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b=XubAwCv6+ETbPYyk95JCbkpKK5A+JFqtao9ua+CADY8vxNic4QukZaRvgMbdbueZu dEGJTBnNmnjXvWBuiPPxvJZXK1r8ot6BynZQ9rO+SyX/AqRObbBLAdsEnojlAUFntr eQmCxpQVq8bKZd5U4lRQqIPvhS42ofy3tE3U4slpb49itS3F7tCAyTqKVMTPx0/3ab amZ40UQLximBy+DKck5n90zX4/5rVfbMCYf2K3XyUsGcbOX3L5Z1kc80rD9YoAKJlH nJD3FdjWxo2PJvuWcRJjJlxz60fgVH9bbJPUn9+jN23fDkFwzcQ1N2CB7DlEH8ENUk wfJQFPEc+672w== Date: Sat, 14 Nov 2026 17:31:29 +0000 From: "Lorenzo Stoakes (ARM)" To: shao.mingyin@zte.com.cn Cc: surenb@google.com, akpm@linux-foundation.org, linux-mm@kvack.org, hao.ge@linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: snapshot alloc tags in alloc_tag_top_users() to avoid UAF Message-ID: References: <20261115004711126EXlXUnHk7NZz7rkWhDkyP@zte.com.cn> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261115004711126EXlXUnHk7NZz7rkWhDkyP@zte.com.cn> X-Rspamd-Queue-Id: 5A2931C0007 X-Rspamd-Server: rspam12 X-Stat-Signature: 9wy758drns4zfu5s3fzq6uuhnyddwzdu X-Rspam-User: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1794677495-581456 X-HE-Meta: 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 H7EOspWH 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Sun, Nov 15, 2026 at 12:47:11AM +0800, shao.mingyin@zte.com.cn wrote: > From: Shao Mingyin > > mm: snapshot alloc tags in alloc_tag_top_users() to avoid UAF > > alloc_tag_top_users() selects tags under the codetag module-list lock, > then returns raw codetag pointers. __show_mem() dereferences the tags, > their strings and per-CPU counters after that lock has been released. > Concurrent module unloading can invalidate those objects before they > are printed in the OOM or SysRq-m report. > > Copy the selected tags and counters while holding the module-list lock, > and print only the copies. Reuse allocinfo_to_params(), which copies > names into fixed-size buffers and retains at most their last 63 > characters. Preserve the signed comparison used to select the top tags. > > Keep the larger output array static under the existing show_mem lock > to avoid increasing the stack frame. The counters remain approximate > lockless per-CPU observations; the copy protects object lifetime. > > Fixes: 1438d349d16b ("lib: add memory allocations report in show_mem()") > Signed-off-by: Shao Mingyin NAK. this is generated by some AI slopper's script, spamming the kernel. The patches I looked at were wrong/broken, so no to anything from this person. They've sent 300 mails in under four weeks spanniing: ata, scsi, target, ufs, nvme/nvmet, ubifs, ublk, zloop, dm, md, mmc, virtio-blk, mfd, gpio, pwm, spi, PCI, ASoC, ACPI, net, vfs mount, block partitions, and now mm. and 17 series across 7 subsystems over the past 23 hours. We need a way to ban emails from people like this... -- Cheers, Lorenzo