On Mon, Aug 19, 2013 at 12:30 PM, Richard Genoud <richard.gen...@gmail.com> wrote: > > commit f0c3b5093addc8bfe9fe3a5b01acb7ec7969eafa > "[readdir] convert procfs" introduced a bug on the listing of the proc > file-system. > The return value of proc_readdir() isn't tested anymore in the > proc_root_readdir function. > > This lead to an "interesting" behaviour when we are using the getdents() > system call with a buffer too small: > Instead of failing, it returns the first entries of /proc (enough to > fill the given buffer), plus the PID directories. > > This is not triggered on glibc (as getdents is called with a 32KB > buffer), but on uclibc, the buffer size is only 1KB, thus some proc > entries are missing. > (described more in details here: https://lkml.org/lkml/2013/8/12/288 ) > > Signed-off-by: Richard Genoud <richard.gen...@gmail.com> > --- > [added Linus Torvalds and Andrew Morton in CC since Al Viro seems to be > on holidays and it's starting to getting late in the -rc cycles] > > fs/proc/root.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/fs/proc/root.c b/fs/proc/root.c > index 229e366..e0a790d 100644 > --- a/fs/proc/root.c > +++ b/fs/proc/root.c > @@ -205,7 +205,9 @@ static struct dentry *proc_root_lookup(struct inode * > dir, struct dentry * dentr > static int proc_root_readdir(struct file *file, struct dir_context *ctx) > { > if (ctx->pos < FIRST_PROCESS_ENTRY) { > - proc_readdir(file, ctx); > + int error = proc_readdir(file, ctx); > + if (unlikely(error <= 0)) > + return error; > ctx->pos = FIRST_PROCESS_ENTRY; > }
By my reading that commit (f0c3b5093add) also made proc_readdir always return 0, so with this patch the effect I see is that no pid entries are listed under /proc, breaking ps for instance. I don't see how even the previous version of proc_readdir could return a negative value; looks like 1 and 0 were the only possible return values. Marc -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
