Answer in brief
CVE-2021-47189 records a High severity (CVSS 7.8) vulnerability in btrfs: fix memory ordering between normal and ordered work functions. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.16:rc1:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=08a9ff3264181986d1d692a4e6fce3669700c9f8 <bd660a20fea3ec60a49709ef5360f145ec0fe779 || >=08a9ff3264181986d1d692a4e6fce3669700c9f8 <637d652d351fd4f263ef302dc52f3971d314e500 || >=08a9ff3264181986d1d692a4e6fce3669700c9f8 <804a9d239ae9cbe88e861a7cd62319cc6ec7b136 || >=08a9ff3264181986d1d692a4e6fce3669700c9f8 <ed058d735a70f4b063323f1a7bb33cda0f987513 || >=08a9ff3264181986d1d692a4e6fce3669700c9f8 <670f6b3867c8f0f11e5097f353b164cecfec6179 || >=08a9ff3264181986d1d692a4e6fce3669700c9f8 <6adbc07ebcaf8bead08b21687d49e0fc94400987 || >=08a9ff3264181986d1d692a4e6fce3669700c9f8 <47e6f9f69153247109042010f3a77579e9dc61ff || >=08a9ff3264181986d1d692a4e6fce3669700c9f8 <45da9c1767ac31857df572f0a909fbe88fd5a7e9 | bd660a20fea3ec60a49709ef5360f145ec0fe779, 637d652d351fd4f263ef302dc52f3971d314e500, 804a9d239ae9cbe88e861a7cd62319cc6ec7b136, ed058d735a70f4b063323f1a7bb33cda0f987513, 670f6b3867c8f0f11e5097f353b164cecfec6179, 6adbc07ebcaf8bead08b21687d49e0fc94400987, 47e6f9f69153247109042010f3a77579e9dc61ff, 45da9c1767ac31857df572f0a909fbe88fd5a7e9 |
| Linux/Linuxgeneric | 3.15 | Not reported |
Published upstream
Apr 10, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 4, 2026
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 <registers omitted for brevity> 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.
Quoted source text, attributed separately from HOL analysis.