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Biederman" , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2] posix-cpu-timers: Dequeue per-thread timers before exchange_tids() In-Reply-To: References: <875x0qclcx.ffs@fw13> Date: Tue, 01 Sep 2026 16:50:39 +0200 Message-ID: <87qzjdauv4.ffs@fw13> MIME-Version: 1.0 Content-Type: text/plain X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 390BA120006 X-Stat-Signature: kitr7bx1kxsabyekkgoqedp8toxjwcfd X-HE-Tag: 1788274244-117425 X-HE-Meta: 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 zKDT4m8m 8vPaBjl27o9OVsISf+1bgaRdvjIiiBSWQArQ+eRMoCl+hplWLhE3ebCvRG9F9ne9VCrAY6uhLgrpcDKN+YiXSbQFax67o3rIWhRmHizovYdSNKf3BmU8UP/wFUxRP3bCK0zW4n/6Vc+DNJZcjdaIUaHqmtaYYtpMvR8NzwS5Uw9FILo4OK1gBSu4SIgaQvCB0MjkfdT41GLDW7QyjejzmtgYNIpe9H1EoBBfAV1/5tynzhIauZUD+u7u99UZaFspFZU+oiTYaLmFH1crlK6tPrIOqNBMIbu32mXp3C0YYcRn+fMMtNF8EJRFFnruC2B5LlemJ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Aug 31 2026 at 20:24, Oleg Nesterov wrote: > On 08/31, Thomas Gleixner wrote: >> >> On Wed, Aug 26 2026 at 14:55, Oleg Nesterov wrote: >> > Can we move posix_cpu_timers_exit() or the whole CONFIG_POSIX_TIMERS >> > sequence in begin_new_exec() up, right after de_thread() before the >> > "if (retval)" check? >> >> Yes, but that does not buy us anything. > > I didn't mean this makes sense, I just tried to understand the Hyunwoo's > fix, in particular the placement of additional posix_cpu_timers_exit(). Fair enough. But as I was staring at it some more, I thought more about it. Yes, we can do: ret = de_thread() if (ret) goto out; mop_up_posix_timers(); de_thread() only returns failure _before_ the TID swap, so that's safe and spares sprinkling this extra invocation into de_thread(). What a mess.