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Received: from 30.27.69.8(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0W63uUr3_1715177617) by smtp.aliyun-inc.com; Wed, 08 May 2024 22:13:40 +0800 Message-ID: <35ab69e7-97cf-4409-b73f-05b00e110ed7@linux.alibaba.com> Date: Wed, 8 May 2024 22:13:37 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH] mm/vmalloc: fix vmalloc which may return null if called with __GFP_NOFAIL From: Gao Xiang To: hailong.liu@oppo.com, akpm@linux-foundation.org, Michal Hocko Cc: urezki@gmail.com, hch@infradead.org, lstoakes@gmail.com, 21cnbao@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, xiang@kernel.org, chao@kernel.org, Oven References: <20240508125808.28882-1-hailong.liu@oppo.com> <404add29-2d3f-45db-9103-0c5b66fb254e@linux.alibaba.com> In-Reply-To: <404add29-2d3f-45db-9103-0c5b66fb254e@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Stat-Signature: ju8r94eihi9rpkqfqp9nsmg4r18mg6wj X-Rspamd-Queue-Id: 5F9181C001E X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1715177623-666064 X-HE-Meta: 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 9cNsvz88 Se1spLAovFyFQcw3IGn6ep/sMaPA+hO7eaIqgMNZV8VPHncyP2GQ47R3LEexYVWdZksohy2HqBYPVvluNbj1wvVfXkG7/KBxKA7Op1UiWWuxvnLpAweJrUNVl+lSXrh8Ysib3mJih4tHnCCaQtqF4+oqeXyOukYFUQf3m1vzkb4DfLcRGjT+mUdzxARrRXLWBX2RD5dEXoAse/cmk2H7PPUOy3sNP6Drj93q4mmsylUorpsESDkcERG/EbJ7Ew1f3vwvI+TnjcnL52mDV4Y+uYBiULz8i3ltvtxr5IqsnL78gMlmhTlP8IYqCcnmFKeCDq9vJlH9F5Mjo7VgQnKl8v0kOpxgsjFSytGWNwFyBN1WCIkM1OsGRRvWWdvAlwFtRu4j7oSAk53j9X2OY1V4jraG0c4TJQ/UdcOJ4qxYzeZd2kgSHWtex0pLCIA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000062, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2024/5/8 21:41, Gao Xiang wrote: > > +Cc Michal, > > On 2024/5/8 20:58, hailong.liu@oppo.com wrote: >> From: "Hailong.Liu" >> >> Commit a421ef303008 ("mm: allow !GFP_KERNEL allocations for kvmalloc") >> includes support for __GFP_NOFAIL, but it presents a conflict with >> commit dd544141b9eb ("vmalloc: back off when the current task is >> OOM-killed"). A possible scenario is as belows: >> >> process-a >> kvcalloc(n, m, GFP_KERNEL | __GFP_NOFAIL) >>      __vmalloc_node_range() >>     __vmalloc_area_node() >>         vm_area_alloc_pages() >>              --> oom-killer send SIGKILL to process-a >>              if (fatal_signal_pending(current)) break; >> --> return NULL; >> >> to fix this, do not check fatal_signal_pending() in vm_area_alloc_pages() >> if __GFP_NOFAIL set. >> >> Reported-by: Oven >> Signed-off-by: Hailong.Liu > > Why taging this as RFC here?  It seems a corner-case fix of > commit a421ef303008 BTW, I guess maybe commit e9c3cda4d86e ("mm, vmalloc: fix high order __GFP_NOFAIL allocations") misses fatal_signal_pending() handling anyway.. > > Thanks, > Gao Xiang >