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h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=CoJeH/FTtYurhrEu7pHCjreAy8kglbRPwM3Bp2MFbNXs5sfimskiQ6GdFaw2b46h5 LFYZjIjC0HLk9VtZElPrV+LCrvrtO/TXriYCzcHxI7ww7m4DuMtGSua9gCijZ8ag5C C1QyPEjg//XpCtccxJ83qTFkU2bPqiwCZUATJ82pjvzmj0HhclIwZdtkBZ4X0D4FpB W2kjXVSW4Jh+gJKkh7n8hluL4QKxxLPc9zkayoPnR79tHeS7TL9oS5+LArhquuyOcO R0f20W9hUcQSALMEMf5u4F5ldJdbIIx8/qJHUPE3ePz+MiGIzk37ns/uj3hE88ZoNC wd/gwuy246nxg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH RFC 11/23] selftests/proc: check that a faulting writer doesn't hold up removal Reply-To: sashiko-reviews@lists.linux.dev To: "Christian Brauner" Cc: "Linus Torvalds" , "Jann Horn" , "Josef Bacik" , "Chris Mason" , "Jeff Layton" , NeilBrown , "Eric Dumazet" , "Thomas Gleixner" , "Al Viro" , "Jonathan Corbet" , "Christoph Hellwig" , "Greg Kroah-Hartman" , "Joel Granados" , "Kees Cook" , "Jan Kara" , "Jan Kara" , linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, coreteam@netfilter.org, kexec@lists.infradead.org, linux-pci@vger.kernel.org, linux-sound@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-hwmon@vger.kernel.org, linux-mm@kvack.org, linux-usb@vger.kernel.org, samba-technical@lists.samba.org, sparclinux@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-serial@vger.kernel.org, "Takashi Iwai" , linux-input@vger.kernel.org, linux-raid@vger.kernel.org, linux-ext4@vger.kernel.org, linux-modules@vger.kernel.org, "Chuck Lever" , tytso@mit.edu, dmitry.torokhov@gmail.com, "Petr Pavlu" , "Anna Schumaker" , yukuai@fygo.io, "Heiko Carstens" , "Vasily Gorbik" , "Alexander Gordeev" , "Christian Borntraeger" In-Reply-To: <20261102-work-procfs-drivers-v1-11-a994bd4d3b1a@kernel.org> References: <20261102-work-procfs-drivers-v1-0-a994bd4d3b1a@kernel.org> <20261102-work-procfs-drivers-v1-11-a994bd4d3b1a@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 03 Nov 2026 15:18:48 +0000 X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Server: rspam09 X-Stat-Signature: 3rctghskqwzekjsr9j3w5jui7dsbnes5 X-Rspamd-Queue-Id: CED3318000D X-Rspam-User: X-HE-Tag: 1793719131-723449 X-HE-Meta: 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 m16inr0D 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [Medium] selftests/proc: fail and leak scsi_debug host without CONFIG_SCS= I_PROC_FS -- commit d0cceed0cde591b286c7977ad630183fc653ded2 Author: Christian Brauner selftests/proc: check that a faulting writer doesn't hold up removal This commit adds a procfs selftest that uses userfaultfd and scsi_debug to verify that a writer faulting during copy-in does not block removal of a /proc/scsi/scsi_debug/ entry and fails with -EIO once the fault is resolved. > diff --git a/tools/testing/selftests/proc/proc-remove-slow-writer.c b/too= ls/testing/selftests/proc/proc-remove-slow-writer.c > new file mode 100644 > index 0000000000000..f69ca75ba87cb > --- /dev/null > +++ b/tools/testing/selftests/proc/proc-remove-slow-writer.c > @@ -0,0 +1,203 @@ [ ... ] > +/* the numbers of the hosts in /proc/scsi/scsi_debug as a bitmap */ > +static int list_hosts(unsigned long *hosts) > +{ > + struct dirent *d; > + DIR *dir; > + > + memset(hosts, 0, MAX_HOSTS / 8); > + dir =3D opendir(HOST_DIR); > + if (!dir) > + /* the directory comes with the first host and goes with the last */ > + return errno =3D=3D ENOENT ? 0 : -errno; [ ... ] > +FIXTURE_SETUP(host) > +{ > + unsigned long before[MAX_HOSTS / HOST_BITS]; > + unsigned long after[MAX_HOSTS / HOST_BITS]; > + > + self->host =3D -1; > + if (access(ADD_HOST, W_OK) && system("modprobe -q scsi_debug add_host= =3D0")) > + SKIP(return, "no scsi_debug"); > + if (access(ADD_HOST, W_OK)) > + SKIP(return, ADD_HOST ": %s", strerror(errno)); > + > + /* host numbers are reused, so look for the one that's new */ > + ASSERT_EQ(list_hosts(before), 0); > + ASSERT_EQ(add_host(1), 0); > + ASSERT_EQ(list_hosts(after), 0); > + self->host =3D new_host(before, after); > + ASSERT_GE(self->host, 0); > + snprintf(self->path, sizeof(self->path), HOST_DIR "/%d", self->host); > +} > + > +FIXTURE_TEARDOWN(host) > +{ > + if (self->host >=3D 0 && !access(self->path, F_OK)) > + add_host(-1); > +} [Severity: Medium] What happens if the test runs on a kernel where scsi_debug is available (CONFIG_SCSI_DEBUG is enabled), but CONFIG_SCSI_PROC_FS is disabled? The sysfs attribute /sys/bus/pseudo/drivers/scsi_debug/add_host is still present and writable without CONFIG_SCSI_PROC_FS, while /proc/scsi is never created. In FIXTURE_SETUP(host), list_hosts(before) sees ENOENT on /proc/scsi/scsi_debug and returns 0, add_host(1) creates a new scsi_debug host in the kernel, and list_hosts(after) still sees ENOENT and returns 0 with an empty bitmap. As a result, new_host(before, after) returns -1 and ASSERT_GE(self->host, 0) fails the test instead of skipping for the missing prerequisite. Because FIXTURE_SETUP(host) aborts with self->host still set to -1, the newly created scsi_debug host is never removed by add_host(-1) and remains leaked. Should FIXTURE_SETUP(host) check that /proc/scsi exists and skip before calling add_host(1)? --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261102-work-procf= s-drivers-v1-0-a994bd4d3b1a@kernel.org?part=3D11