2012/7/5 Al Viro <viro@xxxxxxxxxxxxxxxxxx>: > On Wed, Jul 04, 2012 at 10:39:09AM +0100, Steven Whitehouse wrote: >> Hi, >> >> On Wed, 2012-07-04 at 17:32 +0800, Robin Dong wrote: >> > From: Robin Dong <sanbai@xxxxxxxxxx> >> > >> > When we using lookup_one_len() to search pathname component, it will call __lookup_hash() >> > with variable 'nd' as NULL : >> > >> > --> __lookup_hash ( nd = NULL ) >> > --> lookup_dcache >> > --> d_invalidate >> > --> proc_sys_revalidate >> > >> > the proc_sys_revalidate will use 'nd->flags' before check whether its value is NULL. >> > This will cause kernel panic. >> > >> > Therefore, we should adding check-code for filesystems which directly use nd->flags. >> > >> > Signed-off-by: Robin Dong <sanbai@xxxxxxxxxx> >> >> nd will very shortly no longer be passed to revalidate... see this patch >> in Al's vfs git tree: >> > > Not to mention that anyone who tries to export procfs over nfs deserves Bad Things(tm) > happening to them.... > > IOW, what the hell is your code trying to do? I have found kernel panic on proc_sys_revalidate for using 'nd->flags' with value of 'nd' as NULL when testing overlayfs. I haven't seen the patch (http://git.kernel.org/?p=linux/kernel/git/viro/vfs.git;a=commitdiff;h=282638cce7050592b3d6267ae08ea2573908998c#patch4) before, so.... Sorry for disturbing you. -- -- Best Regard Robin Dong -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
