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Biederman" , Adrian Reber , Thomas Gleixner , Jens Axboe , Alexei Starovoitov , "linux-fsdevel@vger.kernel.org" , "linux-kernel@vger.kernel.org" , linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, tiozhang , Luis Chamberlain , "Paulo Alcantara (SUSE)" , Sergey Senozhatsky , Frederic Weisbecker , YueHaibing , Paul Moore , Aleksa Sarai , Stefan Roesch , Chao Yu , xu xin , Jeff Layton , Jan Kara , David Hildenbrand , Dave Chinner , Shuah Khan , Elena Reshetova , David Windsor , Mateusz Guzik , Ard Biesheuvel , "Joel Fernandes (Google)" , "Matthew Wilcox (Oracle)" , Hans Liljestrand , Penglei Jiang , Lorenzo Stoakes , Adrian Ratiu , Ingo Molnar , "Peter Zijlstra (Intel)" , Cyrill Gorcunov , Eric Dumazet Subject: Re: [PATCH v17] exec: Fix dead-lock in de_thread with ptrace_attach Message-ID: <20251102161712.GA4273@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-Stat-Signature: 71uyy841c15m3mhkpozwrznayez1kgzf X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: CC8BE1C0002 X-HE-Tag: 1762100536-536745 X-HE-Meta: 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 mKpwBz4o 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 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 08/21, Bernd Edlinger wrote: > > v16: rebased to 6.17-rc2, fixed some minor merge conflicts. > > v17: avoid use of task->in_execve in ptrace_attach. So I guess this version doesn't really differ from v14 I tried to review... (yes, iirc my review wasn't really good, sorry). Perhaps I am wrong, but I still think we need another approach. de_thread() should not wait until all sub-threads are reaped, it should drop cred_guard_mutex earlier. I mean, something like [PATCH V2 1/2] exec: don't wait for zombie threads with cred_guard_mutex held https://lore.kernel.org/lkml/20170213180454.GA2858@redhat.com/ which is hopelessly outdated now. Again, perhaps I am wrong. I'll try to take another look next week. Oleg.