In the Linux kernel, the following vulnerability has been resolved:
mm/mglru: fix div-by-zero in vmpressure_calc_level()
evict_folios() uses a second pass to reclaim folios that have gone through
page writeback and become clean before it finishes the first pass, since
folio_rotate_reclaimable() cannot handle those folios due to the
isolation.
The second pass tries to avoid potential double counting by deducting
scan_control->nr_scanned. However, this can result in underflow of
nr_scanned, under a condition where shrink_folio_list() does not increment
nr_scanned, i.e., when folio_trylock() fails.
The underflow can cause the divisor, i.e., scale=scanned+reclaimed in
vmpressure_calc_level(), to become zero, resulting in the following crash:
[exception RIP: vmpressure_work_fn+101]
process_one_work at ffffffffa3313f2b
Since scan_control->nr_scanned has no established semantics, the potential
double counting has minimal risks. Therefore, fix the problem by not
deducting scan_control->nr_scanned in evict_folios().
Metrics
Affected Vendors & Products
References
History
Wed, 11 Sep 2024 13:30:00 +0000
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Metrics |
ssvc
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Thu, 22 Aug 2024 16:15:00 +0000
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First Time appeared |
Linux
Linux linux Kernel |
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Weaknesses | CWE-369 | |
CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
Vendors & Products |
Linux
Linux linux Kernel |
Mon, 19 Aug 2024 19:15:00 +0000
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References |
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Metrics |
threat_severity
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cvssV3_1
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Sat, 17 Aug 2024 09:15:00 +0000
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Description | In the Linux kernel, the following vulnerability has been resolved: mm/mglru: fix div-by-zero in vmpressure_calc_level() evict_folios() uses a second pass to reclaim folios that have gone through page writeback and become clean before it finishes the first pass, since folio_rotate_reclaimable() cannot handle those folios due to the isolation. The second pass tries to avoid potential double counting by deducting scan_control->nr_scanned. However, this can result in underflow of nr_scanned, under a condition where shrink_folio_list() does not increment nr_scanned, i.e., when folio_trylock() fails. The underflow can cause the divisor, i.e., scale=scanned+reclaimed in vmpressure_calc_level(), to become zero, resulting in the following crash: [exception RIP: vmpressure_work_fn+101] process_one_work at ffffffffa3313f2b Since scan_control->nr_scanned has no established semantics, the potential double counting has minimal risks. Therefore, fix the problem by not deducting scan_control->nr_scanned in evict_folios(). | |
Title | mm/mglru: fix div-by-zero in vmpressure_calc_level() | |
References |
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MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-08-17T09:09:24.694Z
Updated: 2024-12-19T09:16:15.409Z
Reserved: 2024-07-30T07:40:12.278Z
Link: CVE-2024-42316
Vulnrichment
Updated: 2024-09-11T12:42:23.395Z
NVD
Status : Analyzed
Published: 2024-08-17T09:15:11.547
Modified: 2024-08-22T15:52:38.520
Link: CVE-2024-42316
Redhat