From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-3.3 required=5.0 tests=MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 11145 invoked from network); 20 Apr 2022 13:55:05 -0000 Received: from mother.openwall.net (195.42.179.200) by inbox.vuxu.org with ESMTPUTF8; 20 Apr 2022 13:55:05 -0000 Received: (qmail 16276 invoked by uid 550); 20 Apr 2022 13:55:03 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 16236 invoked from network); 20 Apr 2022 13:55:02 -0000 Date: Wed, 20 Apr 2022 09:54:49 -0400 From: Rich Felker To: Christian Brauner Cc: =?utf-8?B?546L5rSq5Lqu?= , musl@lists.openwall.com Message-ID: <20220420135449.GC7074@brightrain.aerifal.cx> References: <20220409133044.GL7074@brightrain.aerifal.cx> <20220413072606.44wwkk64xshn5mmm@wittgenstein> <20220413090425.rmprwzpgpztianin@wittgenstein> <20220413140930.GV7074@brightrain.aerifal.cx> <20220414093624.57kdl26xro6vbap4@wittgenstein> <20220420133325.pdppfuc3ijggrgc4@wittgenstein> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220420133325.pdppfuc3ijggrgc4@wittgenstein> User-Agent: Mutt/1.5.21 (2010-09-15) Subject: Re: [musl] Re: add loongarch64 port On Wed, Apr 20, 2022 at 03:33:25PM +0200, Christian Brauner wrote: > On Wed, Apr 20, 2022 at 05:09:08PM +0800, 王洪亮 wrote: > > > > 在 2022/4/14 下午5:36, Christian Brauner 写道: > > > On Wed, Apr 13, 2022 at 10:09:31AM -0400, Rich Felker wrote: > > > > On Wed, Apr 13, 2022 at 03:25:05PM +0200, Arnd Bergmann wrote: > > > > > On Wed, Apr 13, 2022 at 11:04 AM Christian Brauner wrote: > > > > > > On Wed, Apr 13, 2022 at 10:26:06AM +0200, Arnd Bergmann wrote: > > > > > > > The normal rule is that we don't define obsolete system calls in new > > > > > > > architectures when an improved variant has been added, e.g. oldoldstat, > > > > > > > oldstat, stat, newstat and stat64 have all been replaced by statx over > > > > > > > the decades. I was expecting the same to be true for clone(), but if > > > > > > > clone3() is not meant as a replacement, we can keep both around. > > > > > > No, I agree with you on this and would like to only implement clone3() > > > > > > on new architectures. > > > > > > > > > > > > What I'm asking is whether removing the size == 0 check is enough to > > > > > > unblock the missing behavior and whether you'd be on board with removing > > > > > > the check? > > > > > I think that's ok here, since we'd only rely on this for loongarch64 at the > > > > > moment. It would probably need to be documented in the man page > > > > > as a special case though. > > > > I'm okay with removing the check for size==0 (so size==0 will be > > > > allowed) and dropping __NR_clone on new archs, as long as it's noted > > > > in comments/documentation that size==0 is explicitly allowed so nobody > > > > breaks this in the future. > > > Ok, I'll try to have a patch ready early next week since I'm currently > > > out sick. > > > > Hi, > > > > I'm implementing  __NR_clone3 syscall within __clone(). > > > > I have another problem:CLONE_DETACHED > > > > in musl,internal call __clone()(such as __pthread_create()),the input > > parameter flags > > > > has been set CLONE_DETACHED ,in kernel,there is a check in > > clone3_args_valid(), > > > > if the condition met,return false. > > > > How to deal with this problem? > > CLONE_DETACHED is meaningles since Linux on 2.6.2. There really should > be <=2.6.1 living kernel anywhere where CLONE_DETACHED does anything. > I've documented that in detail under [1] as: > > CLONE_DETACHED (historical) > For a while (during the Linux 2.5 development series) > there was a CLONE_DETACHED flag, which caused the parent > not to receive a signal when the child terminated. > Ultimately, the effect of this flag was subsumed under the > CLONE_THREAD flag and by the time Linux 2.6.0 was > released, this flag had no effect. Starting in Linux > 2.6.2, the need to give this flag together with > CLONE_THREAD disappeared. > > This flag is still defined, but it is usually ignored when > calling clone(). However, see the description of > CLONE_PIDFD for some exceptions. > > [1]: https://man7.org/linux/man-pages/man2/clone.2.html > > Would it be possible to drop this flag from musl's pthread_create() > implementation? (Iirc, glibc dropped CLONE_DETACHED in 2004.) I think __clone should just mask it on newer archs. We support Linux 2.6.0 and if lack of CLONE_DETACHED causes bogus signals on 2.6.0 we should keep it. If it can be established that this doesn't happen and that CLONE_DETACHED just affected non-thread clones, we can probably safely drop it. Rich