Bug 2338209 (CVE-2024-57891) - CVE-2024-57891 kernel: sched_ext: Fix invalid irq restore in scx_ops_bypass()
Summary: CVE-2024-57891 kernel: sched_ext: Fix invalid irq restore in scx_ops_bypass()
Keywords:
Status: NEW
Alias: CVE-2024-57891
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-01-15 14:03 UTC by OSIDB Bzimport
Modified: 2025-02-01 15:05 UTC (History)
4 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2025-01-15 14:03:26 UTC
In the Linux kernel, the following vulnerability has been resolved:

sched_ext: Fix invalid irq restore in scx_ops_bypass()

While adding outer irqsave/restore locking, 0e7ffff1b811 ("scx: Fix raciness
in scx_ops_bypass()") forgot to convert an inner rq_unlock_irqrestore() to
rq_unlock() which could re-enable IRQ prematurely leading to the following
warning:

  raw_local_irq_restore() called with IRQs enabled
  WARNING: CPU: 1 PID: 96 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x30/0x40
  ...
  Sched_ext: create_dsq (enabling)
  pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
  pc : warn_bogus_irq_restore+0x30/0x40
  lr : warn_bogus_irq_restore+0x30/0x40
  ...
  Call trace:
   warn_bogus_irq_restore+0x30/0x40 (P)
   warn_bogus_irq_restore+0x30/0x40 (L)
   scx_ops_bypass+0x224/0x3b8
   scx_ops_enable.isra.0+0x2c8/0xaa8
   bpf_scx_reg+0x18/0x30
  ...
  irq event stamp: 33739
  hardirqs last  enabled at (33739): [<ffff8000800b699c>] scx_ops_bypass+0x174/0x3b8
  hardirqs last disabled at (33738): [<ffff800080d48ad4>] _raw_spin_lock_irqsave+0xb4/0xd8

Drop the stray _irqrestore().


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