Linux kernel: Samsung serial deadlock from redundant lock
CVE-2026-64528 Published on July 25, 2026
tty: serial: samsung: Remove redundant port lock acquisition in rx helpers
In the Linux kernel, the following vulnerability has been resolved:
tty: serial: samsung: Remove redundant port lock acquisition in rx helpers
Sashiko identified a deadlock when the console flow is engaged [1].
When console flow control is enabled (UPF_CONS_FLOW),
s3c24xx_serial_stop_tx() calls s3c24xx_serial_rx_enable() and
s3c24xx_serial_start_tx() calls s3c24xx_serial_rx_disable().
The serial core framework invokes the .stop_tx() and .start_tx()
callbacks with the port->lock spinlock already held. Furthermore, all
internal driver paths that invoke stop_tx (such as the DMA TX
completion handler s3c24xx_serial_tx_dma_complete() or the PIO TX IRQ
handler s3c24xx_serial_tx_irq()) also acquire port->lock prior to
calling it. (Note that s3c24xx_serial_start_tx() is only invoked by the
serial core).
However, s3c24xx_serial_rx_enable() and s3c24xx_serial_rx_disable()
unconditionally attempt to acquire port->lock again using
uart_port_lock_irqsave(). Since spinlocks are not recursive, this
causes a deadlock on the same CPU when console flow control is engaged.
Remove the redundant lock acquisition from both rx helper functions.
Products Associated with CVE-2026-64528
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Affected Versions
Linux:- Version b497549a035c2a81b71c7a27f2b00c8a16c09423 and below ee9eb72be95490602c493db050c73d925c3a4d74 is affected.
- Version b497549a035c2a81b71c7a27f2b00c8a16c09423 and below 10014eb7eee351f7b587f8ac85830f0c9343cb9a is affected.
- Version b497549a035c2a81b71c7a27f2b00c8a16c09423 and below f4c3e63fa8639aedf96fb200d9939945a9eed51e is affected.
- Version b497549a035c2a81b71c7a27f2b00c8a16c09423 and below a9c22e0f93ba18322a6623ecdda2f0cd858ca350 is affected.
- Version b497549a035c2a81b71c7a27f2b00c8a16c09423 and below 14143ec10d69f42806b5d7b046f0fd1b835831ae is affected.
- Version b497549a035c2a81b71c7a27f2b00c8a16c09423 and below 9fd48937046efc9abb89379d63ee9cc5c661d711 is affected.
- Version b497549a035c2a81b71c7a27f2b00c8a16c09423 and below 9c92b42207978559e32903c3098aaf5c5b5788b2 is affected.
- Version b497549a035c2a81b71c7a27f2b00c8a16c09423 and below a3bb136bff5e6a5e48cdd813246c9c4686feaaa9 is affected.
- Version 2.6.27 is affected.
- Before 2.6.27 is unaffected.
- Version 5.10.259, <= 5.10.* is unaffected.
- Version 5.15.210, <= 5.15.* is unaffected.
- Version 6.1.176, <= 6.1.* is unaffected.
- Version 6.6.143, <= 6.6.* is unaffected.
- Version 6.12.93, <= 6.12.* is unaffected.
- Version 6.18.35, <= 6.18.* is unaffected.
- Version 7.0.12, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.