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MID_RHS_NOT_FQDN(0.50)[]; HAS_REPLYTO(0.30)[pvorel@suse.cz]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; ARC_NA(0.00)[]; FUZZY_RATELIMITED(0.00)[rspamd.com]; MIME_TRACE(0.00)[0:+]; RCVD_VIA_SMTP_AUTH(0.00)[]; TO_DN_SOME(0.00)[]; MISSING_XM_UA(0.00)[]; RCVD_TLS_ALL(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.cz:replyto,suse.cz:email,imap1.dmz-prg2.suse.org:helo]; REPLYTO_EQ_FROM(0.00)[] X-Virus-Scanned: clamav-milter 1.0.9 at in-6.smtp.seeweb.it X-Virus-Status: Clean Subject: Re: [LTP] [PATCH] userfaultfd05: handle kernels rejecting WP feature in UFFDIO_API X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Petr Vorel Cc: Ricardo Branco , ltp@lists.linux.it Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" Hi Li, Ricardo, > Commit 485a4cd2ba3 ("userfaultfd05: allow TCONF when UFFD-WP is unsupported") > added a TCONF path for missing UFFD-WP, but it relied on checking > uffdio_api.features after a failed ioctl (on RHEL-10). > That is not sufficient: it did not handle the case where UFFDIO_API > succeeds but the kernel does not advertise UFFD_FEATURE_PAGEFAULT_FLAG_WP > in the returned features mask. > So userfaultfd05 still fails on RHEL-9 s390x platform: > userfaultfd05.c:106: TBROK: ioctl(3,((((2U|1U) << (((0+8)+8)+14)) | > (((0xAA)) << (0+8)) | ((((0x00))) << 0) | > ((((sizeof(struct uffdio_register)))) << ((0+8)+8)))),...) > failed: EINVAL (22) > Now, let's handle both behaviours by retrying UFFDIO_API with features=0 > on EINVAL and treating a successful retry as "WP unsupported" (TCONF). > Also check the returned features mask after a successful UFFDIO_API and > skip when WP is not advertised. ... > if (ioctl(uffd, UFFDIO_API, &uffdio_api) < 0) { > - if (!(uffdio_api.features & UFFD_FEATURE_PAGEFAULT_FLAG_WP)) > - tst_brk(TCONF, "UFFD write-protect unsupported"); > + int err = errno; > + if (err == EINVAL) { > + uffdio_api.api = UFFD_API; > + uffdio_api.features = 0; > + > + if (ioctl(uffd, UFFDIO_API, &uffdio_api) == 0) > + tst_brk(TCONF, "UFFD write-protect unsupported"); > + } Wouldn't be better in this case to check kconfig for CONFIG_HAVE_ARCH_USERFAULTFD_WP (untested, but it should work Back to our discussion about how often using kconfig [1]. While I prefer to avoid using it for tristate (kernel might be configured but module missing), but here is just a feature. [1] https://lore.kernel.org/ltp/CAASaF6wOSvi+07Pq5O6+f1Hkrq6WWMgpCaooJxWrO9uOvRM3pw@mail.gmail.com/ But I'm ok with it if you prefer exact check. Reviewed-by: Petr Vorel > - tst_brk(TBROK | TERRNO, "ioctl() on userfaultfd failed"); > + errno = err; > + tst_brk(TBROK | TERRNO, "ioctl(UFFDIO_API) failed"); +1 > } Kind regards, Petr > + if (!(uffdio_api.features & UFFD_FEATURE_PAGEFAULT_FLAG_WP)) > + tst_brk(TCONF, "UFFD write-protect unsupported"); > + > uffdio_register.range.start = (unsigned long) page; > uffdio_register.range.len = page_size; > uffdio_register.mode = UFFDIO_REGISTER_MODE_WP; -- Mailing list info: https://lists.linux.it/listinfo/ltp