On Tue, Jun 19, 2018 at 12:59 PM, Eddie Horng <eddiehorng.tw@xxxxxxxxx> wrote: > Hi Amir, > I'd like to report a file access error case, happened while building a > yocto codebase on overlay mount dir. > After compiling gets error, dmesg shows warning message like: > [13181.958681] Invalid argument reading file caps for > /vol/mnt/m/build/tmp/work/x86_64-linux/gobject-introspection-native/1.50.0-r0/build/.libs/lt-g-ir-compiler > > Mount config is like: > none /vol/mnt/m overlay > rw,relatime,lowerdir=/vol/yocto,upperdir=/vol/mnt/u,workdir=/vol/mnt/w,xino=off > 0 0 > The error accessed file and its dir build/ is created after mount. What is the underlying filesystem? Do you if your system also tries to set security.capability xattr or just tries to read them? > > I don't have simple step to reproduce the case, it just happens soon > or later in the progress of build. > Nearly everytime the error happens in clean build, but not 100% > happening, occasionally build progress can pass without error. > > Cross test on versions and configs: it shows 4.9 and 4.10 don't have > the issue ( 4.11~4.15 are not tested). > - 4.17.0: samefs: reproduced > - 4.17.0: non-samefs: reproduced > - 4.17.0: non-samefs, mount with index=on,xino=on: reproduced > - 4.16.0: non-samefs: reproduced > - 4.9.x and 4.10.x: non-samefs: NOT reproduced > > I tried to trace where the message "Invalid argument reading file caps > ..." comes from, it's like: > handler->get() => ovl_other_xattr_get > fs/xattr.c: __vfs_getxattr (xattr name=security.capability) > handler->get() returns -EINVAL > security/commoncap.c: get_vfs_caps_from_disk > security/commoncap.c: get_file_caps > > Would you suggest where I can check more or which changes I can test? > I would check the change (from v4.14): 8db6c34f1dbc Introduce v3 namespaced file capabilities I suggest that you continue down the rabbit hole to see which check returns -EINVAL, whether inside ovl_xattr_get() or deeper inside nested vfs_getxattr(). Other than that, you can try this overlayfs backport branch: https://github.com/amir73il/linux/commits/overlayfs-4.9.y-17 It contains backported overlayfs patches up to v4.17 based off of v4.9.102. If problem is not reproduced on the backported branch then chances are the problem has to do with interaction between overlayfs and a change to another subsystem (e.g. v3 namespaced file capabilities). Thanks, Amir. -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
