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a=XiAAW1AwiKB2Y8Wsi+sD2Q==:117 a=XiAAW1AwiKB2Y8Wsi+sD2Q==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=wKuvFiaSGQ0qltdbU6+NXLB8nM8=:19 a=Ol13hO9ccFRV9qXi2t6ftBPywas=:19 a=xqWC_Br6kY4A:10 a=kj9zAlcOel0A:10 a=yJojWOMRYYMA:10 a=GoEa3M9JfhUA:10 a=yPCof4ZbAAAA:8 a=DL7BUCsRM9HRBss6klwA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-ORIG-GUID: cNcB7eKQB22nwNCb-WGYqYniRiJemc8l X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwOTIwMDAzNCBTYWx0ZWRfX3/UaTKVSZbNg ymIWRmMmnX7NHhnrVMCwMYSoeyPnNyR50UNC6BMpn57PI35bebE2PCnJLuOfvqUU0cechMltorn LoZDDtSEXFTSpvpsO7HWk0o8zwCSlBXcBc32nk+rcTQv5gZGwECaUbLE/Ns+DNgPb0Qjzlc+3D+ bEPnQXQm7EadGPKWLr2iD+TxMJCcFlarS9MZCxxKsARAlQBtRvWZKaiC7YfLuIX63jLLsGtNh78 hhYlpoWDIDH8+/3w/JKqGSmKxmAqKY7Fa5ARccLV5gVtK5jSAZeHuT8JiX3/7QYyqcFVcTJRpOV GHt2MXRaEI68PXy6tx3MuGl5rPOEplJfmN/LgMRh0HUPN3vQMiUK+P+aSPi0FbyfBPkEQ4PnIAg TpJnn6mR X-Proofpoint-GUID: cNcB7eKQB22nwNCb-WGYqYniRiJemc8l On Tue, Sep 23, 2025 at 10:41:39AM +0530, viswanath wrote: > On Mon, 22 Sept 2025 at 23:30, Harry Yoo wrote: > > > When bytes > KKMALLOC_MAX_SIZE (8K on my system), kmalloc redirects allocation > > to the buddy allocator, which can allocate up to (PAGE_SIZE << MAX_PAGE_ORDER) > > bytes (4M on my system). > > In include/linux/slab.h, > KMALLOC_MAX_SIZE is ultimately defined as PAGE_SIZE << MAX_PAGE_ORDER and > KMALLOC_MAX_CACHE_SIZE as PAGE_SIZE << 1 > > I was using those definitions Err, you're right :) you mentioned KMALLOC_MAX_SIZE, not KMALLOC_MAX_CACHE_SIZE. Apologies for the confusion. > > Because allocating a page with order > MAX_PAGE_ORDER page is never > > supposed to succeed, the caller of kmalloc should be fixed rather than > > kmalloc itself. > > So, Is it almost never a good idea to add new validation in the allocator code? Yes, because such allocations will always fail and that's never a good thing. > > I think the right fix should be to return -EINVAL in max_vclocks_store() > > if max * sizeof(int) exceeds PAGE_SIZE << MAX_PAGE_ORDER? > > Thanks, I will go ahead with this approach > > Thanks, > Viswanath -- Cheers, Harry / Hyeonggon