Re: v3.19-rc2: crashes during boot (syslog-ng, rpcbind ...)

Toralf Förster
2014-12-31T08:47:33Z

On 12/30/2014 07:46 PM, Paul Moore wrote:
> On Tuesday, December 30, 2014 09:11:32 AM Paul Moore wrote:
>> On Monday, December 29, 2014 09:18:44 PM Toralf Förster wrote:
>>> On 12/29/2014 08:41 PM, Paul Moore wrote:
>>>> To help verify that I'm heading down the right path, could you share
>>>> your audit configuration as well? If that's not possible, can you at
>>>> least confirm that you using a few audit directory watches?
>>>
>>> Well, it is just a victim system for trinity - but I did not configured
>>> auditd in a special manner - so it is just the plain default configuration
>>> of Gentoo:
>>
>> Okay, thanks for the information; the file related syscall watches are
>> likely what triggered the problem code. Until I've got the fix sorted out,
>> removing the syscall watches or just disabling auditd from starting at boot
>> should workaround the problem.
>
> I still want to go over the below patch a bit more to check a few things, but
> it solves the problem for me and I believe it should solve the problem you are
> seeing as well. Can you give it a try and let me know what happens?
>
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 287b3d3..d834770 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -72,6 +72,8 @@
> #include <linux/fs_struct.h>
> #include <linux/compat.h>
> #include <linux/ctype.h>
> +#include <linux/string.h>
> +#include <uapi/linux/limits.h>
>
> #include "audit.h"
>
> @@ -1862,7 +1864,7 @@ void __audit_inode(struct filename *name, const struct
> dentry *dentry,
>
> list_for_each_entry_reverse(n, &context->names_list, list) {
> /* does the name pointer match? */
> - if (!n->name || n->name->name != name->name)
> + if (!n->name || strcmp(n->name->name, name->name))
> continue;
>
> /* match the correct record type */
> @@ -1881,14 +1883,39 @@ out_alloc:
> n = audit_alloc_name(context, AUDIT_TYPE_UNKNOWN);
> if (!n)
> return;
> - if (name)
> - /* since name is not NULL we know there is already a matching
> - * name record, see audit_getname(), so there must be a type
> - * mismatch; reuse the string path since the original name
> - * record will keep the string valid until we free it in
> - * audit_free_names() */
> - n->name = name;
> + /* unfortunately, while we may have a path name to record with the
> + * inode, we can't always rely on the string lasting until the end of
> + * the syscall so we need to create our own copy, it may fail due to
> + * memory allocation issues, but we do our best */
> + if (name) {
> + /* we can't use getname_kernel() due to size limits */
> + struct filename *new = __getname();
>
> + if (unlikely(!new))
> + goto out;
> +
> + memset(new, 0, sizeof(*new));
> + if ((strlen(name->name) + 1) <= (PATH_MAX - sizeof(*new))) {
> + char *new_name = (char *)(new) + sizeof(*new);
> + new->name = new_name;
> + new->separate = false;
> + } else {
> + /* this looks odd, but is due to final_putname() */
> + struct filename *new2;
> + new2 = kzalloc(sizeof(*new2), GFP_KERNEL);
> + if (unlikely(!new2)) {
> + __putname(new);
> + goto out;
> + }
> + new2->name = (char *)new;
> + new = new2;
> + new->separate = true;
> + }
> + strcpy((char *)new->name, name->name);
> + new->aname = n;
> + n->name = new;
> + n->name_put = true;
> + }
> out:
> if (parent) {
> n->name_len = n->name ? parent_len(n->name->name) : AUDIT_NAME_FULL;
>

n22kvm-clone linux patch -p1 --dry-run < /mnt/t44/devel/kvm.patch
patching file kernel/auditsc.c
patch: **** malformed patch at line 15: dentry *dentry,

--
Toralf
pgp key: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 0076 E94E