File boo1156336-0001-vfs-vfs__delete-fix-double-unlo... of Package lxd

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File boo1156336-0001-vfs-vfs__delete-fix-double-unlock-of-root-mutex.patch of Package lxd (Revision 204c5fc4751257bd542318fe9fd639c0)

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From 13548f8bdb309d18801de9febb8f5829b6b9ae55 Mon Sep 17 00:00:00 2001
From: Aleksa Sarai <cyphar@cyphar.com>
Date: Fri, 31 Jan 2020 20:57:47 +1100
Subject: [PATCH] vfs: vfs__delete: fix double-unlock of &root->mutex

vfs__delete_contents would unlock the passed &root->mutex, but all of
its callers would then also unlock the passed &root->mutex. It turns out
that this works on most architectures without issue, but apparently on
some Intel CPUs with TSX enabled this will trigger a general protection
fault[1,2].

This was the cause of a very frustrating bug where LXD would segfault on
start-up[3].

[1]: https://lwn.net/Articles/534758/
[2]: https://software.intel.com/en-us/forums/intel-isa-extensions/topic/675036
[3]: https://bugzilla.opensuse.org/show_bug.cgi?id=1156336

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
 src/vfs.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/src/vfs.c b/src/vfs.c
index 3a4c205a1d4a..443a6ad3b980 100644
--- a/src/vfs.c
+++ b/src/vfs.c
@@ -619,7 +619,6 @@ static int vfs__delete_content(struct root *root, const char *filename)
 	/* Check that there are no consumers of this file. */
 	if (content->refcount > 0) {
 		root->error = EBUSY;
-		pthread_mutex_unlock(&root->mutex);
 		rc = SQLITE_IOERR_DELETE;
 		goto err;
 	}
@@ -630,8 +629,6 @@ static int vfs__delete_content(struct root *root, const char *filename)
 	/* Reset the file content slot. */
 	*(root->contents + content_index) = NULL;
 
-	pthread_mutex_unlock(&root->mutex);
-
 	return SQLITE_OK;
 
 err:
-- 
2.25.0

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File boo1156336-0001-vfs-vfs__delete-fix-double-unlock-of-root-mutex.patch of Package lxd (Revision 204c5fc4751257bd542318fe9fd639c0)

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