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b=g2SNlN/JczMkJs7a7TXc4W0QX7yYSpNlnPrZuE7kaFJmbzQMgOoLrW1s2M41CddLw+3z+NRPogH0W 4XglbrZawWjkSUgRiHSVydSuoKJSCmyOYSfybPyHbH2qYWGlKN3KDT9md/VWFREdzMc+TXOD0C+X57 kOMxPL1yu6kLig58= X-RM-TagInfo: emlType=0 X-RM-SPAM-FLAG:00000000 Received:from spf.mail.chinamobile.com (unknown[10.188.0.87]) by rmmx-syy-dmz-app06-12006 (RichMail) with SMTP id 2ee66a97e68dce5-6e884; Wed, 02 Sep 2026 17:04:14 +0800 (CST) X-RM-TRANSID:2ee66a97e68dce5-6e884 X-RM-TagInfo: emlType=0 X-RM-SPAM-FLAG:00000000 Received:from localhost.localdomain (unknown[223.108.79.98]) by rmsmtp-syy-appsvr03-12003 (RichMail) with SMTP id 2ee36a97e68d044-f20fa; Wed, 02 Sep 2026 17:04:14 +0800 (CST) X-RM-TRANSID:2ee36a97e68d044-f20fa From: Liu Jing To: akpm@linux-foundation.org Cc: david@kernel.org, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, apopple@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Liu Jing Subject: [PATCH] mempolicy: fix div-by-zero in alloc_pages_bulk_weighted_interleave Date: Wed, 2 Sep 2026 17:04:12 +0800 Message-ID: <20260902090412.16445-1-liujing@cmss.chinamobile.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: A0EB2100008 X-Stat-Signature: czg37bijdhkix7j46i6jg6m5tf45xwsh X-Rspam-User: X-HE-Tag: 1788339858-28549 X-HE-Meta: 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 TiDQo9In hVlus6ab3eo5rIDnK3SFDH069bVv3ExhESIT6+C6LSP3b6werg8s6M0kN8sOApjPRqiG6LURk5wf1rWm4KcmcucMOL4/541OUNXKfHlUGYOqqXbi4QIjDxCn5vWpXegEPsmQQHjCW4A5w3X9Xr0H0MBfIZJ7rBFKEESHRS9e4nBBY2ubFPi18OEgxdGODUh+BvjBAuJm36MCXwR8hAOlGcZsIw/3NJThnHTTnejIUBUMVTxt+Sqk7En9JHaFpwAIHhqw23VfHhopx1t4kZgYfmIAuFmPvfZYQ18caiSKBuurTh/fCSUlQJ7tk5XkpAlfQZEYmSnol7XD91A/GEC5nK8wa29eKnAC4FPePvW0YYsgxeKumceo7hI2uvMgeCDZQzPlOHgn/HV2ZWLvwk05/jGa8Bg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: In alloc_pages_bulk_weighted_interleave(), if the iw_table contains all-zero weights for every node in the policy nodemask, weight_total sums to zero. The subsequent "rem_pages / weight_total" and "rem_pages % weight_total" trigger a divide-by-zero panic. The function already guards against !nnodes but not against a zero weight_total. Add the missing check, freeing the locally allocated weights buffer before returning. Signed-off-by: Liu Jing --- mm/mempolicy.c | 5 +++++ 1 file changed, 5 insertion(+), 0 deletion(-) --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2697,6 +2697,11 @@ /* calculate total, detect system default usage */ for_each_node_mask(node, nodes) weight_total += weights[node]; + + if (!weight_total) { + kfree(weights); + return total_allocated; + } /* * Calculate rounds/partial rounds to minimize __alloc_pages_bulk calls. -- 2.43.0