| Message ID | 1496649904-1855-1-git-send-email-baijiaju1990@163.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 2017-06-05 at 16:05 +0800, Jia-Ju Bai wrote: > The driver may sleep under a rcu read lock, and function call path > is: > nfs_permission (acquire the lock by rcu_read_lock) > nfs_do_access > nfs_access_add_cache > kmalloc(GFP_KERNEL) --> may sleep > > To fix it, "GFP_KERNEL" is replaced with "GFP_ATOMIC". > > Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com> > --- > fs/nfs/dir.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c > index 32ccd77..7a074db 100644 > --- a/fs/nfs/dir.c > +++ b/fs/nfs/dir.c > @@ -2333,7 +2333,7 @@ static void nfs_access_add_rbtree(struct inode > *inode, struct nfs_access_entry * > > void nfs_access_add_cache(struct inode *inode, struct > nfs_access_entry *set) > { > - struct nfs_access_entry *cache = kmalloc(sizeof(*cache), > GFP_KERNEL); > + struct nfs_access_entry *cache = kmalloc(sizeof(*cache), > GFP_ATOMIC); > if (cache == NULL) > return; > RB_CLEAR_NODE(&cache->rb_node); The RCU locked codepath will not ever hit nfs_access_add_rbtree(). It returns with an error code of -ECHILD after the test of "may_block". Cheers Trond -- Trond Myklebust Linux NFS client maintainer, PrimaryData trond.myklebust@primarydata.com
On 06/05/2017 07:48 PM, Trond Myklebust wrote: > On Mon, 2017-06-05 at 16:05 +0800, Jia-Ju Bai wrote: >> The driver may sleep under a rcu read lock, and function call path >> is: >> nfs_permission (acquire the lock by rcu_read_lock) >> nfs_do_access >> nfs_access_add_cache >> kmalloc(GFP_KERNEL) --> may sleep >> >> To fix it, "GFP_KERNEL" is replaced with "GFP_ATOMIC". >> >> Signed-off-by: Jia-Ju Bai<baijiaju1990@163.com> >> --- >> fs/nfs/dir.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c >> index 32ccd77..7a074db 100644 >> --- a/fs/nfs/dir.c >> +++ b/fs/nfs/dir.c >> @@ -2333,7 +2333,7 @@ static void nfs_access_add_rbtree(struct inode >> *inode, struct nfs_access_entry * >> >> void nfs_access_add_cache(struct inode *inode, struct >> nfs_access_entry *set) >> { >> - struct nfs_access_entry *cache = kmalloc(sizeof(*cache), >> GFP_KERNEL); >> + struct nfs_access_entry *cache = kmalloc(sizeof(*cache), >> GFP_ATOMIC); >> if (cache == NULL) >> return; >> RB_CLEAR_NODE(&cache->rb_node); > The RCU locked codepath will not ever hit nfs_access_add_rbtree(). It > returns with an error code of -ECHILD after the test of "may_block". > > Cheers > Trond Yes, I think you are right. Thanks, Jia-Ju Bai -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 32ccd77..7a074db 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -2333,7 +2333,7 @@ static void nfs_access_add_rbtree(struct inode *inode, struct nfs_access_entry * void nfs_access_add_cache(struct inode *inode, struct nfs_access_entry *set) { - struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_KERNEL); + struct nfs_access_entry *cache = kmalloc(sizeof(*cache), GFP_ATOMIC); if (cache == NULL) return; RB_CLEAR_NODE(&cache->rb_node);
The driver may sleep under a rcu read lock, and function call path is: nfs_permission (acquire the lock by rcu_read_lock) nfs_do_access nfs_access_add_cache kmalloc(GFP_KERNEL) --> may sleep To fix it, "GFP_KERNEL" is replaced with "GFP_ATOMIC". Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com> --- fs/nfs/dir.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)