CVE-2026-64093batman-adv: tp_meter: directly shut down timer on cleanup

Official description

In the Linux kernel, the following vulnerability has been resolved: batman-adv: tp_meter: directly shut down timer on cleanup batadv_tp_sender_cleanup() was calling timer_delete_sync() followed by timer_delete() to guard against the timer handler re-arming itself between the two calls. This double-deletion hack relied on the sending status being set to 0 to suppress re-arming. Replace both calls with a single timer_shutdown_sync(). This function both waits for any running timer callback to complete (like timer_delete_sync()) and permanently disarms the timer so it cannot be re-armed afterwards, making re-arming prevention unconditional and self-documenting. The re-arming property is also required because otherwise: 1. context 0 (batadv_tp_recv_ack()) checks in batadv_tp_reset_sender_timer() if sending is still 1 -> it is 2. context 1 changes in batadv_tp_sender_shutdown() sending to 0 and in this process forces the kthread to stop timer in batadv_tp_sender_cleanup() 3. context 0 continues in batadv_tp_reset_sender_timer() and rearms the timer -> but the reference for it is already gone

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/00bf4bb9947b1190a8be8d9b6a1bcbfa3707785c
• https://git.kernel.org/stable/c/74a76634055462833446684fd526d73c290ea43a
• https://git.kernel.org/stable/c/5bc2d50fb66b46f86543d5153a188eb1486d0b6e
• https://git.kernel.org/stable/c/f86b20ec8d17d77bddc02c5c86cfa2389d84ecff
• https://git.kernel.org/stable/c/770bf0a35f0620b526fd4193889d1e77084e4c43
• https://git.kernel.org/stable/c/933880a8bc9b4042223a79255c0b1021cdc36991
• https://git.kernel.org/stable/c/d5487249a81ea658717614009c8f46acc5b7101a