[Scst-devel] [PATCH v3 01/16] Revert "scsi: qla2xxx: Perform lockless command completion in abort path"

[Tony B. <to...@cy...>]

This reverts commit 0367076b0817d5c75dfb83001ce7ce5c64d803a9.

The commit being reverted added code to __qla2x00_abort_all_cmds() to
call sp->done() without holding a spinlock.  But unlike the older code
below it, this new code failed to check sp->cmd_type and just assumed
TYPE_SRB, which results in a jump to an invalid pointer in target-mode
with TYPE_TGT_CMD:

qla2xxx [0000:65:00.0]-d034:8: qla24xx_do_nack_work create sess success
  0000000009f7a79b
qla2xxx [0000:65:00.0]-5003:8: ISP System Error - mbx1=1ff5h mbx2=10h
  mbx3=0h mbx4=0h mbx5=191h mbx6=0h mbx7=0h.
qla2xxx [0000:65:00.0]-d01e:8: -> fwdump no buffer
qla2xxx [0000:65:00.0]-f03a:8: qla_target(0): System error async event
  0x8002 occurred
qla2xxx [0000:65:00.0]-00af:8: Performing ISP error recovery -
  ha=0000000058183fda.
BUG: kernel NULL pointer dereference, address: 0000000000000000
PF: supervisor instruction fetch in kernel mode
PF: error_code(0x0010) - not-present page
PGD 0 P4D 0
Oops: 0010 [#1] SMP
CPU: 2 PID: 9446 Comm: qla2xxx_8_dpc Tainted: G           O       6.1.133 #1
Hardware name: Supermicro Super Server/X11SPL-F, BIOS 4.2 12/15/2023
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc90001f93dc8 EFLAGS: 00010206
RAX: 0000000000000282 RBX: 0000000000000355 RCX: ffff88810d16a000
RDX: ffff88810dbadaa8 RSI: 0000000000080000 RDI: ffff888169dc38c0
RBP: ffff888169dc38c0 R08: 0000000000000001 R09: 0000000000000045
R10: ffffffffa034bdf0 R11: 0000000000000000 R12: ffff88810800bb40
R13: 0000000000001aa8 R14: ffff888100136610 R15: ffff8881070f7400
FS:  0000000000000000(0000) GS:ffff88bf80080000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 000000010c8ff006 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ? __die+0x4d/0x8b
 ? page_fault_oops+0x91/0x180
 ? trace_buffer_unlock_commit_regs+0x38/0x1a0
 ? exc_page_fault+0x391/0x5e0
 ? asm_exc_page_fault+0x22/0x30
 __qla2x00_abort_all_cmds+0xcb/0x3e0 [qla2xxx_scst]
 qla2x00_abort_all_cmds+0x50/0x70 [qla2xxx_scst]
 qla2x00_abort_isp_cleanup+0x3b7/0x4b0 [qla2xxx_scst]
 qla2x00_abort_isp+0xfd/0x860 [qla2xxx_scst]
 qla2x00_do_dpc+0x581/0xa40 [qla2xxx_scst]
 kthread+0xa8/0xd0
 </TASK>

Then commit 4475afa2646d ("scsi: qla2xxx: Complete command early within
lock") added the spinlock back, because not having the lock caused a
race and a crash.  But qla2x00_abort_srb() in the switch below already
checks for qla2x00_chip_is_down() and handles it the same way, so the
code above the switch is now redundant and still buggy in target-mode.
Remove it.

Cc: st...@vg...
Signed-off-by: Tony Battersby <to...@cy...>
---

v2 -> v3: no changes

v1 -> v2: no changes

 drivers/scsi/qla2xxx/qla_os.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index d4b484c0fd9d..a52293972e10 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -1862,12 +1862,6 @@ __qla2x00_abort_all_cmds(struct qla_qpair *qp, int res)
 	for (cnt = 1; cnt < req->num_outstanding_cmds; cnt++) {
 		sp = req->outstanding_cmds[cnt];
 		if (sp) {
-			if (qla2x00_chip_is_down(vha)) {
-				req->outstanding_cmds[cnt] = NULL;
-				sp->done(sp, res);
-				continue;
-			}
-
 			switch (sp->cmd_type) {
 			case TYPE_SRB:
 				qla2x00_abort_srb(qp, sp, res, &flags);
-- 
2.43.0