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scsi: qla2xxx: Fix soft lockup polling continuation IOCB signature

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qla27xx_copy_multiple_pkt() and qla27xx_copy_fpin_pkt() poll
rsp_q->ring_ptr->signature for RESPONSE_PROCESSED (0xDEADDEAD) to decide
whether the next continuation IOCB has arrived, spinning on cpu_relax()
without advancing the ring or decrementing the entry count while it has
not. response_t::signature lives at byte offset 60, but a continuation
IOCB (sts_cont_entry_t / struct sts_cont_entry_ext) carries raw FC frame
payload at that offset (data[56..59]). A received frame whose payload
bytes happen to equal 0xDEADDEAD is therefore misread as "not yet
arrived", and the loop spins forever in interrupt/DPC context, causing a
CPU soft lockup.

The poll is also unnecessary: callers of qla27xx_copy_multiple_pkt()
(PT_LS4_UNSOL and the NVMe purls path) already gate on
qla_chk_cont_iocb_avail(), which guarantees all entry_count IOCBs are
present before copying begins. The sibling helper
__qla_copy_purex_to_buffer() already drops the signature poll and relies
on the entry_type == STATUS_CONT_TYPE guard instead.

Remove the signature busy-wait from both helpers, keeping the entry_type
guard, and gate the FPIN path with qla_chk_cont_iocb_avail() so it defers
and re-processes on the next interrupt once all continuation IOCBs have
arrived, mirroring the ELS_AUTH_ELS and PT_LS4_UNSOL arms. With this the
signature field is never read on a continuation IOCB, eliminating the
payload-aliasing lockup.

Fixes: 9f2475fe74 ("scsi: qla2xxx: SAN congestion management implementation")
Cc: stable@vger.kernel.org
Reported-by: Sashiko <sashiko-dev@google.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Link: https://patch.msgid.link/20260730155838.2119230-15-njavali@marvell.com
Signed-off-by: Martin K. Petersen (Oracle) <mkp@kernel.org>
This commit is contained in:
Nilesh Javali
2026-07-30 21:28:19 +05:30
committed by Martin K. Petersen (Oracle)
parent 3ba019bdd8
commit d7e3fa7d06
1 changed files with 16 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
drivers/scsi/qla2xxx/qla_isr.c
View File

@@ -1002,14 +1002,6 @@ qla27xx_copy_multiple_pkt(struct scsi_qla_host *vha, void **pkt,
do {
while ((total_bytes > 0) && (entry_count_remaining > 0)) {
if (rsp_q->ring_ptr->signature == RESPONSE_PROCESSED) {
ql_dbg(ql_dbg_async, vha, 0x5084,
"Ran out of IOCBs, partial data 0x%x\n",
buffer_copy_offset);
cpu_relax();
continue;
}
*pkt = rsp_q->ring_ptr;
data = ((sts_cont_entry_t *)*pkt)->data;
data_sz = qla_sts_cont_data_size(ha);
@@ -1299,14 +1291,6 @@ qla27xx_copy_fpin_pkt(struct scsi_qla_host *vha, void **pkt,
do {
while ((total_bytes > 0) && (entry_count_remaining > 0)) {
if (rsp_q->ring_ptr->signature == RESPONSE_PROCESSED) {
ql_dbg(ql_dbg_async, vha, 0x5084,
"Ran out of IOCBs, partial data 0x%x\n",
buffer_copy_offset);
cpu_relax();
continue;
}
*pkt = rsp_q->ring_ptr;
data = ((sts_cont_entry_t *)*pkt)->data;
data_sz = qla_sts_cont_data_size(ha);
@@ -4272,9 +4256,24 @@ void qla24xx_process_response_queue(struct scsi_qla_host *vha,
"SCM not active for this port\n");
break;
}
if (qla_chk_cont_iocb_avail(vha, rsp,
(response_t *)pkt, rsp_in)) {
/*
* ring_ptr and ring_index were
* pre-incremented above. Reset them
* back to current. Wait for next
* interrupt with all IOCBs to arrive
* and re-process.
*/
qla_rsp_ring_rewind_to(rsp,
(response_t *)pkt, cur_ring_index);
ql_dbg(ql_dbg_init, vha, 0x5095,
"Defer processing FPIN...\n");
return;
}
pure_item = qla27xx_copy_fpin_pkt(vha,
(void **)&pkt, &rsp);
__update_rsp_in(is_shadow_hba, rsp, rsp_in);
if (!pure_item)
break;
qla24xx_queue_purex_item(vha, pure_item,