>From 5067c0469c643512f24786990e315f9c15cc7d24 Mon Sep 17 00:00:00 2001
From: Shaohua Li <shli@xxxxxx>
Date: Thu, 12 Mar 2015 10:32:18 -0700
SAS controller has its own tag allocation, which doesn't directly match to ATA
tag, so SAS and SATA have different code path for ata tags. Originally we use
port->scsi_host (98bd4be1) to destinguish SAS controller, but libsas set
->scsi_host too, so we can't use it for the destinguish, we add a new flag for
this purpose.
Without this patch, the following oops can happen because scsi-mq uses
a host-wide tag map shared among all devices with some integer tag
values >= ATA_MAX_QUEUE. These unexpectedly high tag values cause
__ata_qc_from_tag() to return NULL, which is then dereferenced in
ata_qc_new_init().
BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
IP: [<ffffffff804fd46e>] ata_qc_new_init+0x3e/0x120
PGD 32adf0067 PUD 32adf1067 PMD 0
Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
Modules linked in: iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi igb
i2c_algo_bit ptp pps_core pm80xx libsas scsi_transport_sas sg coretemp
eeprom w83795 i2c_i801
CPU: 4 PID: 1450 Comm: cydiskbench Not tainted 4.0.0-rc3 #1
Hardware name: Supermicro X8DTH-i/6/iF/6F/X8DTH, BIOS 2.1b 05/04/12
task: ffff8800ba86d500 ti: ffff88032a064000 task.ti: ffff88032a064000
RIP: 0010:[<ffffffff804fd46e>] [<ffffffff804fd46e>] ata_qc_new_init+0x3e/0x120
RSP: 0018:ffff88032a067858 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff8800ba0d2230 RCX: 000000000000002a
RDX: ffffffff80505ae0 RSI: 0000000000000020 RDI: ffff8800ba0d2230
RBP: ffff88032a067868 R08: 0000000000000201 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800ba0d0000
R13: ffff8800ba0d2230 R14: ffffffff80505ae0 R15: ffff8800ba0d0000
FS: 0000000041223950(0063) GS:ffff88033e480000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000058 CR3: 000000032a0a3000 CR4: 00000000000006e0
Stack:
ffff880329eee758 ffff880329eee758 ffff88032a0678a8 ffffffff80502dad
ffff8800ba167978 ffff880329eee758 ffff88032bf9c520 ffff8800ba167978
ffff88032bf9c520 ffff88032bf9a290 ffff88032a0678b8 ffffffff80506909
Call Trace:
[<ffffffff80502dad>] ata_scsi_translate+0x3d/0x1b0
[<ffffffff80506909>] ata_sas_queuecmd+0x149/0x2a0
[<ffffffffa0046650>] sas_queuecommand+0xa0/0x1f0 [libsas]
[<ffffffff804ea544>] scsi_dispatch_cmd+0xd4/0x1a0
[<ffffffff804eb50f>] scsi_queue_rq+0x66f/0x7f0
[<ffffffff803e5098>] __blk_mq_run_hw_queue+0x208/0x3f0
[<ffffffff803e54b8>] blk_mq_run_hw_queue+0x88/0xc0
[<ffffffff803e5c74>] blk_mq_insert_request+0xc4/0x130
[<ffffffff803e0b63>] blk_execute_rq_nowait+0x73/0x160
[<ffffffffa0023fca>] sg_common_write+0x3da/0x720 [sg]
[<ffffffffa0025100>] sg_new_write+0x250/0x360 [sg]
[<ffffffffa0025feb>] sg_write+0x13b/0x450 [sg]
[<ffffffff8032ec91>] vfs_write+0xd1/0x1b0
[<ffffffff8032ee54>] SyS_write+0x54/0xc0
[<ffffffff80689932>] system_call_fastpath+0x12/0x17
tj: updated description.
Fixes: 12cb5ce101ab ("libata: use blk taging")
Reported-and-tested-by: Tony Battersby <tonyb@xxxxxxxxxxxxxxx>
Signed-off-by: Shaohua Li <shli@xxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
Applied with description updated.
Thanks.
drivers/ata/libata-core.c | 4 ++--
drivers/scsi/ipr.c | 3 ++-
drivers/scsi/libsas/sas_ata.c | 3 ++-
include/linux/libata.h | 1 +
4 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 4c35f08..ef150eb 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4737,7 +4737,7 @@ struct ata_queued_cmd *ata_qc_new_init(struct ata_device *dev, int tag)
return NULL;
/* libsas case */
- if (!ap->scsi_host) {
+ if (ap->flags & ATA_FLAG_SAS_HOST) {
tag = ata_sas_allocate_tag(ap);
if (tag < 0)
return NULL;
@@ -4776,7 +4776,7 @@ void ata_qc_free(struct ata_queued_cmd *qc)
tag = qc->tag;
if (likely(ata_tag_valid(tag))) {
qc->tag = ATA_TAG_POISON;
- if (!ap->scsi_host)
+ if (ap->flags & ATA_FLAG_SAS_HOST)
ata_sas_free_tag(tag, ap);
}
}
diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index 9219953..d9afc51 100644
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -6815,7 +6815,8 @@ static struct ata_port_operations ipr_sata_ops = {
};
static struct ata_port_info sata_port_info = {
- .flags = ATA_FLAG_SATA | ATA_FLAG_PIO_DMA,
+ .flags = ATA_FLAG_SATA | ATA_FLAG_PIO_DMA |
+ ATA_FLAG_SAS_HOST,
.pio_mask = ATA_PIO4_ONLY,
.mwdma_mask = ATA_MWDMA2,
.udma_mask = ATA_UDMA6,
diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index 932d9cc..9c706d8 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -547,7 +547,8 @@ static struct ata_port_operations sas_sata_ops = {
};
static struct ata_port_info sata_port_info = {
- .flags = ATA_FLAG_SATA | ATA_FLAG_PIO_DMA | ATA_FLAG_NCQ,
+ .flags = ATA_FLAG_SATA | ATA_FLAG_PIO_DMA | ATA_FLAG_NCQ |
+ ATA_FLAG_SAS_HOST,
.pio_mask = ATA_PIO4,
.mwdma_mask = ATA_MWDMA2,
.udma_mask = ATA_UDMA6,
diff --git a/include/linux/libata.h b/include/linux/libata.h
index fc03efa..6b08cc1 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -232,6 +232,7 @@ enum {
* led */
ATA_FLAG_NO_DIPM = (1 << 23), /* host not happy with DIPM */
ATA_FLAG_LOWTAG = (1 << 24), /* host wants lowest available tag */
+ ATA_FLAG_SAS_HOST = (1 << 25), /* SAS host */
/* bits 24:31 of ap->flags are reserved for LLD specific flags */
--
2.1.0
--
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