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t=1793717313; bh=Y+bptWnMsm9688ffvlZik5wuheu2AuAp4FHdf42AsHs=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=I1YHc/MtZN8GDa7UIDwX7EZbAGqySvUQ9iJMmqHpFghXtS1a7u1snUSRoQZbPgotf rzTS20EjRbQSiraVWbKDq4ZCE++cNFCKRi5Aaifb5wigRVmBCmMaDT7YdKMsDB9tDI EKZhwJ8mtHIR7tJTtUGX8l08CJRlHDCymC+ysWL+tDYTrAJTPYswbt5itzEnPuNwmU 0VvXfu6Z2XZnOqblVvT6wHfP6+iohenxq+H4qRRnC04rlzIf4Onp6n05i56McAI+1Y TqDE/PH+7Hpp+X7zYzUT3YtEtnTjOTA8j+Z92u2V2zFKtu1xuQnbMQURmWoACjuOYC jjzKWAkws/G0g== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH RFC 32/38] selftests/proc: check a sysctl listing while entries come and go 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-bugfixes-v1-32-59422ed3e465@kernel.org> References: <20261102-work-procfs-bugfixes-v1-0-59422ed3e465@kernel.org> <20261102-work-procfs-bugfixes-v1-32-59422ed3e465@kernel.org> Content-Type: text/plain; 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Sashiko AI review found 2 potential issue(= s) to consider: - [Medium] selftests/proc: missing prerequisite skips in sysctl_readdir_set= up() - [Low] selftests/proc: proc-sysctl-readdir-churn duplicates proc-readdir-c= hurn -- commit 9b75f87bfb2fb1adbf5b6ac83f3bfdac725df7f5 Author: Christian Brauner selftests/proc: check a sysctl listing while entries come and go This commit adds a new kselftest binary, proc-sysctl-readdir-churn, to veri= fy that multi-call getdents64() listings of /proc/sys/net/ipv4/conf do not rep= eat or skip entries when a tun network device is registered or unregistered between calls. > diff --git a/tools/testing/selftests/proc/proc-sysctl-readdir-churn.c b/t= ools/testing/selftests/proc/proc-sysctl-readdir-churn.c > new file mode 100644 > index 0000000000000..0e067a3619c44 > --- /dev/null > +++ b/tools/testing/selftests/proc/proc-sysctl-readdir-churn.c > @@ -0,0 +1,147 @@ [ ... ] > +#define CONF_DIR "/proc/sys/net/ipv4/conf" > +#define TUN_NAME "a0" /* sorts before "all" */ > +#define TUN_PATH CONF_DIR "/" TUN_NAME > +#define SMALL_BUF 80 /* ".", ".." and one short name */ > +#define NAMES 64 > + > +static int tun_open(const char *name) > +{ > + struct ifreq ifr =3D {}; > + int fd; > + > + fd =3D open("/dev/net/tun", O_RDWR | O_CLOEXEC); > + if (fd < 0) > + return -1; > + strncpy(ifr.ifr_name, name, IFNAMSIZ - 1); > + ifr.ifr_flags =3D IFF_TUN | IFF_NO_PI; > + if (ioctl(fd, TUNSETIFF, &ifr)) { > + close(fd); > + return -1; > + } > + return fd; > +} > + > +/* one getdents64() into @buf, the names appended to @names */ > +static int list(int fd, char *buf, size_t size, char names[][NAME_MAX + = 1], > + int *n) > +{ > + long ret, off; > + int got =3D 0; > + > + ret =3D syscall(__NR_getdents64, fd, buf, size); > + if (ret < 0) > + return -errno; > + for (off =3D 0; off < ret;) { > + struct dirent64 *d =3D (void *)(buf + off); > + > + if (*n < NAMES) > + strcpy(names[(*n)++], d->d_name); > + got++; > + off +=3D d->d_reclen; > + } > + return got; > +} > + > +static int count(char names[][NAME_MAX + 1], int n, const char *name) > +{ > + int i, c =3D 0; > + > + for (i =3D 0; i < n; i++) > + if (!strcmp(names[i], name)) > + c++; > + return c; > +} > + > +FIXTURE(sysctl_readdir) { > + int dir; > + int n; > + char names[NAMES][NAME_MAX + 1]; > + char buf[65536]; > +}; [Severity: Low] This isn't a bug, but tun_open(), list(), count(), the fixture state in FIXTURE(sysctl_readdir), and the register_in_front and unregister_in_front test flows in tools/testing/selftests/proc/proc-sysctl-readdir-churn.c duplicate the helpers, FIXTURE(proc_readdir), and the add_in_front and remove_in_front test cases in tools/testing/selftests/proc/proc-readdir-chu= rn.c, differing only in the target directory (/proc/sys/net/ipv4/conf vs /proc/net/dev_snmp6) and expected baseline entries (all, default, and lo vs lo). Could this be parameterized in proc-readdir-churn.c using FIXTURE_VARIANT a= nd FIXTURE_VARIANT_ADD instead of introducing a second standalone test file wi= th duplicated helpers and test logic? > + > +FIXTURE_SETUP(sysctl_readdir) > +{ > + if (unshare(CLONE_NEWNET)) > + SKIP(return, "unshare(CLONE_NEWNET): %s", strerror(errno)); > + if (access("/dev/net/tun", F_OK)) > + SKIP(return, "/dev/net/tun: %s", strerror(errno)); > + self->dir =3D open(CONF_DIR, O_RDONLY | O_DIRECTORY | O_CLOEXEC); > + ASSERT_GE(self->dir, 0); > + self->n =3D 0; > +} > + > +FIXTURE_TEARDOWN(sysctl_readdir) > +{ > + close(self->dir); > +} > + > +/* a device registered in front of the position doesn't repeat an entry = */ > +TEST_F(sysctl_readdir, register_in_front) > +{ > + int tun; > + > + /* ".", ".." and "all", "default" doesn't fit */ > + ASSERT_EQ(list(self->dir, self->buf, SMALL_BUF, self->names, &self->n),= 3); > + ASSERT_EQ(count(self->names, self->n, "all"), 1); > + > + tun =3D tun_open(TUN_NAME); > + ASSERT_GE(tun, 0); [Severity: Medium] In FIXTURE_SETUP(sysctl_readdir), opening CONF_DIR (/proc/sys/net/ipv4/conf) is checked with ASSERT_GE(self->dir, 0), whereas proc-readdir-churn.c skips when opening SNMP6_DIR fails: tools/testing/selftests/proc/proc-readdir-churn.c:FIXTURE_SETUP(proc_readdi= r) { ... self->dir =3D open(SNMP6_DIR, O_RDONLY | O_DIRECTORY | O_CLOEXEC); if (self->dir < 0) SKIP(return, SNMP6_DIR ": %s", strerror(errno)); } In addition, FIXTURE_SETUP(sysctl_readdir) only checks access("/dev/net/tun", F_OK). On systems where /dev/net/tun exists as a static device node (for example, created by udev or kmod static-nodes) while CONFIG_TUN is disabled, access("/dev/net/tun", F_OK) succeeds, but open("/dev/net/tun", ...) inside tun_open(TUN_NAME) fails with ENODEV or ENXIO and triggers ASSERT_GE(tun, 0) in register_in_front and unregister_in_front. Since tools/testing/selftests/proc/config only enables CONFIG_PROC_FS=3Dy at this point, will running this test on a kernel without CONFIG_SYSCTL, CONFIG_INET, or CONFIG_TUN fail the test instead of skipping when those prerequisites are unavailable? --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261102-work-procf= s-bugfixes-v1-0-59422ed3e465@kernel.org?part=3D32