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CVE-2025-68194 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: media: imon: make send_packet() more robust syzbot is reporting that imon has three problems which result in hung tasks due to forever holding device lock [1]. First problem is that when usb_rx_callback_intf0() once got -EPROTO error after ictx->dev_present_intf0 became true, usb_rx_callback_intf0() resubmits urb after printk(), and resubmitted urb causes usb_rx_callback_intf0() to again get -EPROTO error. This results in printk() flooding (RCU stalls). Alan Stern commented [2] that In theory it's okay to resubmit _if_ the driver has a robust error-recovery scheme (such as giving up after some fixed limit on the number of errors or after some fixed time has elapsed, perhaps with a time delay to prevent a flood of errors). Most drivers don't bother to do this; they simply give up right away. This makes them more vulnerable to short-term noise interference during USB transfers, but in reality such interference is quite rare. There's nothing really wrong with giving up right away. but imon has a poor error-recovery scheme which just retries forever; this behavior should be fixed. Since I'm not sure whether it is safe for imon users to give up upon any error code, this patch takes care of only union of error codes chosen from modules in drivers/media/rc/ directory which handle -EPROTO error (i.e. ir_toy, mceusb and igorplugusb). Second problem is that when usb_rx_callback_intf0() once got -EPROTO error before ictx->dev_present_intf0 becomes true, usb_rx_callback_intf0() always resubmits urb due to commit 8791d63af0cf ("[media] imon: don't wedge hardware after early callbacks"). Move the ictx->dev_present_intf0 test introduced by commit 6f6b90c9231a ("[media] imon: don't parse scancodes until intf configured") to immediately before imon_incoming_packet(), or the first problem explained above happens without printk() flooding (i.e. hung task). Third problem is that when usb_rx_callback_intf0() is not called for some reason (e.g. flaky hardware; the reproducer for this problem sometimes prevents usb_rx_callback_intf0() from being called), wait_for_completion_interruptible() in send_packet() never returns (i.e. hung task). As a workaround for such situation, change send_packet() to wait for completion with timeout of 10 seconds.


Metrics

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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
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URL Source(s) Tag(s)
https://git.kernel.org/stable/c/0213e4175abbb9dfcbf7c197e3817d527f459ad5 kernel.org
https://git.kernel.org/stable/c/26f6a1dd5d81ad61a875a747698da6f27abf389b kernel.org
https://git.kernel.org/stable/c/519737af11c03590819a6eec2ad532cfdb87ea63 kernel.org
https://git.kernel.org/stable/c/667afd4681781f60a644cd0d2ee6c59cb1c36208 kernel.org
https://git.kernel.org/stable/c/8231e80118463be5598daaf266c1c83650f1948b kernel.org
https://git.kernel.org/stable/c/eecd203ada43a4693ce6fdd3a58ae10c7819252c kernel.org
https://git.kernel.org/stable/c/f58ab83b7b7133e6baefe03a46846c4f6ce45e2f kernel.org
https://git.kernel.org/stable/c/f7f3ecb4934fff782fa9bb1cd16e2290c041b22d kernel.org

Weakness Enumeration

CWE-ID CWE Name Source

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2025-68194
NVD Published Date:
12/16/2025
NVD Last Modified:
12/16/2025
Source:
kernel.org