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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-72118

can: bcm: fix CAN frame rx/tx statistics

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: can: bcm: fix CAN frame rx/tx statistics KCSAN detected a data race within the bcm_rx_handler() when two CAN frames have been simultaneously received and processed in a single rx op by two different CPUs. Use atomic operations with (signed) long data types to access the statistics in the hot path to fix the KCSAN complaint. Additionally simplify the update and check of statistics overflow by using the atomic operations in separate bcm_update_[rx|tx]_stats() functions. The rx variant runs under bcm_rx_update_lock to prevent races when resetting the two rx counters; the tx variant runs under bcm_tx_lock and only needs to guard its own counter's overflow. As the rx path resets its values already at LONG_MAX / 100, there is no conflict between the two locking domains (bcm_rx_update_lock vs. bcm_tx_lock) even for ops that use both paths. The rx statistics update and the frames_filtered update in bcm_rx_changed() were previously performed in two separate bcm_rx_update_lock sections. For an rx op subscribed on all interfaces (ifindex == 0), bcm_rx_handler() can run concurrently on different CPUs, so a counter reset by one CPU between these two sections could leave frames_filtered larger than frames_abs on another CPU, producing a bogus (even negative) reduction percentage in procfs. Update the statistics in the same critical section as bcm_rx_changed() to close this gap, which also removes the now unneeded extra lock/unlock pair around the traffic_flags calculation.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • ffd980f976e7fd666c2e61bf8ab35107efd11828 to < 640acf3566fc897065127001be875ebc5401c218affected
  • ffd980f976e7fd666c2e61bf8ab35107efd11828 to < 47fca0d1620f2d4fab0677564989ef2b9c225c66affected
  • ffd980f976e7fd666c2e61bf8ab35107efd11828 to < fd75884eae40a7be47867cbfc9fc84a80bb8ddb4affected
  • ffd980f976e7fd666c2e61bf8ab35107efd11828 to < 8b2783172d92edd650de6006ebd1c800937021abaffected
  • ffd980f976e7fd666c2e61bf8ab35107efd11828 to < 970caff5c1a63702c80e08d920256bcb5f88ecc5affected
  • ffd980f976e7fd666c2e61bf8ab35107efd11828 to < 8104bcdb2612fdda95169ddc3b49747b2ff98d24affected
  • ffd980f976e7fd666c2e61bf8ab35107efd11828 to < df47f07cdc801a6afe05a486b5a343c3e532a93caffected
  • ffd980f976e7fd666c2e61bf8ab35107efd11828 to < e6c24ba95fc3f1b5e1dcd28b1c6e59ef61a9daa5affected

Linux Linux

Default version status: affected

  • 2.6.25affected
  • 0 to < 2.6.25unaffected
  • 5.10.265 to ≤ 5.10.*unaffected
  • 5.15.216 to ≤ 5.15.*unaffected
  • 6.1.183 to ≤ 6.1.*unaffected
  • 6.6.148 to ≤ 6.6.*unaffected
  • 6.12.101 to ≤ 6.12.*unaffected
  • 6.18.42 to ≤ 6.18.*unaffected
  • 7.1.5 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References