In the Linux kernel, the following vulnerability has been resolved:
flex_proportions: make fprop_new_period() hardirq safe
Bernd has reported a lockdep splat from flexible proportions code that is
essentially complaining about the following race:
<timer fires>
run_timer_softirq - we are in softirq context
call_timer_fn
writeout_period
fprop_new_period
write_seqcount_begin(&p->sequence);
<hardirq is raised>
...
blk_mq_end_request()
blk_update_request()
ext4_end_bio()
folio_end_writeback()
__wb_writeout_add()
__fprop_add_percpu_max()
if (unlikely(max_frac < FPROP_FRAC_BASE)) {
fprop_fraction_percpu()
seq = read_seqcount_begin(&p->sequence);
- sees odd sequence so loops indefinitely
Note that a deadlock like this is only possible if the bdi has configured
maximum fraction of writeout throughput which is very rare in general but
frequent for example for FUSE bdis. To fix this problem we have to make
sure write section of the sequence counter is irqsafe.
flex_proportions: make fprop_new_period() hardirq safe
Bernd has reported a lockdep splat from flexible proportions code that is
essentially complaining about the following race:
<timer fires>
run_timer_softirq - we are in softirq context
call_timer_fn
writeout_period
fprop_new_period
write_seqcount_begin(&p->sequence);
<hardirq is raised>
...
blk_mq_end_request()
blk_update_request()
ext4_end_bio()
folio_end_writeback()
__wb_writeout_add()
__fprop_add_percpu_max()
if (unlikely(max_frac < FPROP_FRAC_BASE)) {
fprop_fraction_percpu()
seq = read_seqcount_begin(&p->sequence);
- sees odd sequence so loops indefinitely
Note that a deadlock like this is only possible if the bdi has configured
maximum fraction of writeout throughput which is very rare in general but
frequent for example for FUSE bdis. To fix this problem we have to make
sure write section of the sequence counter is irqsafe.
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Sat, 14 Feb 2026 16:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: flex_proportions: make fprop_new_period() hardirq safe Bernd has reported a lockdep splat from flexible proportions code that is essentially complaining about the following race: <timer fires> run_timer_softirq - we are in softirq context call_timer_fn writeout_period fprop_new_period write_seqcount_begin(&p->sequence); <hardirq is raised> ... blk_mq_end_request() blk_update_request() ext4_end_bio() folio_end_writeback() __wb_writeout_add() __fprop_add_percpu_max() if (unlikely(max_frac < FPROP_FRAC_BASE)) { fprop_fraction_percpu() seq = read_seqcount_begin(&p->sequence); - sees odd sequence so loops indefinitely Note that a deadlock like this is only possible if the bdi has configured maximum fraction of writeout throughput which is very rare in general but frequent for example for FUSE bdis. To fix this problem we have to make sure write section of the sequence counter is irqsafe. | |
| Title | flex_proportions: make fprop_new_period() hardirq safe | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-02-14T16:01:31.465Z
Reserved: 2026-01-13T15:37:45.981Z
Link: CVE-2026-23168
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-02-14T16:15:57.023
Modified: 2026-02-14T16:15:57.023
Link: CVE-2026-23168
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.