Stories
Slash Boxes
Comments

SoylentNews is people

SoylentNews is powered by your submissions, so send in your scoop. Only 9 submissions in the queue.
posted by martyb on Friday June 05 2020, @08:40AM   Printer-friendly
from the help-less,-please dept.

Linus Torvalds rejects 'beyond stupid' AWS-made Linux patch for Intel CPU Snoop attack

Linux kernel head Linus Torvalds has trashed a patch from Amazon Web Services (AWS) engineers that was aimed at mitigating the Snoop attack on Intel CPUs discovered by an AWS engineer earlier this year. [...] AWS engineer Pawel Wieczorkiewicz discovered a way to leak data from an Intel CPU's memory via its L1D cache, which sits in CPU cores, through 'bus snooping' – the cache updating operation that happens when data is modified in L1D.

In the wake of the disclosure, AWS engineer Balbir Singh proposed a patch for the Linux kernel for applications to be able to opt in to flush the L1D cache when a task is switched out. [...] The feature would allow applications on an opt-in basis to call prctl(2) to flush the L1D cache for a task once it leaves the CPU, assuming the hardware supports it.

But, as spotted by Phoronix, Torvalds believes the patch will allow applications that opt in to the patch to degrade CPU performance for other applications.

"Because it looks to me like this basically exports cache flushing instructions to user space, and gives processes a way to just say 'slow down anybody else I schedule with too'," wrote Torvalds yesterday. "In other words, from what I can tell, this takes the crazy 'Intel ships buggy CPU's and it causes problems for virtualization' code (which I didn't much care about), and turns it into 'anybody can opt in to this disease, and now it affects even people and CPU's that don't need it and configurations where it's completely pointless'."


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 2, Interesting) by Anonymous Coward on Friday June 05 2020, @11:43AM (3 children)

    by Anonymous Coward on Friday June 05 2020, @11:43AM (#1003684)

    Time to break up Amazon. Monopolies are wrong!

    Starting Score:    0  points
    Moderation   +2  
       Insightful=1, Interesting=1, Total=2
    Extra 'Interesting' Modifier   0  

    Total Score:   2  
  • (Score: 2) by Bot on Friday June 05 2020, @07:05PM (2 children)

    by Bot (3902) on Friday June 05 2020, @07:05PM (#1003899) Journal

    I only bought Amazon for friends once or twice, since I boycott them for the retarded one click buy patent. The only time I needed one item I scoured the web for the vendor until it popped out and bought direct. Also price had gone down a euro. You don't need Amazon, don't use it.

    If they attempt abusing their monopoly, for example if they somehow turn to be implicated in the old school economy operation based on covid 19, then yeah cut it to pieces.

    Also vote some politician that instead of mewmewing about equality while fucking the middle class, abolishes custom tax deals, abolishes state funding, enforces direct management of army and emergency service providers and prints money at no debt and/or lets pay taxes in something else.

    --
    Account abandoned.
    • (Score: 0) by Anonymous Coward on Saturday June 06 2020, @12:34AM (1 child)

      by Anonymous Coward on Saturday June 06 2020, @12:34AM (#1004017)

      mewmewing about equality while fucking the middle class

      We are the Capitalists.

      You will be proletarianized.

      Your cultural and genetic distinctiveness will be added to our own.

      Resistance is futile.

      • (Score: 0) by Anonymous Coward on Saturday June 06 2020, @04:08AM

        by Anonymous Coward on Saturday June 06 2020, @04:08AM (#1004075)

        OMG don't scare them!