3.16.57-rc1 review patch. If anyone has any objections, please let me know.
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From: Shaohua Li shli@fb.com
commit 5067c0469c643512f24786990e315f9c15cc7d24 upstream.
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@cybernetics.com Signed-off-by: Shaohua Li shli@fb.com Signed-off-by: Tejun Heo tj@kernel.org [bwh: Backported to 3.16: Drop changes to ata_qc_{new_init,free}(); we don't actually have the tag allocation bug] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- 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(-)
--- a/drivers/scsi/ipr.c +++ b/drivers/scsi/ipr.c @@ -6862,7 +6862,8 @@ static struct ata_port_operations ipr_sa };
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, --- a/drivers/scsi/libsas/sas_ata.c +++ b/drivers/scsi/libsas/sas_ata.c @@ -566,7 +566,8 @@ static struct ata_port_operations sas_sa };
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, --- 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 */