CVSS3
Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
Low
EPSS
Percentile
9.6%
In the Linux kernel, the following vulnerability has been resolved:
workqueue: Fix spruious data race in __flush_work()
When flushing a work item for cancellation, __flush_work() knows that it
exclusively owns the work item through its PENDING bit. 134874e2eee9
(“workqueue: Allow cancel_work_sync() and disable_work() from atomic
contexts on BH work items”) added a read of @work->data to determine whether
to use busy wait for BH work items that are being canceled. While the read
is safe when @from_cancel, @work->data was read before testing @from_cancel
to simplify code structure:
data = *work_data_bits(work);
if (from_cancel &&
!WARN_ON_ONCE(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_BH)) {
While the read data was never used if !@from_cancel, this could trigger
KCSAN data race detection spuriously:
==================================================================
BUG: KCSAN: data-race in __flush_work / __flush_work
write to 0xffff8881223aa3e8 of 8 bytes by task 3998 on cpu 0:
instrument_write include/linux/instrumented.h:41 [inline]
___set_bit include/asm-generic/bitops/instrumented-non-atomic.h:28 [inline]
insert_wq_barrier kernel/workqueue.c:3790 [inline]
start_flush_work kernel/workqueue.c:4142 [inline]
__flush_work+0x30b/0x570 kernel/workqueue.c:4178
flush_work kernel/workqueue.c:4229 [inline]
…
read to 0xffff8881223aa3e8 of 8 bytes by task 50 on cpu 1:
__flush_work+0x42a/0x570 kernel/workqueue.c:4188
flush_work kernel/workqueue.c:4229 [inline]
flush_delayed_work+0x66/0x70 kernel/workqueue.c:4251
…
value changed: 0x0000000000400000 -> 0xffff88810006c00d
Reorganize the code so that @from_cancel is tested before @work->data is
accessed. The only problem is triggering KCSAN detection spuriously. This
shouldn’t need READ_ONCE() or other access qualifiers.
No functional changes.
Vendor | Product | Version | CPE |
---|---|---|---|
linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
linux | linux_kernel | 6.11 | cpe:2.3:o:linux:linux_kernel:6.11:rc1:*:*:*:*:*:* |
linux | linux_kernel | 6.11 | cpe:2.3:o:linux:linux_kernel:6.11:rc2:*:*:*:*:*:* |
linux | linux_kernel | 6.11 | cpe:2.3:o:linux:linux_kernel:6.11:rc3:*:*:*:*:*:* |
linux | linux_kernel | 6.11 | cpe:2.3:o:linux:linux_kernel:6.11:rc4:*:*:*:*:*:* |
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"kernel/workqueue.c"
],
"versions": [
{
"version": "134874e2eee9",
"lessThan": "91d09642127a",
"status": "affected",
"versionType": "git"
},
{
"version": "134874e2eee9",
"lessThan": "8bc35475ef1a",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"kernel/workqueue.c"
],
"versions": [
{
"version": "6.10",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.10",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.10.7",
"lessThanOrEqual": "6.10.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.11",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]