From f87359b51f61a4baa9bf62faebb6625d518d23b4 Mon Sep 17 00:00:00 2001 From: Alexander Boyko Date: Mon, 1 Jun 2020 08:32:11 -0400 Subject: [PATCH] LU-13617 llite: don't hold inode_lock for security notify 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: 1d44980bcb ("LU-8956 llite: set sec ctx on client's inode at create time") Signed-off-by: Alexander Boyko Cray-bug-id: LUS-8924 Change-Id: I4727da45590734bde57bee9d378b61c30b5d515a Reviewed-on: https://review.whamcloud.com/38792 Tested-by: jenkins Reviewed-by: Sebastien Buisson Tested-by: Maloo Reviewed-by: Andrew Perepechko Reviewed-by: Oleg Drokin --- lustre/llite/dir.c | 6 ++++-- lustre/llite/namei.c | 18 ++++++++++++------ 2 files changed, 16 insertions(+), 8 deletions(-) diff --git a/lustre/llite/dir.c b/lustre/llite/dir.c index a69a1de..a452779 100644 --- a/lustre/llite/dir.c +++ b/lustre/llite/dir.c @@ -517,11 +517,13 @@ 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/lustre/llite/namei.c b/lustre/llite/namei.c index e358e7a..f569da1 100644 --- a/lustre/llite/namei.c +++ b/lustre/llite/namei.c @@ -664,10 +664,12 @@ static int ll_lookup_it_finish(struct ptlrpc_request *request, } if (secctx != NULL && 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", @@ -1205,12 +1207,14 @@ static int ll_create_it(struct inode *dir, struct dentry *dentry, if ((ll_i2sbi(inode)->ll_flags & LL_SBI_FILE_SECCTX) && secctx != NULL) { - 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); } @@ -1376,14 +1380,16 @@ again: GOTO(err_exit, err); 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, err); } -- 1.8.3.1