM, Li RongQing wrote: > I think when the description is freed, it maybe used again because of s/description/descriptor/ > race, then it's next maybe pointer a value that should not be freed > > To prevent this, list_for_each_entry_safe should be used. > > Signed-off-by: Li RongQing <lirongqing@baidu.com> > --- > drivers/dma/idxd/irq.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c > index 8dc029c..0c7fed7 100644 > --- a/drivers/dma/idxd/irq.c > +++ b/drivers/dma/idxd/irq.c > @@ -611,7 +611,7 @@ static void irq_process_work_list(struct idxd_irq_entry *irq_entry) > > spin_unlock(&irq_entry->list_lock); > > - list_for_each_entry(desc, &flist, list) { > + list_for_each_entry_safe(desc, n, &flist, list) { > /* > * Check against the original status as ABORT is software defined > * and 0xff, which DSA_COMP_STATUS_MASK can mask out. I see what you are pointing at. I think you will also need a list_del(&desc->list); immediately after the comments. Because if the descriptor is freed and given out to a different thread while the code is still walking the list, the iterator may hit a bad pointer due to the freed descriptor pointing to something else. Also, please include a Fixes tag for the fix. Thanks!
> Because if the descriptor is freed and given out to a different thread while the > code is still walking the list, the iterator may hit a bad pointer due to the freed > descriptor pointing to something else. > > Also, please include a Fixes tag for the fix. Thanks! Ok, I will send V2, thanks Br
diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c index 8dc029c..0c7fed7 100644 --- a/drivers/dma/idxd/irq.c +++ b/drivers/dma/idxd/irq.c @@ -611,7 +611,7 @@ static void irq_process_work_list(struct idxd_irq_entry *irq_entry) spin_unlock(&irq_entry->list_lock); - list_for_each_entry(desc, &flist, list) { + list_for_each_entry_safe(desc, n, &flist, list) { /* * Check against the original status as ABORT is software defined * and 0xff, which DSA_COMP_STATUS_MASK can mask out.
I think when the description is freed, it maybe used again because of race, then it's next maybe pointer a value that should not be freed To prevent this, list_for_each_entry_safe should be used. Signed-off-by: Li RongQing <lirongqing@baidu.com> --- drivers/dma/idxd/irq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)