In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix race in read_extent_buffer_pages()
There are reports from tree-checker that detects corrupted nodes,
without any obvious pattern so possibly an overwrite in memory.
After some debugging it turns out there's a race when reading an extent
buffer the uptodate status can be missed.
To prevent concurrent reads for the same extent buffer,
read_extent_buffer_pages() performs these checks:
/* (1) */
if (test_bit(EXTENT_BUFFER_UPTODATE, &eb->bflags))
return 0;
/* (2) */
if (test_and_set_bit(EXTENT_BUFFER_READING, &eb->bflags))
goto done;
At this point, it seems safe to start the actual read operation. Once
that completes, end_bbio_meta_read() does
/* (3) */
set_extent_buffer_uptodate(eb);
/* (4) */
clear_bit(EXTENT_BUFFER_READING, &eb->bflags);
Normally, this is enough to ensure only one read happens, and all other
callers wait for it to finish before returning. Unfortunately, there is
a racey interleaving:
Thread A | Thread B | Thread C
---------+----------+---------
(1) | |
| (1) |
(2) | |
(3) | |
(4) | |
| (2) |
| | (1)
When this happens, thread B kicks of an unnecessary read. Worse, thread
C will see UPTODATE set and return immediately, while the read from
thread B is still in progress. This race could result in tree-checker
errors like this as the extent buffer is concurrently modified:
BTRFS critical (device dm-0): corrupted node, root=256
block=8550954455682405139 owner mismatch, have 11858205567642294356
expect [256, 18446744073709551360]
Fix it by testing UPTODATE again after setting the READING bit, and if
it's been set, skip the unnecessary read.
[ minor update of changelog ]
References
Configurations
Configuration 1 (hide)
|
History
19 Sep 2025, 15:13
| Type | Values Removed | Values Added |
|---|---|---|
| CWE | CWE-362 | |
| CPE | cpe:2.3:o:linux:linux_kernel:6.9:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 4.7 |
| First Time |
Linux
Linux linux Kernel |
|
| References | () https://git.kernel.org/stable/c/0427c8ef8bbb7f304de42ef51d69c960e165e052 - Patch | |
| References | () https://git.kernel.org/stable/c/2885d54af2c2e1d910e20d5c8045bae40e02fbc1 - Patch | |
| References | () https://git.kernel.org/stable/c/3a25878a3378adce5d846300c9570f15aa7f7a80 - Patch | |
| References | () https://git.kernel.org/stable/c/ef1e68236b9153c27cb7cf29ead0c532870d4215 - Patch |
Information
Published : 2024-05-17 14:15
Updated : 2025-09-19 15:13
NVD link : CVE-2024-35798
Mitre link : CVE-2024-35798
CVE.ORG link : CVE-2024-35798
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-362
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')