patch "libata: Add support for SCT Write Same" breaks system

Hi,

i tried recent linux-next on my laptop, and after boot system is almost unusable because most of apps just crash with segfaults and in dmesg output there are a lot of errors like this:

[   17.641510] do_general_protection: 51 callbacks suppressed
[   17.641514] traps: dpkg[2831] general protection ip:40be90 sp:7ffd6daad9b8 error:0 in dpkg[400000+43000]
[   17.648882] apport[2832]: segfault at 800000000 ip 0000000000485896 sp 00007ffece3b6c40 error 6 in python3.5[400000+3a7000]
[   17.648965] Process 2832(apport) has RLIMIT_CORE set to 1
[   17.648967] Aborting core
[   17.653463] gpu-manager[2818]: segfault at 0 ip 00007f77c4b8eb5a sp 00007ffc7a01b348 error 4 in libc-2.23.so[7f77c4af0000+1c0000]
[   17.660760] apport[2833]: segfault at 800000000 ip 0000000000485896 sp 00007ffddfe2a650 error 6 in python3.5[400000+3a7000]
[   17.660841] Process 2833(apport) has RLIMIT_CORE set to 1
[   17.660843] Aborting core
[   18.192604] apport[2847]: segfault at 800000000 ip 0000000000485896 sp 00007ffd2d4a82c0 error 6 in python3.5[400000+3a7000]
[   18.192630] Process 2847(apport) has RLIMIT_CORE set to 1
[   18.192633] Aborting core
[   19.089476] traps: dpkg[2861] general protection ip:40be90 sp:7ffcabc70fa8 error:0 in dpkg[400000+43000]
[   19.096747] apport[2862]: segfault at 800000000 ip 0000000000485896 sp 00007ffeda308490 error 6 in python3.5[400000+3a7000]
[   19.096827] Process 2862(apport) has RLIMIT_CORE set to 1
[   19.096829] Aborting core
[   19.101197] gpu-manager[2849]: segfault at 0 ip 00007fdccfef8b5a sp 00007ffeb4758488 error 4 in libc-2.23.so[7fdccfe5a000+1c0000]
[   19.106683] apport[2863]: segfault at 800000000 ip 0000000000485896 sp 00007ffcf8955d10 error 6 in python3.5[400000+3a7000]
[   19.106708] Process 2863(apport) has RLIMIT_CORE set to 1
[   19.106709] Aborting core
[   19.616176] apport[2898]: segfault at 800000000 ip 0000000000485896 sp 00007ffd12c29180 error 6 in python3.5[400000+3a7000]
[   19.616216] Process 2898(apport) has RLIMIT_CORE set to 1
[   19.616217] Aborting core
[   23.182904] lsb_release[2911]: segfault at 800000000 ip 0000000000485896 sp 00007ffca2f6bec0 error 6 in python3.5[400000+3a7000]
[   23.185672] apport[2913]: segfault at 800000000 ip 0000000000485896 sp 00007ffcf199e160 error 6 in python3.5[400000+3a7000]
[   23.185698] Process 2913(apport) has RLIMIT_CORE set to 1
[   23.185698] Aborting core
[   23.212363] apport[2921]: segfault at 800000000 ip 0000000000485896 sp 00007ffe934094c0 error 6 in python3.5[400000+3a7000]
[   23.212389] Process 2921(apport) has RLIMIT_CORE set to 1
[   23.212390] Aborting core
[   23.223112] apport[2926]: segfault at 800000000 ip 0000000000485896 sp 00007ffcc68e1240 error 6 in python3.5[400000+3a7000]
[   23.223137] Process 2926(apport) has RLIMIT_CORE set to 1
[   23.223137] Aborting core

git bisect points at commit 7b20309428598df00ffe ("libata: Add support for SCT Write Same". I temporary fixed problem with the following change:

index 08d9c8e..0dcd59e 100644
@@ -1159,6 +1159,7 @@ static void ata_scsi_sdev_config(struct scsi_device *sdev)
 {
        sdev->use_10_for_rw = 1;
        sdev->use_10_for_ms = 1;
+       sdev->no_write_same = 1;
 
        /* Schedule policy is determined by ->qc_defer() callback and
         * it needs to see every deferred qc.  Set dev_blocked to 1 to

Don't know whether it will help or not, but here is my hdparm output:

sudo hdparm -I /dev/sda

/dev/sda:

ATA device, with non-removable media

	Model Number:       SAMSUNG MZNLN512HCJH-000L1              
	Serial Number:      S201NX0H404301      
	Firmware Revision:  EMT22L0Q
	Transport:          Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6, SATA Rev 3.0
Standards:
	Used: unknown (minor revision code 0x0039) 
	Supported: 9 8 7 6 5 
	Likely used: 9

Configuration:
Logical max current
cylinders 16383 16383
heads 16 16
sectors/track 63 63
--
CHS current addressable sectors: 16514064
LBA user addressable sectors: 268435455
LBA48 user addressable sectors: 1000215216
Logical Sector size: 512 bytes
Physical Sector size: 512 bytes
Logical Sector-0 offset: 0 bytes
device size with M = 1024*1024: 488386 MBytes
device size with M = 1000*1000: 512110 MBytes (512 GB)
cache/buffer size = unknown
Nominal Media Rotation Rate: Solid State Device
Capabilities:
LBA, IORDY(can be disabled)
Queue depth: 32
Standby timer values: spec'd by Standard, no device specific minimum
R/W multiple sector transfer: Max = 16 Current = 16
DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6
Cycle time: min=120ns recommended=120ns
PIO: pio0 pio1 pio2 pio3 pio4
Cycle time: no flow control=120ns IORDY flow control=120ns
Commands/features:
Enabled Supported:
* SMART feature set
Security Mode feature set
* Power Management feature set
* Write cache
* Look-ahead
* Host Protected Area feature set
* WRITE_BUFFER command
* READ_BUFFER command
* NOP cmd
* DOWNLOAD_MICROCODE
SET_MAX security extension
* 48-bit Address feature set
* Device Configuration Overlay feature set
* Mandatory FLUSH_CACHE
* FLUSH_CACHE_EXT
* SMART error logging
* SMART self-test
* General Purpose Logging feature set
* WRITE_{DMA|MULTIPLE}_FUA_EXT
* 64-bit World wide name
Write-Read-Verify feature set
* WRITE_UNCORRECTABLE_EXT command
* {READ,WRITE}_DMA_EXT_GPL commands
* Segmented DOWNLOAD_MICROCODE
* Gen1 signaling speed (1.5Gb/s)
* Gen2 signaling speed (3.0Gb/s)
* Gen3 signaling speed (6.0Gb/s)
* Native Command Queueing (NCQ)
* Phy event counters
* READ_LOG_DMA_EXT equivalent to READ_LOG_EXT
* DMA Setup Auto-Activate optimization
Device-initiated interface power management
* Asynchronous notification (eg. media change)
* Software settings preservation
Device Sleep (DEVSLP)
* SMART Command Transport (SCT) feature set
* SCT Write Same (AC2)
* SCT Error Recovery Control (AC3)
* SCT Features Control (AC4)
* SCT Data Tables (AC5)
* DOWNLOAD MICROCODE DMA command
* SET MAX SETPASSWORD/UNLOCK DMA commands
* WRITE BUFFER DMA command
* READ BUFFER DMA command
* Data Set Management TRIM supported (limit 8 blocks)
Security:
Master password revision code = 65534
supported
not enabled
not locked
frozen
not expired: security count
supported: enhanced erase
2min for SECURITY ERASE UNIT. 8min for ENHANCED SECURITY ERASE UNIT.
Logical Unit WWN Device Identifier: 5002538d00000000

	NAA		: 5
	IEEE OUI	: 002538
	Unique ID	: d00000000

Device Sleep:
DEVSLP Exit Timeout (DETO): 50 ms (drive) Minimum DEVSLP Assertion Time (MDAT): 30 ms (drive)
Checksum: correct

Hello,

...

Shaun, any ideas? If this isn't an easy fix, I'm gonna disable write_same for all devices for now.

Thanks.

tejun

Hello, Shaun.

I'd much prefer enabling this only on ZBC devices. There isn't any real benefits to !ZBC devices, right? Using non-essential features on ATA never goes well.

Thanks.

tejun

Sure I'm fine with that.

I'll move the WRITE SAME support to be conditional on ZBC. Sending a patch as soon as it's tested.

Thanks
--
Shaun

Restrict support SCT Write Same to devices which also support ZAC where support is required.

---
 drivers/ata/libata-scsi.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

index 2f5487f..9cceb4a 100644
@@ -3562,9 +3562,9 @@ static unsigned int ata_scsiop_maint_in(struct ata_scsi_args *args, u8 *rbuf)
 		supported = 3;
 		break;
 	case WRITE_SAME_16:
-		if (ata_id_sct_write_same(dev->id))
-			supported = 3;
-		break;
+		if (!ata_id_sct_write_same(dev->id))
+			break;
+		/* fallthrough: if SCT ... only enable for ZBC */
 	case ZBC_IN:
 	case ZBC_OUT:
 		if (ata_id_zoned_cap(dev->id) ||

2.9.3

Works for me too, thank you.

Applied to libata/for-4.9.

Thanks.

tejun

I've posted a patch for !ZBC.

Mike, can you confirm if this works for you?

Thanks!

(Apologies for the html reply earlier)

Shaun Tancheff