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a=OOZaFjgC48PWsiFpTAqLcw==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=xqWC_Br6kY4A:10 a=kj9zAlcOel0A:10 a=6UeiqGixMTsA:10 a=GoEa3M9JfhUA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=yPCof4ZbAAAA:8 a=u2ey0Y-QUYRKGIaFtsAA:9 a=CjuIK1q_8ugA:10 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-ORIG-GUID: f6Yb9qMTiEEJHKWaoKqSvZSUBTyYKPTk X-Proofpoint-GUID: f6Yb9qMTiEEJHKWaoKqSvZSUBTyYKPTk X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTA1MDEzOCBTYWx0ZWRfXzHlawKOvRzzQ R1e/afaXjr8L+UpCuSpjRqZ1N8ilSQbfx4xmXEsWqy8a7Dxqde2N9p3GP4880ylL6c4yt9sqMnZ +bltOms/5BMpRxP5a/Fi6zTFJ+89rP/rb9fHT8ruTpsCqCv5K0Q62pqIz1AF0au3CiIR0zeuyvS nDPW0ekzwqzBl/41c/sa0yfv54i+fHKYO0n2YDxFjwZYpoFv/y0ZpxsqdOyuUFSEZegG6VHKOIe apyRF/r792dUwVUN9SXeIPbKF1izh3VEKoIfn2160EZJ3sNXIyzveu8PkvRHFdgt7bepUb0Bdys CpzEm7WCyBFvgLoj/oOxmt7UIxQZ5YQM3XU+r4V4djR1GCP/jwlYn2/PV/Glmezuqfh9mX1j63c 23wgNP5JFicoBHiGOtzA+tH8KKif+A== On Mon, Nov 03, 2025 at 01:24:15PM +0100, Vlastimil Babka wrote: > In review of a followup work, Harry noticed a potential infinite loop. > Upon closed inspection, it already exists for kmalloc_nolock() on a > cache with debugging enabled, since commit af92793e52c3 ("slab: > Introduce kmalloc_nolock() and kfree_nolock().") > > When alloc_single_from_new_slab() fails to trylock node list_lock, we > keep retrying to get partial slab or allocate a new slab. If we indeed > interrupted somebody holding the list_lock, the trylock fill fail > deterministically and we end up allocating and defer-freeing slabs > indefinitely with no progress. > > To fix it, fail the allocation if spinning is not allowed. This is > acceptable in the restricted context of kmalloc_nolock(), especially > with debugging enabled. > > Reported-by: Harry Yoo > Closes: https://lore.kernel.org/all/aQLqZjjq1SPD3Fml@hyeyoo/ > Fixes: af92793e52c3 ("slab: Introduce kmalloc_nolock() and kfree_nolock().") > Signed-off-by: Vlastimil Babka > --- > as we discussed in the linked thread, 6.18 hotfix to be included in > slab/for-next-fixes > --- Looks good to me, Reviewed-by: Harry Yoo -- Cheers, Harry / Hyeonggon