can: bcm: add locking when updating filter and timer values
In the Linux kernel, the following vulnerability has been resolved: can: bcm: add locking when updating filter and timer values KCSAN detected a simultaneous access to timer values that can be overwritten in bcm_rx_setup() when updating timer and filter content while bcm_rx_handler(), bcm_rx_timeout_handler() or bcm_rx_thr_handler() run concurrently on incoming CAN traffic. Protect the timer (ival1/ival2/kt_ival1/kt_ival2/kt_lastmsg) and filter (nframes/flags/frames/last_frames) updates in bcm_rx_setup() with a new per-op bcm_rx_update_lock, taken with the matching scope in the RX handlers. memcpy_from_msg() is staged into a temporary buffer before the lock is taken, since it can sleep and must not run under a spinlock. hrtimer_cancel() is always called without bcm_rx_update_lock held, since bcm_rx_timeout_handler()/bcm_rx_thr_handler() take the same lock and a running callback would otherwise deadlock against the canceller. Also close a related race: bcm_rx_setup() cleared the RTR flag in the stored reply frame's can_id as a separate, unprotected step after the frame content was already installed, so a concurrent bcm_rx_handler() could transmit a stale reply with CAN_RTR_FLAG still set. Fold that normalization into the initial frame preparation instead (on the staged buffer for updates, directly on op->frames pre-registration for new ops), so the installed frame is always atomically self-consistent. bcm_rx_handler()'s RX_RTR_FRAME check now takes a lock-protected snapshot of
- Products
- Kernel
- Affected versions
- Not specified
- Fixed versions
- 5.10.265, 5.15.216, 6.1.183, 6.12.101, 6.18.42, 6.6.148, 7.1.5
- CVEs
- CVE-2026-72121
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 17:14 UTC · Revision 1
Source evidence
can: bcm: add locking when updating filter and timer values
core-osv · Original sourcePublished 15 Aug 2026, 05:52 UTC
In the Linux kernel, the following vulnerability has been resolved: can: bcm: add locking when updating filter and timer values KCSAN detected a simultaneous access to timer values that can be overwritten in bcm_rx_setup() when updating timer and filter content while bcm_rx_handler(), bcm_rx_timeout_handler() or bcm_rx_thr_handler() run concurrently on incoming CAN traffic. Protect the timer (ival1/ival2/kt_ival1/kt_ival2/kt_lastmsg) and filter (nframes/flags/frames/last_frames) updates in bcm_rx_setup() with a new per-op bcm_rx_update_lock, taken with the matching scope in the RX handlers. memcpy_from_msg() is staged into a temporary buffer before the lock is taken, since it can sleep and must not run under a spinlock. hrtimer_cancel() is always called without bcm_rx_update_lock held, since bcm_rx_timeout_handler()/bcm_rx_thr_handler() take the same lock and a running callback would otherwise deadlock against the canceller. Also close a related race: bcm_rx_setup() cleared the RTR flag in the stored reply frame's can_id as a separate, unprotected step after the frame content was already installed, so a concurrent bcm_rx_handler() could transmit a stale reply with CAN_RTR_FLAG still set. Fold that normalization into the initial frame preparation instead (on the staged buffer for updates, directly on op->frames pre-registration for new ops), so the installed frame is always atomically self-consistent. bcm_rx_handler()'s RX_RTR_FRAME check now takes a lock-protected snapshot of
osv:CVE-2026-72121
Kernel
Fixed versions: 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.5
Complete source record
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