On Fri, Apr 1, 2022 at 10:27 AM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > > The patch titled > Subject: nfs42: use a specific kmem_cache to allocate nfs4_xattr_entry > has been added to the -mm tree. Its filename is > nfs42-use-a-specific-kmem_cache-to-allocate-nfs4_xattr_entry.patch > > This patch should soon appear at > https://ozlabs.org/~akpm/mmots/broken-out/nfs42-use-a-specific-kmem_cache-to-allocate-nfs4_xattr_entry.patch > and later at > https://ozlabs.org/~akpm/mmotm/broken-out/nfs42-use-a-specific-kmem_cache-to-allocate-nfs4_xattr_entry.patch > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** > > The -mm tree is included into linux-next and is updated > there every 3-4 working days > > ------------------------------------------------------ > From: Muchun Song <songmuchun@xxxxxxxxxxxxx> > Subject: nfs42: use a specific kmem_cache to allocate nfs4_xattr_entry > > Fixes a null-pointer deref in nfs4. > > If we want to add the allocated objects to its list_lru, we should use > kmem_cache_alloc_lru() to allocate objects. So intruduce > nfs4_xattr_entry_cachep which is used to allocate nfs4_xattr_entry. > > Link: https://lkml.kernel.org/r/164876616694.25542.14010655277238655246@xxxxxxxxxxxxxxxxxxxxx > Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx> > Tested-by: NeilBrown <neilb@xxxxxxx> > Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> My bad. I think this patch could be dropped. I have looked at the latest code. I found the following commit has removed GFP_ACCOUNT on allocation. 5c60e89e71f8 ("NFSv4.2: Fix up an invalid combination of memory allocation flags") But this commit forgot to remove SLAB_ACCOUNT when creating nfs4_xattr_cache_cachep (I think it is a bug). So I think the following patch could work properly. I'll send a new patch to fix this issue. Thanks. diff --git a/fs/nfs/nfs42xattr.c b/fs/nfs/nfs42xattr.c index ad3405c64b9e..e7b34f7e0614 100644 --- a/fs/nfs/nfs42xattr.c +++ b/fs/nfs/nfs42xattr.c @@ -997,7 +997,7 @@ int __init nfs4_xattr_cache_init(void) nfs4_xattr_cache_cachep = kmem_cache_create("nfs4_xattr_cache_cache", sizeof(struct nfs4_xattr_cache), 0, - (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|SLAB_ACCOUNT), + (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD), nfs4_xattr_cache_init_once); if (nfs4_xattr_cache_cachep == NULL) return -ENOMEM;
