Messages in this thread | | | From | Colin Ian King <> | Subject | re: dmaengine: idxd: fix submission race window | Date | Thu, 22 Jul 2021 19:56:53 +0100 |
| |
Hi,
Static analysis with Coverity on Linux-next has found an issue with the following commit:
commit 6b4b87f2c31ac1af4f244990a7cbfb50d3f3e33f Author: Dave Jiang <dave.jiang@intel.com> Date: Wed Jul 14 11:50:06 2021 -0700
dmaengine: idxd: fix submission race window
The analysis is as follows:
180static int irq_process_pending_llist(struct idxd_irq_entry *irq_entry, 181 int *processed, u64 data) 182{ 183 struct idxd_desc *desc, *t; 184 struct llist_node *head; 185 int queued = 0; 186 unsigned long flags; 187 188 *processed = 0; 189 head = llist_del_all(&irq_entry->pending_llist); 190 if (!head) 191 goto out; 192 193 llist_for_each_entry_safe(desc, t, head, llnode) {
assignment: Assigning: status = (*desc).completion->status & 0x7f.
194 u8 status = desc->completion->status & DSA_COMP_STATUS_MASK; 195
cond_between: Condition status, taking true branch. Now the value of status is between 1 and 127. cond_cannot_single: Condition status, taking true branch. Now the value of status cannot be equal to 0.
196 if (status) {
between: At condition status == IDXD_COMP_DESC_ABORT, the value of status must be between 1 and 127. cond_cannot_set: Condition status == IDXD_COMP_DESC_ABORT, taking false branch. Now the value of status cannot be equal to any of {0, 255}.
cannot_single: At condition status == IDXD_COMP_DESC_ABORT, the value of status cannot be equal to 0. dead_error_condition: The condition !!(status == IDXD_COMP_DESC_ABORT) cannot be true.
197 if (unlikely(status == IDXD_COMP_DESC_ABORT)) { Logically dead code (DEADCODE) dead_error_begin: Execution cannot reach this statement:
complete_desc(desc, IDXD_CO....
198 complete_desc(desc, IDXD_COMPLETE_ABORT); 199 (*processed)++; 200 continue; 201 } 202 203 complete_desc(desc, IDXD_COMPLETE_NORMAL); 204 (*processed)++;
The check (status == IDXD_COMP_DESC_ABORT) is always false since status was previously masked with 0x7f and IDXD_COMP_DESC_ABORT is 0xff
Colin.
| |