Samsung Finds, Fixes Bug In Linux Trim Code

New submitter Mokki writes: After many complaints that Samsung SSDs corrupted data when used with Linux, Samsung found out that the bug was in the Linux kernel and submitted a patch to fix it. It turns out that kernels without the final fix can corrupt data if the system is using linux md raid with raid0 or raid10 and issues trim/discard commands (either fstrim or by the filesystem itself). The vendor of the drive did not matter and the previous blacklisting of Samsung drives for broken queued trim support can be most likely lifted after further tests. According to this post the bug has been around for a long time.

Comments

Crying wolf

[Sponge Bath]

When Apple updated OS X to allow TRIM on non-Apple supplied SSDs, forums were flooded with people claiming you should never use Samsung because they were fundamentally broken with regards to TRIM. Their "proof" was that corruption happened on Linux and they would not be swayed by the thought that maybe the problem was with Linux.

Re:Crying wolf

[kaiser423]

What makes you think that? Samsung is one signature away (PIA -- Proprietary Information Agreement) from viewing the vendor's source code and advising them. It's pretty damn routine and uncontroversial. I don't understand why people think that just because something is not open source that no one outside of the company ever, ever, under any circumstances can see a hunk of the code. Just sign a PIA and over the code in a secure manner, or give them remote VPN access to the test box. Pretty damn simple and routine.

Re:Why did it only happened on Samsung's SSDs?

[Anonymous Coward]

Confirmation bias. It was happening with other brands, but for one reason or another, people focused in on Samsung as the culprit, and once that happened, there was no getting out of it.

Re:Bravo

[DarkOx]

Sure there was self interest. Still I think they deserve a lot of credit here. Rather than the typical "Its not my code" response from a developer who is sure the problem is elsewhere (rightly or wrongly) they actually found and fixed the problem. That is good behavior!

Re: Bravo

[bill_mcgonigle]

I take some of that back. It seems the real credit for digging in goes to these guys. Samsung came in a month ago after they were provided a test suite and then gets credit for finding the kernel code path that caused the problem. An Oracle engineer provided a more-correct patch.

Re:awkward!

[Anonymous Coward]

The firmware bug of Samsung drives, a very severe one actually, was confirmed by Samsung. The RAID 0 issue is a totally different one, hardly affecting anyone.

So yes, the severe issue was a bug on Samsung side, thile the very rare RAID 0 bug is Linux kernel one.

Re:awkward!

[GigaplexNZ]

I've read the articles. There are two separate bugs here. One, Samsung drives advertise support for queued TRIM even though it's not properly supported, causing corruption. Two, the kernel had a TRIM bug that affected serial TRIM with mdadm RAID, which is the kernel bug Samsung found and fixed. The queued TRIM bug still exists in the Samsung firmware.

Re:fairly common to blacklist devices

[Anonymous Coward]

Sorry, that's incorrect.

There's a bug on MD raid0 and raid10. In Linux.

There is a data destroyer bug in SAMSUNG NCQ TRIM firmware. Which is *blacklisted*, so that it uses the non-ncq trim.

See? You're an idiot and everyone but you actually knew what they were complaining about. The samsung firmware is buggy crap that destroys data on NCQ TRIM, and the Linux kernel had a data destroyer bug in RAID0/RAID10 + TRIM that was fixed by a samsung engineer.

The samsung firmware is still broken, the linux kernel has been fixed, and you're still an useless idiot.