diff options
| author | Dave Jiang <dave.jiang@intel.com> | 2021-12-08 10:01:27 -0700 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2021-12-13 11:10:41 +0530 |
| commit | 8affd8a4b5ce356c8900cfb037674f3a4a11fbdb (patch) | |
| tree | 84653da2e25d10966400b96bd205ec38f2dc1d50 /drivers/dma | |
| parent | 80936d68665be88dc3bf60884a71f2694eb6b1f1 (diff) | |
dmaengine: idxd: fix missed completion on abort path
Ming reported that with the abort path of the descriptor submission, there
can be a window where a completed descriptor can be missed to be completed
by the irq completion thread:
CPU A CPU B
Submit (successful)
Submit (fail)
irq_process_work_list() // empty
llist_abort_desc()
// remove all descs from pending list
irq_process_pending_llist() // empty
exit idxd_wq_thread() with no processing
Add opportunistic descriptor completion in the abort path in order to
remove the missed completion.
Fixes: 6b4b87f2c31a ("dmaengine: idxd: fix submission race window")
Reported-by: Ming Li <ming4.li@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/163898288714.443911.16084982766671976640.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/idxd/submit.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c index de76fb4abac2..83452fbbb168 100644 --- a/drivers/dma/idxd/submit.c +++ b/drivers/dma/idxd/submit.c @@ -106,6 +106,7 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie, { struct idxd_desc *d, *t, *found = NULL; struct llist_node *head; + LIST_HEAD(flist); desc->completion->status = IDXD_COMP_DESC_ABORT; /* @@ -120,7 +121,11 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie, found = desc; continue; } - list_add_tail(&desc->list, &ie->work_list); + + if (d->completion->status) + list_add_tail(&d->list, &flist); + else + list_add_tail(&d->list, &ie->work_list); } } @@ -130,6 +135,17 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie, if (found) complete_desc(found, IDXD_COMPLETE_ABORT); + + /* + * complete_desc() will return desc to allocator and the desc can be + * acquired by a different process and the desc->list can be modified. + * Delete desc from list so the list trasversing does not get corrupted + * by the other process. + */ + list_for_each_entry_safe(d, t, &flist, list) { + list_del_init(&d->list); + complete_desc(d, IDXD_COMPLETE_NORMAL); + } } int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc) |