From 1039bffd6ae9c75b42b7d148d6c1106134107b66 Mon Sep 17 00:00:00 2001 From: Xie Yuanbin Date: Tue, 28 Jul 2026 03:16:42 +0100 Subject: ARM: 9485/1: mm: acquire mmap write lock around show_pte() for user faults When CONFIG_DEBUG_USER=y, and cmdline "user_debug=31" is set, a user fault may trigger show_pte() without any lock. If another thread in the same process concurrently calls munmap(), the page table pages may be freed while show_pte() is still traversing them, causing a use-after-free in show_pte(). If CONFIG_ARM_LPAE=y, this may cause a kernel panic if the pages table of PMD are freed when show_pte() is running. Acquire mmap_write_lock() around show_pte() for user faults to fix the contention. For user faults, additionally restrict that show_pte() is called only when the addr is a user-space address (addr < TASK_SIZE). This is because the lock of tsk->mm only protects the virtual memory of user address space, furthermore, dumping the page tables of a kernel-space address for user faults is unnecessary and may have security implications. Keep everything unchanged for kernel faults, because the kernel is already in the "oops" state, acquiring a lock may risk a deadlock. Co-developed-by: Qi Xi Fixes: 6d021b724481 ("ARM: dump pgd, pmd and pte states on unhandled data abort faults") Link: https://lore.kernel.org/20260716014022.2823-1-xieyuanbin1@huawei.com Acked-by: Lorenzo Stoakes (ARM) Reviewed-by: Linus Walleij Signed-off-by: Qi Xi Signed-off-by: Xie Yuanbin Signed-off-by: Russell King --- .../ABI/testing/sysfs-class-led-trigger-netdev | 192 +++++++++++++++++++++ 1 file changed, 192 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-led-trigger-netdev (limited to 'Documentation/ABI/testing/sysfs-class-led-trigger-netdev') diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-netdev b/Documentation/ABI/testing/sysfs-class-led-trigger-netdev new file mode 100644 index 000000000..ed46b37ab --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-led-trigger-netdev @@ -0,0 +1,192 @@ +What: /sys/class/leds//device_name +Date: Dec 2017 +KernelVersion: 4.16 +Contact: linux-leds@vger.kernel.org +Description: + Specifies the network device name to monitor. + +What: /sys/class/leds//interval +Date: Dec 2017 +KernelVersion: 4.16 +Contact: linux-leds@vger.kernel.org +Description: + Specifies the duration of the LED blink in milliseconds. + Defaults to 50 ms. + + When offloaded is true, the interval value MUST be set to the + default value and cannot be changed. + Trying to set any value in this specific mode will return + an EINVAL error. + +What: /sys/class/leds//link +Date: Dec 2017 +KernelVersion: 4.16 +Contact: linux-leds@vger.kernel.org +Description: + Signal the link state of the named network device. + + If set to 0 (default), the LED's normal state is off. + + If set to 1, the LED's normal state reflects the link state + of the named network device. + Setting this value also immediately changes the LED state. + + +What: /sys/class/leds//tx +Date: Dec 2017 +KernelVersion: 4.16 +Contact: linux-leds@vger.kernel.org +Description: + Signal transmission of data on the named network device. + + If set to 0 (default), the LED will not blink on transmission. + + If set to 1, the LED will blink for the milliseconds specified + in interval to signal transmission. + + When offloaded is true, the blink interval is controlled by + hardware and won't reflect the value set in interval. + +What: /sys/class/leds//rx +Date: Dec 2017 +KernelVersion: 4.16 +Contact: linux-leds@vger.kernel.org +Description: + Signal reception of data on the named network device. + + If set to 0 (default), the LED will not blink on reception. + + If set to 1, the LED will blink for the milliseconds specified + in interval to signal reception. + + When offloaded is true, the blink interval is controlled by + hardware and won't reflect the value set in interval. + +What: /sys/class/leds//offloaded +Date: Jun 2023 +KernelVersion: 6.5 +Contact: linux-leds@vger.kernel.org +Description: + Communicate whether the LED trigger modes are offloaded to + hardware or whether software fallback is used. + + If 0, the LED is using software fallback to blink. + + If 1, the LED blinking in requested mode is offloaded to + hardware. + +What: /sys/class/leds//link_10 +Date: Jun 2023 +KernelVersion: 6.5 +Contact: linux-leds@vger.kernel.org +Description: + Signal the link speed state of 10Mbps of the named network device. + + If set to 0 (default), the LED's normal state is off. + + If set to 1, the LED's normal state reflects the link state + speed of 10MBps of the named network device. + Setting this value also immediately changes the LED state. + + Present only if the named network device supports 10Mbps link speed. + +What: /sys/class/leds//link_100 +Date: Jun 2023 +KernelVersion: 6.5 +Contact: linux-leds@vger.kernel.org +Description: + Signal the link speed state of 100Mbps of the named network device. + + If set to 0 (default), the LED's normal state is off. + + If set to 1, the LED's normal state reflects the link state + speed of 100Mbps of the named network device. + Setting this value also immediately changes the LED state. + + Present only if the named network device supports 100Mbps link speed. + +What: /sys/class/leds//link_1000 +Date: Jun 2023 +KernelVersion: 6.5 +Contact: linux-leds@vger.kernel.org +Description: + Signal the link speed state of 1000Mbps of the named network device. + + If set to 0 (default), the LED's normal state is off. + + If set to 1, the LED's normal state reflects the link state + speed of 1000Mbps of the named network device. + Setting this value also immediately changes the LED state. + + Present only if the named network device supports 1000Mbps link speed. + +What: /sys/class/leds//link_2500 +Date: Nov 2023 +KernelVersion: 6.8 +Contact: linux-leds@vger.kernel.org +Description: + Signal the link speed state of 2500Mbps of the named network device. + + If set to 0 (default), the LED's normal state is off. + + If set to 1, the LED's normal state reflects the link state + speed of 2500Mbps of the named network device. + Setting this value also immediately changes the LED state. + + Present only if the named network device supports 2500Mbps link speed. + +What: /sys/class/leds//link_5000 +Date: Nov 2023 +KernelVersion: 6.8 +Contact: linux-leds@vger.kernel.org +Description: + Signal the link speed state of 5000Mbps of the named network device. + + If set to 0 (default), the LED's normal state is off. + + If set to 1, the LED's normal state reflects the link state + speed of 5000Mbps of the named network device. + Setting this value also immediately changes the LED state. + + Present only if the named network device supports 5000Mbps link speed. + +What: /sys/class/leds//link_10000 +Date: Nov 2023 +KernelVersion: 6.8 +Contact: linux-leds@vger.kernel.org +Description: + Signal the link speed state of 10000Mbps of the named network device. + + If set to 0 (default), the LED's normal state is off. + + If set to 1, the LED's normal state reflects the link state + speed of 10000Mbps of the named network device. + Setting this value also immediately changes the LED state. + + Present only if the named network device supports 10000Mbps link speed. + +What: /sys/class/leds//half_duplex +Date: Jun 2023 +KernelVersion: 6.5 +Contact: linux-leds@vger.kernel.org +Description: + Signal the link half duplex state of the named network device. + + If set to 0 (default), the LED's normal state is off. + + If set to 1, the LED's normal state reflects the link half + duplex state of the named network device. + Setting this value also immediately changes the LED state. + +What: /sys/class/leds//full_duplex +Date: Jun 2023 +KernelVersion: 6.5 +Contact: linux-leds@vger.kernel.org +Description: + Signal the link full duplex state of the named network device. + + If set to 0 (default), the LED's normal state is off. + + If set to 1, the LED's normal state reflects the link full + duplex state of the named network device. + Setting this value also immediately changes the LED state. -- cgit v1.3.1