From: Eric Biggers Date: Thu, 22 Aug 2019 05:54:41 +0000 (-0700) Subject: smack: use GFP_NOFS while holding inode_smack::smk_lock X-Git-Tag: v4.19.78~4 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1b42503211ca46711655b834d797f068b1abe59e;p=thirdparty%2Fkernel%2Fstable.git smack: use GFP_NOFS while holding inode_smack::smk_lock 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 Signed-off-by: Casey Schaufler Signed-off-by: Greg Kroah-Hartman --- diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c index 9a4c0ad46518d..c071c356a9637 100644 --- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -469,7 +469,7 @@ char *smk_parse_smack(const char *string, int len) 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 *catset, struct netlbl_lsm_secattr *sap, 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(const char *string, int len) 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; diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 148af904c1872..221de4c755c31 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -270,7 +270,7 @@ static struct smack_known *smk_fetch(const char *name, struct inode *ip, 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);