Hi Krzysztof, On Mon, Jan 19, 2026 at 10:16:02AM +0000, Krzysztof Karas wrote: > IGT mmap testing in i915 uses current task's address space to > allocate new userspace mapping, without registering real user > for that address space in mm_struct. > > It was observed that mm->mm_users would occasionally drop to 0 > during tests, which reaped userspace mappings, further leading > to failures upon reading from userland memory. > > Prevent this by artificially increasing mm_users counter for the > duration of the test. > > Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14204 > Signed-off-by: Krzysztof Karas <[email protected]>
Can you please rebase this patch on top of the current trees? > + /* > + * Get a reference to tasks's mm_struct to artificially increase > mm_users > + * and ensure the kernel does not try to clean up the userspace mappings > + * of the current task during the test. > + */ > + mmget_not_zero(current->mm); why mmget_not_zero() and not just mmget()? Overall the patch looks fine to me, I'd like to hear what's Janusz real concern here. Thanks, Andi
