From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- Documentation/ABI/testing/sysfs-class-rtc | 91 +++++++++++++++++++++++++++++++ 1 file changed, 91 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-class-rtc (limited to 'Documentation/ABI/testing/sysfs-class-rtc') diff --git a/Documentation/ABI/testing/sysfs-class-rtc b/Documentation/ABI/testing/sysfs-class-rtc new file mode 100644 index 000000000..95984289a --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-rtc @@ -0,0 +1,91 @@ +What: /sys/class/rtc/ +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + The rtc/ class subdirectory belongs to the RTC subsystem. + +What: /sys/class/rtc/rtcX/ +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + The /sys/class/rtc/rtc{0,1,2,3,...} directories correspond + to each RTC device. + +What: /sys/class/rtc/rtcX/date +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + (RO) RTC-provided date in YYYY-MM-DD format + +What: /sys/class/rtc/rtcX/hctosys +Date: September 2009 +KernelVersion: 2.6.32 +Contact: linux-rtc@vger.kernel.org +Description: + (RO) 1 if the RTC provided the system time at boot via the + CONFIG_RTC_HCTOSYS kernel option, 0 otherwise + +What: /sys/class/rtc/rtcX/max_user_freq +Date: October 2007 +KernelVersion: 2.6.24 +Contact: linux-rtc@vger.kernel.org +Description: + (RW) The maximum interrupt rate an unprivileged user may request + from this RTC. + +What: /sys/class/rtc/rtcX/name +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + (RO) The name of the RTC corresponding to this sysfs directory + +What: /sys/class/rtc/rtcX/range +Date: January 2018 +KernelVersion: 4.16 +Contact: linux-rtc@vger.kernel.org +Description: + Valid time range for the RTC, as seconds from epoch, formatted + as [min, max] + +What: /sys/class/rtc/rtcX/since_epoch +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + (RO) RTC-provided time as the number of seconds since the epoch + +What: /sys/class/rtc/rtcX/time +Date: March 2006 +KernelVersion: 2.6.17 +Contact: linux-rtc@vger.kernel.org +Description: + (RO) RTC-provided time in 24-hour notation (hh:mm:ss) + +What: /sys/class/rtc/rtcX/offset +Date: February 2016 +KernelVersion: 4.6 +Contact: linux-rtc@vger.kernel.org +Description: + (RW) The amount which the rtc clock has been adjusted in + firmware. Visible only if the driver supports clock offset + adjustment. The unit is parts per billion, i.e. The number of + clock ticks which are added to or removed from the rtc's base + clock per billion ticks. A positive value makes a day pass more + slowly, longer, and a negative value makes a day pass more + quickly. + +What: /sys/class/rtc/rtcX/wakealarm +Date: February 2007 +KernelVersion: 2.6.20 +Contact: linux-rtc@vger.kernel.org +Description: + (RW) The time at which the clock will generate a system wakeup + event. This is a one shot wakeup event, so must be reset after + wake if a daily wakeup is required. Format is seconds since the + epoch by default, or if there's a leading +, seconds in the + future, or if there is a leading +=, seconds ahead of the + current alarm. -- cgit v1.3.1