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Home CVE Database CVE-2021-47189

CVE-2021-47189

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix memory ordering between normal and ordered work functions Ordered work functions aren\'t guaranteed to be handled by the same thread which executed the normal work functions. The only way execution between normal/ordered functions is synchronized is via the WORK_DONE_BIT, unfortunately the used bitops don\'t guarantee any ordering whatsoever. This manifested as seemingly inexplicable crashes on ARM64, where async_chunk::inode is seen as non-null in async_cow_submit which causes submit_compressed_extents to be called and crash occurs because async_chunk::inode suddenly became NULL. The call trace was similar to: pc : submit_compressed_extents+0x38/0x3d0 lr : async_cow_submit+0x50/0xd0 sp : ffff800015d4bc20 Call trace: submit_compressed_extents+0x38/0x3d0 async_cow_submit+0x50/0xd0 run_ordered_work+0xc8/0x280 btrfs_work_helper+0x98/0x250 process_one_work+0x1f0/0x4ac worker_thread+0x188/0x504 kthread+0x110/0x114 ret_from_fork+0x10/0x18 Fix this by adding respective barrier calls which ensure that all accesses preceding setting of WORK_DONE_BIT are strictly ordered before setting the flag. At the same time add a read barrier after reading of WORK_DONE_BIT in run_ordered_work which ensures all subsequent loads would be strictly ordered after reading the bit. This in turn ensures are all accesses before WORK_DONE_BIT are going to be strictly ordered before any access that can occur in ordered_func.

Priority: --
CVSS v3: --
Component: linux
Publish Date: Apr 10, 2024
Related ID: --
CVSS v2: --
Modified Date: Apr 10, 2024

Find out more about CVE-2021-47189 from the MITRE-CVE dictionary and NIST NVD


Products Affected

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Product Name Status Defect Fixed Downloads
Linux
Wind River Linux LTS 17 Requires LTSS -- -- --
Wind River Linux 8 Requires LTSS -- -- --
Wind River Linux 9 Requires LTSS -- -- --
Wind River Linux 7 Requires LTSS -- -- --
Wind River Linux LTS 21 Investigate -- -- --
Wind River Linux LTS 22 Fixed LIN1022-7515
10.22.33.16 --
Wind River Linux LTS 18 Requires LTSS -- -- --
Wind River Linux LTS 19 Investigate -- -- --
Wind River Linux CD release N/A -- -- --
Wind River Linux 6 Requires LTSS -- -- --
Wind River Linux LTS 23 Not Vulnerable -- -- --
VxWorks
VxWorks 7 Not Vulnerable -- -- --
VxWorks 6.9 Not Vulnerable -- -- --
Helix Virtualization Platform Cert Edition
Helix Virtualization Platform Cert Edition Not Vulnerable -- -- --

Related Products

Product Name Status Defect Fixed Downloads

Notes
Requires LTSS - customers must have active LTSS (Long Term Security Shield) Support to receive up-to-date information about vulnerabilities that may affect legacy software. Please contact your Wind River account team or see https://docs.windriver.com/bundle/Support_and_Maintenance_Supplemental_Terms_and_Conditions and https://support2.windriver.com/index.php?page=plc for more information.
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