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envelope-from=andrey.drobyshev@virtuozzo.com; helo=EUR05-VI1-obe.outbound.protection.outlook.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 6/2/23 00:18, Michael Tokarev wrote: > 01.06.2023 22:28, Andrey Drobyshev via пишет: >> In case when we're rebasing within one backing chain, and when target >> image >> is larger than old backing file, bdrv_is_allocated_above() ends up >> setting >> *pnum = 0.  As a result, target offset isn't getting incremented, and we >> get stuck in an infinite for loop.  Let's detect this case and proceed >> further down the loop body, as the offsets beyond the old backing size >> need >> to be explicitly zeroed. >> >> Signed-off-by: Andrey Drobyshev > > It looks like you forgot the Reviewed-by: Denis V. Lunev here and > in the subsequent patch. Yes, you're right, thanks for pointing that out. > > Should this be backported to -stable? Not that I've seen this issue, > it's a quite specific and somewhat rare case.. I guess in the vast majority of cases the sizes of images within the same backing chain are equal. But as long as it's legal to have them unequal, a bug remains a bug. > > Thanks, > > /mjt