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h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JXyJL07acHqlg5PvXgmSd099vExnnoKfJPfUfBFMDr07Ry4Jsnve36oYcnA8pUhgB QAV/xzCd+VNCenzBRvkU+t49ohBOOrxWoXUngWPYCGbRR44HFJs3ZLe7FhrIauahZi WqmyF3ViC8I+m/EEy82JLpYn4eVHPEmNeuoNXmsM= Date: Mon, 18 Aug 2025 07:54:01 +0200 From: Greg Kroah-Hartman To: Gu Bowen Cc: Catalin Marinas , Andrew Morton , stable@vger.kernel.org, linux-mm@kvack.org, Waiman Long , Breno Leitao , John Ogness , Lu Jialin Subject: Re: [PATCH v3] mm: Fix possible deadlock in console_trylock_spinning Message-ID: <2025081846-spongy-cornstalk-ea09@gregkh> References: <20250813085310.2260586-1-gubowen5@huawei.com> <20250813155616.d7e5a832ce7cda7764942d10@linux-foundation.org> <2285c764-e6b3-4cb4-ae12-0bfaa1e67358@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2285c764-e6b3-4cb4-ae12-0bfaa1e67358@huawei.com> X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 0CE60140009 X-Stat-Signature: cp1sd9z8odfrjxmd7tpj1q5f1cnpb5bf X-Rspam-User: X-HE-Tag: 1755496447-678847 X-HE-Meta: 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 939JHrd1 /1Kvujn4Z8q2wljGDaTldN86kG1WrNoUTfNfx3/8Xi8N4Ls/CmQVmDH/aZw5fAUvgyJcpcjBB2eOtQsyKa0eUHXfTukR/fE1BDnBIdLn4hzEYOmtU3sIHoM3n5aGCZM3rfnap4ppUL7yWz+KBsYwmLzjs9sIRJeNgGXHurJ7QvFeN0L4w2DSw0EqLY7Jp7hnJJkB8qSNK5bVqY7LkijTsnhy6bh0BL8gn6G50EQSfbIsvOeN3M+QH3rYuCzw9NC+5FqUOvUbH3Ye0KGBBkYKkAL9TNPUJXahf/Tev4zuBdd2Jt0h22y+GIrcGt4mLSFTPoCBmOOP8mhb+1vb59y9t8jTutVnwugy7c9xL3y9k7+Z8hbjJ3YHYa5vleOVL3dOvUR1sportdNeXM6HG+EXOX9QATShZ1wIyCoxGw2tg4eq6bmSN22K/MZQM0g== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, 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 Mon, Aug 18, 2025 at 10:24:38AM +0800, Gu Bowen wrote: > > > On 8/14/2025 9:08 PM, Catalin Marinas wrote: > > On Thu, Aug 14, 2025 at 10:33:56AM +0800, Gu Bowen wrote: > > > On 8/14/2025 6:56 AM, Andrew Morton wrote: > > > > I'm not sure which kernel version this was against, but kmemleak.c has > > > > changed quite a lot. > > > > > > > > Could we please see a patch against a latest kernel version? Linus > > > > mainline will suit. > > > > > > > > Thanks. > > > > > > I discovered this issue in kernel version 5.10. Afterwards, I reviewed the > > > code of the mainline version and found that this deadlock path no longer > > > exists due to the refactoring of console_lock in v6.2-rc1. For details on > > > the refactoring, you can refer to this link : > > > https://lore.kernel.org/all/20221116162152.193147-1-john.ogness@linutronix.de/. > > > Therefore, theoretically, this issue existed before the refactoring of > > > console_lock. > > > > Oh, so you can no longer hit this issue with mainline. This wasn't > > mentioned (or I missed it) in the commit log. > > > > So this would be a stable-only fix that does not have a correspondent > > upstream. Adding Greg for his opinion. > > > > I have discovered that I made a mistake, this fix patch should be merged > into the mainline. Since we have identified two types of deadlocks, the AA > deadlock [1] and the ABBA deadlock[2], the latter's deadlock path no longer > exists in the mainline due to the 40 patches that refactored console_lock. > However, the AA deadlock issue persists, so I believe this fix should be > applied to the mainline. > > [1] https://lore.kernel.org/all/20250731-kmemleak_lock-v1-1-728fd470198f@debian.org/#t > [2] https://lore.kernel.org/all/20250730094914.566582-1-gubowen5@huawei.com/ Pleasae submit it as a normal patch then. thanks, greg k-h