| Message ID | 20200728163416.556521-3-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/23] fs: refactor do_mount | expand |
On Tue, 28 Jul 2020 at 22:04, Christoph Hellwig <hch@lst.de> wrote: > > Factor out a path_umount helper that takes a struct path * instead of the > actual file name. This will allow to convert the init and devtmpfs code > to properly mount based on a kernel pointer instead of relying on the > implicit set_fs(KERNEL_DS) during early init. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/namespace.c | 40 ++++++++++++++++++---------------------- > 1 file changed, 18 insertions(+), 22 deletions(-) > > diff --git a/fs/namespace.c b/fs/namespace.c > index 6f8234f74bed90..43834b59eff6c3 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -1706,36 +1706,19 @@ static inline bool may_mandlock(void) > } > #endif > > -/* > - * Now umount can handle mount points as well as block devices. > - * This is important for filesystems which use unnamed block devices. > - * > - * We now support a flag for forced unmount like the other 'big iron' > - * unixes. Our API is identical to OSF/1 to avoid making a mess of AMD > - */ > - > -int ksys_umount(char __user *name, int flags) > +static int path_umount(struct path *path, int flags) > { > - struct path path; > struct mount *mnt; > int retval; > - int lookup_flags = LOOKUP_MOUNTPOINT; > > if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW)) > return -EINVAL; > - > if (!may_mount()) > return -EPERM; > > - if (!(flags & UMOUNT_NOFOLLOW)) > - lookup_flags |= LOOKUP_FOLLOW; > - > - retval = user_path_at(AT_FDCWD, name, lookup_flags, &path); > - if (retval) > - goto out; > - mnt = real_mount(path.mnt); > + mnt = real_mount(path->mnt); > retval = -EINVAL; > - if (path.dentry != path.mnt->mnt_root) > + if (path->dentry != path->mnt->mnt_root) > goto dput_and_out; > if (!check_mnt(mnt)) > goto dput_and_out; > @@ -1748,12 +1731,25 @@ int ksys_umount(char __user *name, int flags) > retval = do_umount(mnt, flags); > dput_and_out: > /* we mustn't call path_put() as that would clear mnt_expiry_mark */ > - dput(path.dentry); > + dput(path->dentry); > mntput_no_expire(mnt); > -out: > return retval; > } > > +int ksys_umount(char __user *name, int flags) > +{ > + int lookup_flags = LOOKUP_MOUNTPOINT; > + struct path path; > + int ret; > + > + if (!(flags & UMOUNT_NOFOLLOW)) > + lookup_flags |= LOOKUP_FOLLOW; > + ret = user_path_at(AT_FDCWD, name, lookup_flags, &path); > + if (ret) > + return ret; > + return path_umount(&path, flags); > +} > + > SYSCALL_DEFINE2(umount, char __user *, name, int, flags) > { > return ksys_umount(name, flags); Regressions on linux next 20200803 tag kernel. LTP syscalls test umount03 mount a path for testing and umount failed and retired for 50 times and test exit with warning and following test cases using that mount path failed. LTP syscalls tests failed list, * umount03 * umount2_01 * umount2_02 * umount2_03 * utime06 * copy_file_range01 Summary ------------------------------------------------------------------------ kernel: 5.8.0 git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git branch: master git describe: next-20200803 Test details: https://qa-reports.linaro.org/lkft/linux-next-oe/build/next-20200803 ------------------------------------------------------------------------ test failed log: tst_device.c:262: INFO: Using test device LTP_DEV='/dev/loop0' tst_mkfs.c:90: INFO: Formatting /dev/loop0 with ext2 opts='' extra opts='' mke2fs 1.43.8 (1-Jan-2018) tst_test.c:1246: INFO: Timeout per run is 0h 15m 00s [ 870.449934] EXT4-fs (loop0): mounting ext2 file system using the ext4 subsystem [ 870.454338] EXT4-fs (loop0): mounted filesystem without journal. Opts: (null) [ 870.456412] ext2 filesystem being mounted at /tmp/ltp-YQrzWZNEEy/jVhqum/mntpoint supports timestamps until 2038 (0x7fffffff) umount03.c:35: PASS: umount() fails as expected: EPERM (1) tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 1... tst_device.c:388: INFO: Likely gvfsd-trash is probing newly mounted fs, kill it to speed up tests. tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 2... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 3... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 4... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 5... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 6... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 7... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 8... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 9... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 10... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 11... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 12... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 13... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 14... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 15... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 16... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 17... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 18... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 19... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 20... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 21... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 22... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 23... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 24... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 25... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 26... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 27... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 28... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 29... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 30... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 31... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 32... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 33... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 34... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 35... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 36... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 37... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 38... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 39... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 40... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 41... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 42... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 43... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 44... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 45... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 46... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 47... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 48... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 49... tst_device.c:384: INFO: umount('mntpoint') failed with EBUSY, try 50... tst_device.c:394: WARN: Failed to umount('mntpoint') after 50 retries tst_tmpdir.c:337: WARN: tst_rmdir: rmobj(/tmp/ltp-YQrzWZNEEy/jVhqum) failed: remove(/tmp/ltp-YQrzWZNEEy/jVhqum/mntpoint) failed; errno=16: EBUSY Summary: passed 1 failed 0 skipped 0 warnings 1 mke2fs 1.43.8 (1-Jan-2018) /dev/loop0 is mounted; will not make a filesystem here! umount2_01 0 TINFO : Using test device LTP_DEV='/dev/loop0' umount2_01 0 TINFO : Formatting /dev/loop0 with ext2 opts='' extra opts='' umount2_01 1 TBROK : tst_mkfs.c:103: umount2_01.c:81: mkfs.ext2 failed with 1 umount2_01 2 TBROK : tst_mkfs.c:103: Remaining cases broken mke2fs 1.43.8 (1-Jan-2018) /dev/loop0 is mounted; will not make a filesystem here! umount2_02 0 TINFO : Using test device LTP_DEV='/dev/loop0' umount2_02 0 TINFO : Formatting /dev/loop0 with ext2 opts='' extra opts='' umount2_02 1 TBROK : tst_mkfs.c:103: umount2_02.c:121: mkfs.ext2 failed with 1 umount2_02 2 TBROK : tst_mkfs.c:103: Remaining cases broken mke2fs 1.43.8 (1-Jan-2018) /dev/loop0 is mounted; will not make a filesystem here! umount2_03 0 TINFO : Using test device LTP_DEV='/dev/loop0' umount2_03 0 TINFO : Formatting /dev/loop0 with ext2 opts='' extra opts='' umount2_03 1 TBROK : tst_mkfs.c:103: umount2_03.c:101: mkfs.ext2 failed with 1 umount2_03 2 TBROK : tst_mkfs.c:103: Remaining cases broken mke2fs 1.43.8 (1-Jan-2018) /dev/loop0 is mounted; will not make a filesystem here! utime06 0 TINFO : Using test device LTP_DEV='/dev/loop0' utime06 0 TINFO : Formatting /dev/loop0 with ext2 opts='' extra opts='' utime06 1 TBROK : tst_mkfs.c:103: utime06.c:122: mkfs.ext2 failed with 1 utime06 2 TBROK : tst_mkfs.c:103: Remaining cases broken Steps to reproduce: ------------------------- cd /opt/ltp ./runltp -s umount --> FAILS Above command runs all umount tests. Test case description, Verify that umount(2) returns -1 and sets errno to EPERM if the user is not the super-user. Test case link, https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/umount/umount03.c full test log, https://lkft.validation.linaro.org/scheduler/job/1642287 -- Linaro LKFT https://lkft.linaro.org
On Thu, 6 Aug 2020 at 20:14, Naresh Kamboju <naresh.kamboju@linaro.org> wrote: > > On Tue, 28 Jul 2020 at 22:04, Christoph Hellwig <hch@lst.de> wrote: > > > > Factor out a path_umount helper that takes a struct path * instead of the > > actual file name. This will allow to convert the init and devtmpfs code > > to properly mount based on a kernel pointer instead of relying on the > > implicit set_fs(KERNEL_DS) during early init. > > > > Signed-off-by: Christoph Hellwig <hch@lst.de> > > --- > > fs/namespace.c | 40 ++++++++++++++++++---------------------- > > 1 file changed, 18 insertions(+), 22 deletions(-) > > > > diff --git a/fs/namespace.c b/fs/namespace.c > > index 6f8234f74bed90..43834b59eff6c3 100644 > > --- a/fs/namespace.c > > +++ b/fs/namespace.c <trim> > > Regressions on linux next 20200803 tag kernel. > LTP syscalls test umount03 mount a path for testing and > umount failed and retired for 50 times and test exit with warning > and following test cases using that mount path failed. > > LTP syscalls tests failed list, > * umount03 > * umount2_01 > * umount2_02 > * umount2_03 > * utime06 > * copy_file_range01 The reported issue has been fixed in linux next 20200817 tag by below patch. fs: fix a struct path leak in path_umount Make sure we also put the dentry and vfsmnt in the illegal flags and !may_umount cases. Fixes: 41525f56e256 ("fs: refactor ksys_umount") - Naresh
diff --git a/fs/namespace.c b/fs/namespace.c index 6f8234f74bed90..43834b59eff6c3 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1706,36 +1706,19 @@ static inline bool may_mandlock(void) } #endif -/* - * Now umount can handle mount points as well as block devices. - * This is important for filesystems which use unnamed block devices. - * - * We now support a flag for forced unmount like the other 'big iron' - * unixes. Our API is identical to OSF/1 to avoid making a mess of AMD - */ - -int ksys_umount(char __user *name, int flags) +static int path_umount(struct path *path, int flags) { - struct path path; struct mount *mnt; int retval; - int lookup_flags = LOOKUP_MOUNTPOINT; if (flags & ~(MNT_FORCE | MNT_DETACH | MNT_EXPIRE | UMOUNT_NOFOLLOW)) return -EINVAL; - if (!may_mount()) return -EPERM; - if (!(flags & UMOUNT_NOFOLLOW)) - lookup_flags |= LOOKUP_FOLLOW; - - retval = user_path_at(AT_FDCWD, name, lookup_flags, &path); - if (retval) - goto out; - mnt = real_mount(path.mnt); + mnt = real_mount(path->mnt); retval = -EINVAL; - if (path.dentry != path.mnt->mnt_root) + if (path->dentry != path->mnt->mnt_root) goto dput_and_out; if (!check_mnt(mnt)) goto dput_and_out; @@ -1748,12 +1731,25 @@ int ksys_umount(char __user *name, int flags) retval = do_umount(mnt, flags); dput_and_out: /* we mustn't call path_put() as that would clear mnt_expiry_mark */ - dput(path.dentry); + dput(path->dentry); mntput_no_expire(mnt); -out: return retval; } +int ksys_umount(char __user *name, int flags) +{ + int lookup_flags = LOOKUP_MOUNTPOINT; + struct path path; + int ret; + + if (!(flags & UMOUNT_NOFOLLOW)) + lookup_flags |= LOOKUP_FOLLOW; + ret = user_path_at(AT_FDCWD, name, lookup_flags, &path); + if (ret) + return ret; + return path_umount(&path, flags); +} + SYSCALL_DEFINE2(umount, char __user *, name, int, flags) { return ksys_umount(name, flags);
Factor out a path_umount helper that takes a struct path * instead of the actual file name. This will allow to convert the init and devtmpfs code to properly mount based on a kernel pointer instead of relying on the implicit set_fs(KERNEL_DS) during early init. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/namespace.c | 40 ++++++++++++++++++---------------------- 1 file changed, 18 insertions(+), 22 deletions(-)