CVE-2026-90124

Summary

In the Linux kernel, the following vulnerability has been resolved:

irqchip/renesas-rzg2l: Fix loss of interrupt

rzg2l_clear_irq_int() and rzg2l_clear_tint_int() perform a read-modify-write on the ISCR/TSCR status registers to clear the bit for the interrupt just handled. Since these registers are write-0-to-clear per bit, this is racy:

If another interrupt's status bit gets set between the read and the write, that bit is written back as 0 by the software-constructed value, clearing an interrupt that hasn't been serviced yet and losing it.

This can be reproduced by triggering multiple interrupts at once, e.g.:

gpioset -c gpiochip0 355=0 353=0 328=0 352=0

Fix this by writing back only the bit being cleared, with all other bits set to 1, instead of read-modify-writing the whole register. Since 1-bits are left unchanged by hardware, concurrently-set status bits for other interrupts are preserved.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/c043591f03a8111f7d306b8122c444a949486269
• https://git.kernel.org/stable/c/b5ba8b861b5d833394bd23df3f4b59883ef18c88
• https://git.kernel.org/stable/c/3791e242ec2e5a5cd9e010a75ed1125d0e84d394
• https://git.kernel.org/stable/c/38c6831fefde0ff89f8d2dcb924f957a89dec414
• https://git.kernel.org/stable/c/dbecbe23dc606c4af68b4591a41124186f5c1802
• https://git.kernel.org/stable/c/50b10bd0c2d721ad38abd1abe3acdefb6caa0944

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