From: Eric Biggers <ebiggers@xxxxxxxxxx>
commit e5bfad3d7acc5702f32aafeb388362994f4d7bd0 upstream.
inode_smack::smk_lock is taken during smack_d_instantiate(), which is
called during a filesystem transaction when creating a file on ext4.
Therefore to avoid a deadlock, all code that takes this lock must use
GFP_NOFS, to prevent memory reclaim from waiting for the filesystem
transaction to complete.
Reported-by: syzbot+0eefc1e06a77d327a056@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
security/smack/smack_access.c | 4 ++--
security/smack/smack_lsm.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -474,7 +474,7 @@ char *smk_parse_smack(const char *string
if (i == 0 || i >= SMK_LONGLABEL)
return ERR_PTR(-EINVAL);
- smack = kzalloc(i + 1, GFP_KERNEL);
+ smack = kzalloc(i + 1, GFP_NOFS);
if (smack == NULL)
return ERR_PTR(-ENOMEM);
@@ -545,7 +545,7 @@ struct smack_known *smk_import_entry(con
if (skp != NULL)
goto freeout;
- skp = kzalloc(sizeof(*skp), GFP_KERNEL);
+ skp = kzalloc(sizeof(*skp), GFP_NOFS);
if (skp == NULL) {
skp = ERR_PTR(-ENOMEM);
goto freeout;
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -268,7 +268,7 @@ static struct smack_known *smk_fetch(con
if (ip->i_op->getxattr == NULL)
return ERR_PTR(-EOPNOTSUPP);
- buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL);
+ buffer = kzalloc(SMK_LONGLABEL, GFP_NOFS);
if (buffer == NULL)
return ERR_PTR(-ENOMEM);
