From: Eric Biggers ebiggers@google.com
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@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers ebiggers@google.com Signed-off-by: Casey Schaufler casey@schaufler-ca.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- security/smack/smack_access.c | 6 +++--- security/smack/smack_lsm.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-)
--- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -469,7 +469,7 @@ 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);
@@ -504,7 +504,7 @@ int smk_netlbl_mls(int level, char *cats if ((m & *cp) == 0) continue; rc = netlbl_catmap_setbit(&sap->attr.mls.cat, - cat, GFP_KERNEL); + cat, GFP_NOFS); if (rc < 0) { netlbl_catmap_free(sap->attr.mls.cat); return rc; @@ -540,7 +540,7 @@ 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 @@ -270,7 +270,7 @@ static struct smack_known *smk_fetch(con if (!(ip->i_opflags & IOP_XATTR)) return ERR_PTR(-EOPNOTSUPP);
- buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL); + buffer = kzalloc(SMK_LONGLABEL, GFP_NOFS); if (buffer == NULL) return ERR_PTR(-ENOMEM);