Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: btmtksdio: fix infinite loop in btmtksdio_txrx_work()
Every once in a while we see a hung btmtksdio_flush() task:
INFO: task kworker/u17:0:189 blocked for more than 122 seconds. __cancel_work_timer+0x3f4/0x460 cancel_work_sync+0x1c/0x2c btmtksdio_flush+0x2c/0x40 hci_dev_open_sync+0x10c4/0x2190 [..]
It all boils down to incorrect time_is_before_jiffies() usage in btmtksdio_txrx_work(). The btmtksdio_txrx_work() loop is expected to be terminated if running for longer than 5HZ. However the timeout check is twisted: time_is_before_jiffies(old_jiffies + 5HZ) evaluates to true when old_jiffies + 5*HZ is in the past i.e. when a timeout has occurred. Using OR with time_is_before_jiffies(txrx_timeout) means that:
- before the 5-second timeout: the condition is
int_status || false, so it loops as long as there are pending interrupts. - after the 5-second timeout: the condition becomes
int_status || true, which is always true.
When the loop becomes infinite btmtksdio_txrx_work() loop never terminates and never releases the SDIO host.
Fix loop termination condition to actually enforce a 5*HZ timeout.
Details
- Affected product:
- Debian 11 ELS
- Affected packages:
- linux @ 5.10.259
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 12 | Planned | — |