3.16.79-rc1 review patch. If anyone has any objections, please let me know.
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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
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
[bwh: Backported to 3.16:
- Drop change to smk_netlbl_mls(), where GFP_ATOMIC is used
- Adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -430,7 +430,7 @@ char *smk_parse_smack(const char *string
if (i == 0 || i >= SMK_LONGLABEL)
return NULL;
- smack = kzalloc(i + 1, GFP_KERNEL);
+ smack = kzalloc(i + 1, GFP_NOFS);
if (smack != NULL) {
strncpy(smack, string, i + 1);
smack[i] = '\0';
@@ -502,7 +502,7 @@ 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)
goto freeout;
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -70,7 +70,7 @@ static struct smack_known *smk_fetch(con
if (ip->i_op->getxattr == NULL)
return NULL;
- buffer = kzalloc(SMK_LONGLABEL, GFP_KERNEL);
+ buffer = kzalloc(SMK_LONGLABEL, GFP_NOFS);
if (buffer == NULL)
return NULL;
