cdev example: Fix deprecated copystr() to prevent kernel panic #1895
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The example cdev module used copystr() inside mydev_read(), which is deprecated according to COPY(9). Although the code compiles, invoking the module causes a kernel page fault. A crash dump larger than 1 GB was generated on 14.3-RELEASE-p5 (amd64 GENERIC). Replacing copystr() with copyout() resolves the issue and the module now behaves as expected.
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bsdimp
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Nov 25, 2025
bsdimp
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Replaced the hardcoded byte count with the len variable in mydev_read(), ensuring the buffer size is used correctly. This follows best practices and prevents potential issues. Signed-off-by: Isa Isoux <[email protected]>
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The example cdev module used copystr() inside mydev_read(), which is deprecated according to COPY(9). Although the code compiles, invoking the module causes a kernel page fault. A crash dump larger than 1 GB was generated on 14.3-RELEASE-p5 (amd64 GENERIC).
Replacing copystr() with copyout() resolves the issue and the module now behaves as expected.
Signed-off-by: Isa Isoux [email protected]