[lustre-devel] [PATCH 15/18] lustre: llite: don't hold inode_lock for security notify
James Simmons
jsimmons at infradead.org
Wed Jul 1 17:04:55 PDT 2020
From: Alexander Boyko <alexander.boyko at hpe.com>
With selinux enabled client has a dead lock which leads to
client eviction from MDS.
1 thread 2 thread
do file open do stat
inode_lock(parend dir)
got LDLM_PR(parent dir)
enqueue LDLM_CW(parent dir) waits on inode_lock to notify security
waits
timeout on enqueue
and client eviction because client didn't cancel a LDLM_PR lock
security_inode_notifysecctx()->selinux_inode_notifysecctx()->
selinux_inode_setsecurity()
The call of selinux_inode_setsecurity doesn't need to hold
inode_lock.
Fixes: f4d3cf7642 ("lustre: llite: set sec ctx on client's inode at create time")
Cray-bug-id: LUS-8924
WC-bug-id: https://jira.whamcloud.com/browse/LU-13617
Lustre-commit: f87359b51f61a ("LU-13617 llite: don't hold inode_lock for security notify")
Signed-off-by: Alexander Boyko <alexander.boyko at hpe.com>
Reviewed-on: https://review.whamcloud.com/38792
Reviewed-by: Sebastien Buisson <sbuisson at ddn.com>
Reviewed-by: Andrew Perepechko <andrew.perepechko at hpe.com>
Reviewed-by: Oleg Drokin <green at whamcloud.com>
Signed-off-by: James Simmons <jsimmons at infradead.org>
---
fs/lustre/llite/dir.c | 6 ++++--
fs/lustre/llite/namei.c | 18 ++++++++++++------
2 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/fs/lustre/llite/dir.c b/fs/lustre/llite/dir.c
index 463c5d7..e3305f7 100644
--- a/fs/lustre/llite/dir.c
+++ b/fs/lustre/llite/dir.c
@@ -489,11 +489,13 @@ static int ll_dir_setdirstripe(struct dentry *dparent, struct lmv_user_md *lump,
dentry.d_inode = inode;
if (sbi->ll_flags & LL_SBI_FILE_SECCTX) {
- inode_lock(inode);
+ /* no need to protect selinux_inode_setsecurity() by
+ * inode_lock. Taking it would lead to a client deadlock
+ * LU-13617
+ */
err = security_inode_notifysecctx(inode,
op_data->op_file_secctx,
op_data->op_file_secctx_size);
- inode_unlock(inode);
} else {
err = ll_inode_init_security(&dentry, inode, parent);
}
diff --git a/fs/lustre/llite/namei.c b/fs/lustre/llite/namei.c
index 2353a8f..251d6be 100644
--- a/fs/lustre/llite/namei.c
+++ b/fs/lustre/llite/namei.c
@@ -659,10 +659,12 @@ static int ll_lookup_it_finish(struct ptlrpc_request *request,
}
if (secctx && secctxlen != 0) {
- inode_lock(inode);
+ /* no need to protect selinux_inode_setsecurity() by
+ * inode_lock. Taking it would lead to a client deadlock
+ * LU-13617
+ */
rc = security_inode_notifysecctx(inode, secctx,
secctxlen);
- inode_unlock(inode);
if (rc)
CWARN("cannot set security context for " DFID ": rc = %d\n",
PFID(ll_inode2fid(inode)), rc);
@@ -1198,13 +1200,15 @@ static int ll_create_it(struct inode *dir, struct dentry *dentry,
return PTR_ERR(inode);
if ((ll_i2sbi(inode)->ll_flags & LL_SBI_FILE_SECCTX) && secctx) {
- inode_lock(inode);
/* must be done before d_instantiate, because it calls
* security_d_instantiate, which means a getxattr if security
* context is not set yet
*/
+ /* no need to protect selinux_inode_setsecurity() by
+ * inode_lock. Taking it would lead to a client deadlock
+ * LU-13617
+ */
rc = security_inode_notifysecctx(inode, secctx, secctxlen);
- inode_unlock(inode);
if (rc)
return rc;
}
@@ -1370,15 +1374,17 @@ static int ll_new_node(struct inode *dir, struct dentry *dentry,
goto err_exit;
if (sbi->ll_flags & LL_SBI_FILE_SECCTX) {
- inode_lock(inode);
/* must be done before d_instantiate, because it calls
* security_d_instantiate, which means a getxattr if security
* context is not set yet
*/
+ /* no need to protect selinux_inode_setsecurity() by
+ * inode_lock. Taking it would lead to a client deadlock
+ * LU-13617
+ */
err = security_inode_notifysecctx(inode,
op_data->op_file_secctx,
op_data->op_file_secctx_size);
- inode_unlock(inode);
if (err)
goto err_exit;
}
--
1.8.3.1
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