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Tue, 16 Jun 2026 03:13:20 -0700 (PDT) Received: from localhost ([43.225.189.75]) by smtp.gmail.com with ESMTPSA id af79cd13be357-9161a03bd31sm1425927085a.34.2026.06.16.03.13.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Jun 2026 03:13:19 -0700 (PDT) Date: Tue, 16 Jun 2026 13:13:13 +0300 From: Dan Carpenter To: Luca Ceresoli Cc: Harshit Mogalapalli , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Amit Kumar Mahapatra , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH] mtd: virt_concat: fix use-after-free in mtd_virt_concat_destroy_joins() Message-ID: References: <20260614081052.1332702-1-harshit.m.mogalapalli@oracle.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260616_031322_898882_7B76AAD9 X-CRM114-Status: GOOD ( 13.24 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Tue, Jun 16, 2026 at 11:51:53AM +0200, Luca Ceresoli wrote: > Issue 2: in mtd_virt_concat_destroy_joins(): > > list_for_each_entry_safe(item, tmp, &concat_node_list, head) { > mtd = &item->concat->mtd; [0] > if (item->concat) { [1] > > At line [0] we dereference item->concat, but at line [1] we apparently > handle the case where item->concat can be NULL. Either [1] is always true > and we can remove the if(), or [1] can be false, so [0] is a bug and should > probably be moved to inside the if(). That's not a dereference on line 0, it's pointer math. So the code works. But a lot of people find the distinction confusing. regards, dan carpenter ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/