linux-kernel - [tip:locking/urgent] locking, fs/locks: Add missing file

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Date:   Tue, 18 Oct 2016 02:31:03 -0700
From:   tip-bot for Peter Zijlstra <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, dvyukov@...gle.com, peterz@...radead.org,
        torvalds@...ux-foundation.org, jlayton@...chiereds.net,
        bfields@...ldses.org, linux-kernel@...r.kernel.org,
        mingo@...nel.org, hpa@...or.com, syzkaller@...glegroups.com,
        viro@...iv.linux.org.uk
Subject: [tip:locking/urgent] locking, fs/locks: Add missing file_sem locks

Commit-ID:  1c7df9c183278052aedc3dcb9fecb8bf2b24a659
Gitweb:     http://git.kernel.org/tip/1c7df9c183278052aedc3dcb9fecb8bf2b24a659
Author:     Peter Zijlstra <peterz@...radead.org>
AuthorDate: Sat, 8 Oct 2016 10:12:28 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 18 Oct 2016 11:19:05 +0200

locking, fs/locks: Add missing file_sem locks

I overlooked a few code-paths that can lead to
locks_delete_global_locks().

Reported-by: Dmitry Vyukov <dvyukov@...gle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Jeff Layton <jlayton@...chiereds.net>
Cc: Al Viro <viro@...iv.linux.org.uk>
Cc: Bruce Fields <bfields@...ldses.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: linux-fsdevel@...r.kernel.org
Cc: syzkaller <syzkaller@...glegroups.com>
Link: http://lkml.kernel.org/r/20161008081228.GF3142@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 fs/locks.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/locks.c b/fs/locks.c
index ce93b41..22c5b4a 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1609,6 +1609,7 @@ int fcntl_getlease(struct file *filp)
 
 	ctx = smp_load_acquire(&inode->i_flctx);
 	if (ctx && !list_empty_careful(&ctx->flc_lease)) {
+		percpu_down_read_preempt_disable(&file_rwsem);
 		spin_lock(&ctx->flc_lock);
 		time_out_leases(inode, &dispose);
 		list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
@@ -1618,6 +1619,8 @@ int fcntl_getlease(struct file *filp)
 			break;
 		}
 		spin_unlock(&ctx->flc_lock);
+		percpu_up_read_preempt_enable(&file_rwsem);
+
 		locks_dispose_list(&dispose);
 	}
 	return type;
@@ -2529,11 +2532,14 @@ locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
 	if (list_empty(&ctx->flc_lease))
 		return;
 
+	percpu_down_read_preempt_disable(&file_rwsem);
 	spin_lock(&ctx->flc_lock);
 	list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
 		if (filp == fl->fl_file)
 			lease_modify(fl, F_UNLCK, &dispose);
 	spin_unlock(&ctx->flc_lock);
+	percpu_up_read_preempt_enable(&file_rwsem);
+
 	locks_dispose_list(&dispose);
 }